My last thread got off the track due to multiple issues ( replaced fan motor, replaced in tank pump twice due to faulty new pump.)
This morning I was going to test the timing and noticed it is jumping around,from
gets steadier as rpms increase. I tested the timing on my 93 model and it is rock solid. What would cause erratic timing at idle?
I tested ECT per the Bernstein; 1.4v at startup 100*ambient, .517 when engine warmed up appx 180*?? ( Don't know how to properly measure temp at operating temp.)

Sounds to me like your ECT is OK based on your two voltage readings.

The dizzy wandering at idle: I noticed this before with the Hall-effect timing in an well-worn distributor. Feel for play in the shaft; if it feels normal, double check with the vacuum line to the ICU plugged. Agree it