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Hi everyone!
My wagon developed an intermittent misfire at idle, nothing major, just a little jolt here and there. Those misfires worsened quickly, and now it's running very rough at idle, and when revved up, under load or no load.
I checked the codes, and they're all 1-1-1. The plugs, cap, rotor, wires were replaced around 20k miles ago. Any ideas? Thanks!
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The current condition is no change! Still the same rough running engine.
I have no error codes. I've installed a new CPS, new fuel filter, new O2 sensor and cleaned original Bosch injectors (though probably not enough, they all spray solid and fairly equal streams now). I've swapped out my AMM (MAF) for my known good backup and there was no change. I've swapped out my ECU for my known good backup and no change. My plug wires are NGK and have 20k on them, they all test 310 ohms each. The cap, rotor, and plugs were also replaced then. I replaced the timing belt with a Continental belt 2k miles ago, and readjusted the tension approximately 200 miles afterward. I replaced the intake gasket with a thick OEM 2k miles ago. The ECT moves through the heat range per Art's very nice chart. Compression tests 150+psi across all. I've gone through the hoses and most are new or past couple years, low miles. There's actually pretty good vacuum considering how rough it's running.
I found a set of new injectors that will be arriving tomorrow. If that doesn't fix it, I'm totally stumped and ready to convert to EV. A little joke, but also serious once it's practical to do so.
Any ideas to what I'm missing? Thanks so much to everyone who've shared their thoughts and great experience!
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Hi,
You say you have changed just about everything that is supposed to be plug and play.
From the video I have to say the engine is running very rough but at the same time very evenly.
Once past initial start up and late in the warming up time you are saying it gets rougher until it looks like the video on Turbo Bricks. That is a definite roughness but very consistent in my experience.
It appears to be very lean all across the spectrum of ignition and combustion firing.
What ever is wrong effects the whole in and out process of combustion.
Let say that the fuel delivery system is working just fine, but the air mixture turns worse after the ECU moves off its startup program. The one where it ignores the O 2 sensor because it’s not hot enough yet to do any good.
The ECU goes with a preset richer mixture and timing sequence until it gathers up a reading from that O 2 sensor.
It should be working with the ECT and the AMM on the intake side.
IF you have a air leak from or on the AMM’s backside. If so, that input is almost useless.
The mixture needs to lean out past start up quickly and the spark timing will always be jumping around a little bit if the rpm isn’t stable. The ECU is self tuning, of a sort, but in the blind.
You have not, that I have seen addressed the throttle plate adjustment and if the accordion tube from the AMM is completely sealed up.
The intake manifold is easy to put a gasket under but you could have a wire under one edge of one of the intake runners. I have almost done that myself. There are one or two loose wires slipping around when things are undone during a major repair.
Art suggested checking the nuts but “it just might” be more involved than that by an accident.
If the gasket hasn’t been run all that long you might get away with pulling it back for an inspection and see if it has been compressed evenly.
Another thing you have not said anything about is the original spark coil relay behind the battery.
If its wiring is not in the greatest shape the signals from the ICU can get delayed or if the component itself is aged it can not be firing the plugs in a changing time frequency of dwell to the coil.
Resulting in variations of spark durations and likewise false combustions
I know it sounds like a long, long shot but I personally would like to rule it out.
In my other post I did that as the last thing before going off and blaming the ICU and the ECU that you have already done.
As far as the spark plug wires 310 ohms is a very low reading. Maybe you have solid core wires I don’t know but a 8 to 11,000 ohms is stock for radio frequency suppression.
Even the spark plugs can come with resistance values for the reasons of the high voltages.
In my experience running sparks plugs other than the stock silver streak set and a .028 gap is asking for odd performances when nothing else can make sense.
What are you using?
I’m not ruling out any of basics of the the three sided triangle of combustion.
I will say you are rattling around on some very slim choices of what else can be going on with this engine.
I truly believe there is a basic “honest to gosh” simple reason.
I’d stress start with the ignition and then the air.
There’s a point where the two sides of the triangle touch.
No matter which way you way you spin the rod to make it ring, Meal time! 🤩
The electronics is just twisting the puzzle as best it can! It was designed that way.
Ignition is the oldest (135 years) of a simple technology. Wires were of flat copper or brass strips of metal.
Solid core Silicon Racing wires the latest buzz …really?
The ignition systems are depended on the heaviest and now with unbelievable RPMs past mechanical points.
We still use “jump a gap” rotor buttons. Copper terminals caps were a better choice so I hope you have them as well.
I cannot say that placing ignition smaller coils down inside, on top of a engines head, is in the long term more reliable. Heat degradation will be on the consumers pocket.
It does do away with travel distances, by a few nano seconds but the 18 gauge harness to each was a bean counters cash draw too.
Hopefully can the coils last as well? Scott Kilmer swaps them around and lets the scanner tell him again if it moved. He is yours and our kinda man!
Rethink and redo something, as this is the first side of getting things to burn correctly.
Even if it’s propane or ethanol, you got to get it in there.
The best made radio & microphones can sometimes be worthless like a thin string or tin can for a speaker.
Phil
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Phil, you're my favorite modern era philosopher! Bravo and well said my friend!
It may be very lean, but the #3 and #4 ppl plugs are very dark #1 and #2 are better, but not perfect.
I've sprayed starting fluid all around the intake gasket from every angle, saturated everything there, and the AMM feed hoses to the throttle body, and other hoses. I feel 100% that there are no vacuum leaks.
I'll check the spark coil relay.
The 310 ohms is the readings I get on the NGK wires I bought from IPD. I've checked my meter with a 1% reference resistor, so I assume my readings are good. Today I swapped them with a new set of Bremi Germany wires that read 6k ohms each and 1k ohms on the coil to cap. Same results, rough running.
My local Indy Volvo guru shop thinks it must be the ECU. He's going to let me test one in the car to see.
Other than the spark relay, I feel I've covered everything I can think of. Please keep the ideas coming! Thanks so much!
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Hi,
Glad to hear that you haven’t looked into that gadget behind the battery yet.
It’s an inconspicuous item, flopped right in the middle of the ignition system.
It looks so simple and small but isn’t everything in the other two electronic items that you have tested.
As far as exchanging the ECUs again, I don’t know what you will gain unless you have never done a hard reset to the one in the car now.
A hard reset is leaving the whole EZK system disconnected from the battery for a real long time.
His ECU has been disconnected so who knows?
In my recent circle chase, it was like almost a week before I was got back to putting the battery back on.
The last things I messed with was exchanging the spark coil relay component and hooking the battery back up. The 30 second running and dying thing totally stopped.
Doing one thing and then testing for a result of change is the only way I think.
I’m stumped as well on last component that you are about to TEST … check out?
I believe you are definitely slowing down, due to a shortage of things to test, so restraint is on its way.😎
I have only read the following in industrial magazines about shielding from electrical noise from the air and other ways signals travel through power supplies lines.
The electric smart meters on your home use the very power lines as a communication circuit.
So many ways a person can be wired and it’s the future of speed within technologies.
A hard reset is supposedly done quicker by putting the two the battery cable leads together so everything in all the circuits everywhere, discharge to zero or a virgin status.
Like in no static charge held on surfaces or inside these highly sophisticated chips used today.
I suggest clamping them for several minutes to give things a rest and deplete out.
Nothing to lose except time and you can do other things in the meantime.
A good cleaning and inspection can always be justified on batteries.
A Couple other things that have popped in my mind.
One is to ask if this car has an EGR valve?
If it opens at the wrong time or hangs open the engine will run rough.
Hot Exhaust gases lean out or dilute the mixture.
I have had to clean the controlling valve to it twice on my 1991.
The valve is Located on the left fender. It can get a clogged port below the tiny cap. It doesn’t vent properly.
It trips the CEL, if the ECU doesn’t see a temperature change from the sensor inside the EGR valve itself.
Apply vacuum to the valve directly to see if the steel stem moves back and forth with its diaphragm.
Second thought is the valve on top of the fuel vapor canister.
The canister is mounted below the left side front bumper.
The valve is only supposed to open during idle or during high vacuum times.
It function is to pull air and gas vapors from the fuel tank.
If the smaller hose going to it from the manifold or the larger hose from the valve to both ports above the throttle plate body.
If the valve gets plugged up and doesn’t close off then it’s sucking air from the fuel tank all the time.
A rotted or split hose IS an air leak. I have found such a bad hose rotten just out of sight under the frame to the canister.
These ports have “sized” nipples so don’t get them or the hoses reversed, if that’s possible?
The throttle plate is centered underneath these port holes.
Another reason for a proper adjusted, cleaned and sealed throttle body to the manifold.
There are four cylinders as it’s not the one intermittent misfire that you started out with.
A bad spark plug or the wrong gaps cause this most of the time and then it gets worse.
There has to be an explanation for this rather repetitive roughness.
Phil
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Phil,
My car has no EGR.
I'll check the valve on top of the fuel vapor canister and hose.
Thanks!
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Hi
I forgot to mention in checking the vapor canister you can confirm if there is a problem on one the one side going down there.
If the large vapor line doesn’t hold a slight vacuum with the engine off then is has a problem with letting air into the intake manifold.
This not not prove there isn’t a problem with the valve on top of the canister though.
The other smaller line causes the valve to open so if you apply vacuum to it then the large vapor hose it will vent the canister. You will want to check its ability of operation to be able to open and close regularly.
FYI there’s supposed to be carbon in the canister emissions system to absorb condensing vapors until drawn off during idles. So it can absorb some small amounts of vapor from the tank.
I guess it’s explains mounting it under bumpers shade or tucked out of site period.
Gas caps vent off any overpressure but before that, the canister is supposed get a lengthy shot.
Sometimes you might hear the gas tank sound off, in a quiet car that’s sitting in the sun or if the gas has been agitated to some excessive extent.
The return line is doing that while pumping.
Actually that holding pressure can be quite a bit higher than my mouth can apply but I can suck air through the cap from the protruding screw side fair easily.
You can inhale but you cannot exhale. 🤪 Sorry Bill C.
A drop in altitude will add air to a tank to let air in to get gasoline out but if you climb another steep grade it equalizes.
I can only imagine how an aircraft deals with those conditions.
I noticed on big planes they fill from under the wing too! 🤔 Nice piping?
Gas caps are simple devices, work quietly but are very important. More so on with new car emissions standards. That why they get monitored.
I have heard of a few cars getting traded in for a CEL, that was later found out to be only a gas cap. 🫣
I looked into Art’s pictures and I agree wrenching on the Volvo filter is best done with an impact driver.
It may not look like it takes that much to loosen or compress those copper washers but surprise, it does!
With it hanging down from under the car its a grappling challenge.
Phil
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Just an update to "Current Condition and Part Changes" from the TB forum: Jim got it running sometime yesterday after replacing the cap and rotor.
https://turbobricks.com/index.php?threads/1992-245-intermittent-misfire-now-permanent-rough-running-no-fault-codes.370190/post-6345533
--
Art Benstein near Baltimore
"Whoever said the pen is mightier than the sword obviously never encountered automatic weapons." - General MacArthur
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Thank you for keeping us or me in the loop Art!
I would have never gone over to there as I’m not a member to reply to turbos as I have never owned or driven one.
In a post, before I got off into the excessive air possibility, that I recently completed was that the whole engine was firing poorly.
It was along that line that I said, something right in the middle of the ignition system was what I considered the problem.
I took it that his 20,000 mile idea is as new as he could get it.
Shame we all couldn’t see it shake until now.
He told me he was going to check out the spark coil relay behind the battery.
So I relaxed.
We both have had suspicions shout that gadget and or its connections.
Maybe he did or didn’t check it as he done a lot of jumping around for his $680 puzzle.
I feel the car was well past due maintenance. It is all original as kept saying.
Another 400 thousand more miles is a terrible dream with the automotive or transportation industry being in such a turmoil.
Maybe he thought about as what’s in the middle a few more times and went back with the basics again?
IMO That’s that we all should do?
The Cap and Rotor explains a lot!
I don’t agree with the statement on turbo bricks that they can only last 10,000 miles but facsimiles are out there.
That system of components was used for many decades across several makes of vehicles and we know what drives a market. $$$ and sometimes a few cents is craziness, but logical, if considering the production numbers that has paid for the tooling and R&D many times over.
I have taken used Bosch caps, rotors and some ignition wires from scrapyards and stashed them.
I really do not about what is being sold in these inflationary days as quality or how a lot of manufacturing skill shortages are affecting their presentations.
There has been a many junkers found in the past with those components replaced as an attempt to avoid the graveyard as the cost of repairs have skyrocketed.
Maybe that 10K theory was a little too vibrant depending on availability from then to now?
So I’ll reserve a space that the Turbo’s post could have some validity.
Phil
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Hi Phil and Art,
I meant to post here earlier but had to start my overdue 750 mile trip in the car. Everything is going well so far as I e arrived with confidence in this beauty I've had for 21+ years.
I also thought the 10k miles was short for a quality Bosch cap and rotor, but things change.
Phil, I never checked the vapor canister, but realized the vacuum hose going to it had been disconnected and capped at the manifold at some point. I don't remember doing that so it must be before I got the car. Which is strange because I bought the car from the original owner who owned the Volvo dealership. It was his wife's personal car and all maintenance was done at the dealership. Oh well. I'll install a vacuum line when I return. That explains the occasional fuel smell.
I really appreciate everyone's help!
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Hi,
Please describe further your observation:
"....the #3 and #4 ppl plugs are very dark #1 and #2 are better, but not perfect"
Very dark as almost black? Carbon deposits on plug could conduct electricity and drain away spark energy. Could be the answer why engine runs better when you pull #3 cable off ie. more energy reserved for next spark
Try cleaning the plugs a bit. Use wire brush and carb spray. Or put in a new set maybe?
Amarin
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Amarin,
There's no carbon buildup, the dark is from what looks like a rich condition.
I understand what you're saying about more energy for the next spark, but why does pulling #1 or #2 instantly kill the engine? And #1 and #2 plugs look ok. Thanks!
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Hi Build,
"I understand what you're saying about more energy for the next spark, but why does pulling #1 or #2 instantly kill the engine? And #1 and #2 plugs look ok"
Yes this is weird. In normal situation when you pull #1 or #2 out the engine should still be running. Subsequent sparks from #2 #3 and #4 should sustain running the engine.
My thought is (when you pull out #1 for example) the remaining spark energy channeled to #2 #3 and #4 not enough (in your case) to sustain engine running. So naturally I'd lay blame on the plugs, plug cables, rotor, distributor and lastly ignition coil causing weak sparks.
There are known cases of faulty ignition coil when hot. It causes misfire at certain RPM but in your case, misfire happens at all RPMs. Less likely to be ignition coil.
Amarin
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Amarin,
I've swapped the plugs around, no change, installed new plug wires, no change. The cap and rotor look perfect at only 20k miles.
My coil tests on primary side 11.2 ohms to ground and 2.54k ohms to ground. On secondary 7.98k ohms to ground. No corrosion anywhere on any connectors I've had off during this work. This car has never seen snow it's whole life, except for in Dec 1991 when it was completed in Sweden. I'm fortunate that it's rust and corrosion free, except for right now when it's not running. I'm out of ideas.
I'm checking Phil's suggestion about the spark relay.
Thanks
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I just replaced the 20k+ mile NGK plug wires with new Bremi Germany wires, and there's no change at all.
I just replaced the injectors with new made in USA Standard, and have swapped their wires around since they all fire at the same time. Tested it, then swapped #1 with #4 and #2 with #3 wires, no change whatsoever.
Fuel pressure 45-70psi depending on rpm.
There's equal fuel from each injector, there's equal compression, there's spark, which I assume is equal, new quality wires, cap and rotor looks new at 20k miles. Whats missing here?
Thanks!
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You may have already tried these things - not sure.
On my 93, the OBD has a test function that fires each injector separately. Yours may have it as well. I've used this on a few occasions to ensure that each injector has connectivity and 'sounds like it's working'. I don't have the instructions, but post back if you need them. I believe they are in the Bentley manual.
For a while I chased what looked and sounded like a rough engine - idle, through acceleration. I tried many of the things you did, nothing worked. I finally pulled the intake manifold and discovered the gasket had worn away on the front cylinder and was letting in unregulated air. I could not see it with the intake mounted. Replacing the intake manifold gasket and carefully buttoning everything up solved the issue and the engine purrs nicely now.
Thanks,
Jeff
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I was able to swap the #1 and #4 injector wires. There's no change to the rough running when I pull the new #4 wire, and the new wire to #1 kills the engine instantly when I pull it. There's obviously no fuel coming from #3 or #4 injectors.
When running the OBD pin 2, press 3 times, I can feel each injector engage strongly, and the IAC activate strongly. I assume #3 and #4 injectors are clogged? Granted they are original to the car, Decemeber 1991, and my car has 460k miles on it.
Ideas? Thanks!
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Hi,
Ok now … we are sliding sideways in a guessing game.
You had better get more methodical or you will be circling for a long time.
I can only tell you that when you get off into the wiring game of the injectors that they are wired in pairs if you locate a schematic.
The sets of injectors will be powered by an orange wire via a route with the AMM.
If you do not have power at the AMM orange wire the injector system will be dead.
That’s not the problem unless you lost power via a system relay.
The injectors can be pair together from the orange wire. Your wiggling may have lifted up another lid to a pandora box? I’ll leave that to my opening statement.
The ECU grounds the injectors by running the power to ground through transistors in side it from my understanding.
I don’t if the ground connection goes all the way back up to the engine but many have claimed to make sure you have good grounds every place you have one.
A single wire is the grounding side of any circuits and that in itself constitutes one half of everything.
Disrespect your ground and that’s what you will get … grounded! Nothing goes right at all. This has been my experience.
I sincerely doubt the engine would even run or start very well under any of that above.
The orange wire is powered by the two part system relay under the glove box. FYI, The pumps run on the second part of that relay.
This is a whole other troubleshooting technique and you should be past that.
I will say this I truly like WoodShavings thoughts on the intake manifold gasket as with gone awry.
If this car is as original as you say it is you had better consider his point of excess air!
It explains a simpler version that you started out with.
Engines can run lean and imitate many other symptoms of improper combustion.
For about $10 it’s an easy fix or an elimination.
Keep going with the posts to help shorten your learning curve.
Like the car, it’s how we all started out as an original item! How well we improve depends on intervention.
Final note:
If the CPS looks that bad from the outside, as you have said, you have an open can of worms all by itself.
Phil
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Hi Phil,
I've made some progress, but I'm still where I started.
I replaced the CPS and no change except for a little peace of mind. Lots of frayed bare copper on the old one.
The O2 sensor reads a constant +.589vdc all the time, regardless of rpm or engine temperature. Causing this problem?
I've activated the OBD pin 2 test for the injection activation. I clearly feel and hear all 4 of them activating, and I feel and hear the IAC valve activating.
I have 150+psi on all 4 cylinders.
If I disconnect the MAF, there's no change. I tried my backup MAF and there's also no change (though it was a little tougher with the backup since it has never been cleaned properly).
Still, if I pull #3 plug wire it runs smoother. So weird!
Ideas?
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Hi,
I see you said you’re making progress and that is getting rid of that scary CPS. That’s a boy!
An oxygen sensor should be outputting a consistent voltage that varies with a few tenths of a volt but centered around the .5 or 500 millivolt range.
One volt is divided into 1000 pieces and is a very low voltage indeed.
A digital voltage meter has to read out its display and have a fast refresh rate.
The numerals change rather quickly.
With that said it’s hard to say if it’s working correctly.
Are you using the lowest scale available on the meter?
You cannot use any auto ranging as it works too slowly.
I have a visual meter just for oxygen sensors made by ACTRON.
I inherited, from a passed neighbor so it’s aged since 2005.
It uses ten red LEDs in a string to read voltages changes instantaneously.
It also has a set of rich or lean colors it flips between.
It also has a fixed pulsing frequency signal output but I don’t know how or where to use it on a 240.
The package covers newer cars mostly with lots of codes.
Maybe it checks injectors but it says ignition modules and sensors on it.
I have concluded with it, that if an oxygen sensor isn’t flickering some changes, it probably dead or can show laziness. I personally understand laziness. 😴🥴
The oxygen sensor adjusts the ECU on the backside that’s opposite the AMM on the intake. It is mostly the Self-Tuning aspect of this system that has really expanded its usefulness to keep newer cars on the highways today. I have heard that Ford has put as many as Seven, on one model of their cars. Ouch, on that maintenance service order! That’s truly a “Fix Or Repair Daily” vehicle as it ages.
No need to be messing around with the AMM.
Don’t do anything with it while it’s running. Thats a Bad habit to be cultivating.
Refrain from yanking on today’s sophisticated computers with adaptive learning unless you like codes.
INTERESTING why you pick on number three cylinders wire?
Maybe it’s so lean from a intake manifold leak it actually helps? Now I’m guessing 😬
Is your exhaust manifold and connecting pipes not leaking.
Just guessing about the oxygen sensor. 🫠
I had better sign off as I will add to your confusion.
I’ll keep an eye out for progress.
Phil
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Hi Phil,
My meter was set for fast fluctuations, but I didn't see any. I've realized that the O2 sensor had been coated in oil from my former front cam seal leak for some time, so it's probably dead. But I'm not sure it would make this run so rough either way.
I've replaced the exhaust manifold gasket within the last year, and there are no leaks elsewhere.
How I found that the engine ran better without #3 plug wire connected was trial and error. I was checking each one to see if they effected the roughness. It's so weird that having #3 unplugged would make it run better. That's originally why I thought I had a timing issue.
On to more tests. I need to get this fixed soon, I have a long trip coming up this weekend.
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Hi,
Just got your reply.
If it were me I would dive into changing the intake manifold gasket as it’s the easiest next thing.
Remove the nuts and ease it back enough to lay it a couple inches above the studs and clean both surfaces up.
Most people are surprised at how frail the gasket is under there.
Oil and gas fumes soak it all the time.
Air leakages needs to be eliminated and down under the manifold can make testing a futile attempt.
The intake material expands and contracts and the replacement gaskets are IMO, too thin.
OEM seemed to be by Victor-Reinz, Wahler German thermostats and Mackay hoses from Australia
Trouble is their distribution here is very limited thanks to the parts chain of warehouses that are always consolidating to what moves with the best for a ROI.
The best you can do is get rid of any old gasket just like the CPS.
If it’s been changed it’s got a thinner one in there or that OEM one is finally shot.
STEP by STEP and in this case, it’s those two major ones to eliminate.
Hopefully it will be like a new pair of shoes!
We’re you planning on taking this car or just wanting to finish up the tidbits before leaving?
I think you have tested everything well enough to move on to basic wrenching.
Just a humble Opinion.
Phil
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Hi Phil,
I changed the intake gasket with thick oem about 2k miles ago.
I have a feeling that it's clogged injectors as they're original to the car, and 460k miles. I haven't cleaned them in the 21 years I've owned the car, and there was no service records of them being cleaned before me. When I bought the car it had just over 100k miles on it, and had always been serviced at the dealership. I bought it from the owner of the dealership, it was his personal car.
Yes, I planned on taking this car on my trip as it's my daily driver and has been everywhere. She's just having a little unfortunate problem right now.
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If you feel the injectors could be clogged, have you tried swapping a pair to see if your symptoms change?
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Intake manifold gasket: I liked that too! Only 2K on it? Check those nuts. Also have another look at the wiring to the ECT sensor, if that got touched during your gasket job.
By the way, if you were looking for an "orange wire" somewhere in your process, the folks at Volvo changed its color to red/black in '92.
I posted a safer way to check your injector spray pattern to your thread on TB.
--
Art Benstein near Baltimore
"Never trust the work of the last guy, even if you're the last guy"
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Hi Art,
I didn’t know about the color changing in 1992.
It’s amazing how much information you have and that you keep it so organized.
There seems to be a couple threads on here that are running parallel in symptoms between missing combustions or running rough along with some head rework being done of which the intake manifold gasket should have been changed.
This covers three cars with this dilemma. A 1987, 1991 and the 1992.
It can get confusing for me about which car I’m trying to respond to.
My 1993 just ran me around the elimination circus.
At first it just quit and then would restart and go quite a bit.
Then later It later progressed to having be towed home a few miles.
That lead me to a tank feed pump replacement even though the gas tank was nearly full.
Then right after that job it did it again at home.
It ran only run for 30 seconds while still on the lift.
A good thing but so predictable for a component to fail so regularly?
It got me to thinking that maybe the CPS but it didn’t look bad so I put in a new one from API electronics that had been sighted as a good price. I bought three and hadn’t changed this one out.
The scenario continued on even after that.
Then I remembered, on this car right after I got it, I found the spark coil relay had a broken connector on the harness. I was servicing it for the heat sink paste.
I didn’t have a spare harness then, so after cutting some grooves in the back of heat sink it was up tight with wire ties. That was like four years ago.
I had convinced myself that it could cut things off so I’ll put in a different relay too.
Only the timing it took for each restart was still sitting in the back of the brain.
I don’t like blaming ICUs and ECUs but …?
It’s usually something external to them as we know.
After digging out a salvaged nineties harness, with all its components, I permanently borrowed the end plastic connector.
Of course, After removing the battery to put it on, I was not thinking that this was probably a hard reset for the ECU.
This I have read about some issues between Brickster’s B.B. and our forensic friend in Malaysia.
Except he is into dissecting ECUs in his spare time. Looking for weak solder joints and capacitors.
I don’t see what else he can play with but it’s interesting but very high weeds for me!🫣
The battery was disconnected for a long time because I had messed up two pins trying to get them to release.
Those pins are made in two pieces as one of them is the locking mechanism.
I borrowed those to transfer over onto the original pins. So it’s all back to factory status and no wire ties.🤫 to be discovered after I’m gone.
I had to modify a tool that was made to release them by milling extra clearance for more depth to push the tangs. They were about .060 to .100 thousandths too short.
The relay’s connector is unique as in deeper, like the AMM, over the injectors, I think?
So I fired up the car. All was gone and I have put about 500 miles on the car since with many restarts.
No timing out in 30 seconds, of which makes me think, it takes about that long for the ECU to drop out of a fixed warming up program.
It then runs on outside information from sensors that we are recognizing as failure components.
I’m not sure between the three interventions, what else fixed it? But I’ll take it!
I’m not so readily willing to go back and put old things in to find out. Especially a feed pump!
The 1993 is different, as we know..
My thoughts are the 1993 car was a on-going run into the 900 series and so forth.
What do you think about what could scramble up a “limp home situation” within the ECU?
An Adaptive program might be working overtime. For me, it could be an explanation.
I might need to ask this to the 900 tab or on Turbo Bricks, if I dare to show my ignorance to that crowd.
I didn’t know that this fellow was also on Turbo Bricks getting advice.
Sort of explains all his testing and modifying wire locations.
Nice to see you are still on here helping with our educations.
Phil
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https://turbobricks.com/index.php?threads/1992-245-intermittent-misfire-now-permanent-rough-running-no-fault-codes.370190/
--
Art Benstein near Baltimore
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Thanks Art,
I hadn’t been out there to that site but you confirmed my suspicions, didn’t you?
I can honestly say again, too many cooks in a kitchen changes the courses of the meal.
TOO many suggestive mechanics under a hood can delay a fix.
If my 1993 hadn’t wound up fixed the way it did, I alone would still be out there going through the basics.
Phil
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Hi Phil and Art,
I agree with you both, and originally posted to both sites because I was lost on this one. And I'm still somewhat lost on my beloved wagon.
Currently I'm stuck on replacing the long overdue, original to the car, fuel filter. Any ideas on these stuck banjo bolts? I've already crimped up the original fuel line a bit, and wonder about that as well. Thanks, Jim
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Jim, I'm approaching this from the perspective of my experience with LH2.4 240s of similar age and mileage as yours being used as daily drivers, not sitting cars or second cars. It is the only experience I have. That makes me very skeptical that yours, similarly described, suffers from fuel contamination or clogged injector screens, or even a clogged main fuel filter.
I would approach this, not by swapping parts in a guessing game, but by making careful measurements as you did when you checked for head gasket failure with a compression gauge. The injector spray pattern failing miserably, as you reported on TB, is puzzling, if your fuel volume and pressure is stable and correct.
Measuring delivery volume and pressure is indeed easier than replacing the fuel filter. Putting on a new fuel filter is easier if you have an impact wrench. I would never attempt one without it. In fact, I believe that huge filter might give you half a million miles without clogging, if your car is indeed driven "daily" and not allowed to run low on fuel.
(From 240 Volvo Fuel Line Fun )
We're here to help, most of us, on multiple forums. Nothing wrong with posting to different groups, it is a good strategy. But recognizing the good advice is an acquired skill. You'll find well-intended thoughts from all levels of experience and many who think all Volvos are alike.
--
Art Benstein near Baltimore
“understanding a question is half an answer” -Socrates
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Hey Art,
Yes, thank you so much, as always. And I welcome all advice and thoughts, but sometimes things get out of hand quickly, like the radio suppression relay from the other forum. Everyone has their own experience.
It's a true daily driver for the past 21 years I've had it, and many long 1000 mile trips, and I wouldn't hesitate to go on another today if it were running correctly. Actually my trip is delayed because of this.
I've replaced the fuel filter and no change. I still haven't found my fuel pressure gauge and wonder if I've leant it to someone. I'll get one and check the pressure though.
I'm still very curious as to why this problem happened instantly. And I don't understand why pulling #1 plug wire kills the engine, and pulling the #3 plug wire makes it run smoother. Ideas? Thanks so much!
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Hi Build,
I saw in your youtube video (which link I got in TB from Art's parallel post) you're using blue NGK plug cables
If my "forensic eyes" aren't playing tricks on me I think I saw few burnt spots along them (blackish area along the cables)
I'm using macbook so I could magnify your youtube video and they do look like burnt spots. I don't think they're oil stains
Check their continuity with ohmmeter
I think weird occurrence like engine dies when pulling #1 plug wire points to haywire ignition ie. faulty cables
Another daily driver in 900 series,
Amarin
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Hi Amarin,
I see what you mean, it does look burned, but they aren't, only grease stains from an earlier oil leak. They're pretty new, but I'll check their resistance. Thanks!
The resistance of each was 310 ohms. 20k miles on them. Good?
Im currently not showing any error codes though it's still running very poorly like it has been.
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Hi,
Is it 310 ohms or 310 kohms?
NGK's info on their blue plug cable is about 8 kohms per meter. Check again?
Another test. With engine running use a spare plug and see what is the colour of the spark. Yellow means weak spark. Blue means strong.
Hope this helps,
Amarin
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Amarin,
I've checked all of them again and each is 310 ohms, the coil to cap wire is 308 ohms. I've bought a new set of Bremi Germany wires and have installed them. They're 6k ohms per wire, 1k ohms for coil to cap, no change, still poor running.
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Hi Phil,
Wow! You've seen it all! Between you and Art, I know there's no stone left to be uncovered!
I've cleaned the injectors, maybe not what they should be, but they're spraying now. I've replaced the O2 sensor, because it was time for it. I've tested the coolant temperature sensor and it checks perfect resistance to specs.
The interesting thing is, this morning when it was cool, the engine started and was 100% it's normal smooth self. It had normal power, smooth running, perfect! As the engine warmed, once it hit a certain temperature, instantly the rough running came back full force. This happened instantly! The daytime temperature is too high now to test this again, but it was perfect when it was cold.
What does this mean? For some reason I think it's a strange acting AMM (MAF)?
Thanks my friend!
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There was no change when moving the wires around, even though it all is falling apart.
When I pulled the injector wires one by one, losing the #1 and #2 injectors caused the engine to die instantly. Losing the #3 and #4 injector had no effect at all.
What could be causing this? The injectors themselves? Losing two at the exact same time seems strange? Ideas?
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I just noticed that the CPS wire is falling apart in one area, extremely loose and frayed, I can see all the way through it. It's the original from 1992. I assume this is the problem?
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Hi,
I’m glad to say you are on it today!
That CPS NEEDS TO GO!
The ECU can only deal with so much misinformation of signal inputs.
The CPS starts up everything.
Like I said the ECU does several things to keep the engine performing but monitoring itself wasn’t a strong point as of yet in our years.
The ECUs have evolved a long ways from the early eighties even on your car.
Of course, thus didn’t stop on in to the 900 series either.
These two series of cars were stepping stones to increasing control to a point that if maybe turn to be ridiculous. Having to a a code for a battery change out bothers me.
The TPS is in the middle, or on the side lines, of the two crucial parts of controlling how the engine does anything. It shifts programs under normal circumstances.
Cleaning the throttle body and putting the TPS in sync will help get the engine off the problem of it dying.
It appears the IAC might be out of the loop with the ECU but erratic signals from the head man, the CPS,
this is what can make things more weird.
If the rest of the BRICKBOARD is like me, they are very happy for you nailing this thing down.
Phil
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Phil,
You're on the heart of the problem once again my friend!
I haven't swapped the CPS yet but have found that the #3 and #4 injectors aren't working properly. If I pull their wires there's no change to the engine. If I pull #1 or #2, the engine dies instantly.
Even after I swapped the #2 and #3 injector wires, it's the same. When I pull the new wire going to #2 it dies, the new #3 has no effect when I pull it. I can't swap any of them to test #4, the other wires aren't long enough to reach. Ideas?
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Hi,
You did the right thing to do the electrical tune up of the ignition system.
It’s a weak link by nature let alone age.
I assume it was rough before or you were doing routine maintenance then but did your wire set come with a replacement coil wire? Some do not.
I will hope it’s not the quality of the components becoming the issue again.
The code lights do not do much towards diagnostics in general.
They are very generic and give open ended interpretations to any mechanic.
A rich lean mixture is its favorite code and might as well be a bucket full of possibilities.
These codes were not sophisticated, by any means and long before adaptive technology, that covers up issues good enough to fool politicians.
These management systems were stepping stones but mainly addressed those emission regulations.
The CEL is an emissions system alert apparatus for maintenance thoughts. Gotta take to a shop again?
The check engine light was the star just peeking over the horizon and leading to future systems to keep combustion engines doing their thing.
The 1989-93 were built on the “proximity sensor circuit technology” that’s now used a lot today.
The Crankshaft Position Sensor was first for these cars and have a history of being prone to different symptoms of early failures.
Some of carry a spare but it’s can be a bear to change out even at home.
Do you know how fresh yours is?
Check the cabling going over behind the head and between the firewall for deterioration.
These computers are very fast in correcting a miss fire but have their limitations.
The corrections are made that can make a simple thing into a mystery for electrical/mechanical detectives.
Since the CPS in is the beginning of a chain reaction of firing the spark plugs.
A scientific stroll outwards leads to a weakness and the tune-up is on the far end.
An electronic coil controller that does away with the old points and condenser setup of old engines.
It was the new middle man in the nineties and another component that’s hidden in behind something.
You gotta give the engine boys credit for following tradition of their predecessors!
This one is behind the battery and mounted on the inner fender.
This item can be heat sensitive to some point as they need heat sink paste refreshed about every ten years under some climate conditions. Summer may be near you?
The climate behind the battery is stable enough but it can also be a place of moisture and corrosion so it’s with the time to do maintenance on it sometime during the life of the car.
The connectors pins need looked into and corrosion preventive applied.
An intermittent misfire is a heads up for things to get worse and the ignition system with its improvements of creating high voltages in nano seconds can require more credit for being flaky with any car and age is a factor as Mother Nature never relents.
Your not the first to travel down roads without having to pay dues for miles of less walking.
At least this car just doesn’t turn off and then ask you to call for help!
Well it can turn off but this car will not talk to ya, to rub it in!
🤑
Phil
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See if it can be narrowed down to one cylinder. Pull the plug wires one at a time.
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Hey Phil,
Thanks for the great tips! You're a Volvo guru and philosopher. You and Art really know all aspects of these great cars.
My crank sensor is an original, but the wire is good so I assume it's ok?
I've checked diagnostic tests, fuel injectors, idle air control solenoid are good, activating at least.
The TPS test had an after code of 3-3-4. I'm not sure what this is with this LH2.4. Any ideas?
I did a bit more testing.
With each injector wire pull, it runs much worse, and there are no stray sparks from the wires when I spray them with water. The sparkplugs all look clean and perfect combustion pattern.
One interesting thing, if I pull the #3 plug wire, the engine runs much smoother. If I pull #2 plug wire, the engine backfires a little.
Crank sensor? Timing belt?
(I replaced the timing belt around 2k miles ago, and retensioned it.)
Ideas?
Thanks!
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Hi,
I got your message and went into search here on the upper right corner with the code you got.
I have never seen this but then I keep my TPS and throttle plate in sync. It’s not something that goes wrong very much but the throttle plate can get very dirty with crankcase deposit via the flame trap system.
The search got me this : https://www.brickboard.com/FAQ/700-900/FAQPDFVersions/EngineOBDCodes.pdf#page9
It’s the thing that tells the computer to idle or take off. I talked about it as the transition zone maker.
Art Benstein and I have written posts on checking the throttle body and switch function.
I don’t think he has anything specific to setting this correctly on his site as most manuals have that covered.
Basically you want the throttle plate clean and closing all the way shut and the switch to click or make a change of state just when it opens just a crack.
“Change of state” means to either open or close or function in some way to do something when moved from a non energized resting mode or activation mode.
As I remember socket six operates and checks some components but I haven’t used it much to remember the details.
If you are getting a code you have triggered a change of state that it’s set to recognize to be out of perimeters of that diagnostic program.
If you are lucky it may have given you direction to 👀 into.
Like I said, the IAC only works if the ECU knows where or what the throttle is asking for.
Too much air at the wrong time affects cylinder mixtures and a misfire will occur.
The ECU is very fast in attempting to average out the exhaust reading from the oxygen sensor.
It cannot stop the misfiring but it will try to move the timing to eliminate any knock it might hear.
These cars are is some minds or terminologies are truly “self tuning.”
As far as the CPS the words original is a scary thought along with the spark coil relay, behind the battery, being never serviced.
The CPS goes bad in weird ways but I cannot say there is a code for it either.
There is more with the EZK system and things are being found out about them in the later 900 series.
Reading their posts has me thinking more about the CPS, the ICUs and their ECUs.
I think they may have a learning program that needs resetting.
I need to write up a recent experience on my 1993 that is similar, on another thread below, about the ECU.
They really get into the weeds that’s beyond any of my experiences.
https://www.brickboard.com/RWD/volvo/1688919/940/960/980/V90/S90/wouldnt_start.html
Thanks for the compliments but Art Benstein is the guru with a nice homegrown web site for 240s.
http://cleanflametrap.com/#links
Does the car take several turns of cranking in order to start or maybe harder to start than it use to?
Does the car race up and then idle?
You want 750 rpm. No foot pedal allowed or adjusting a throttle stop screw is allowed except to help stop the throttle plate from jamming into the throat of the throttle body.
Both the IAC and the TPS must close or click closed as they are spring loaded to return to a home position for the starting program.
Phil
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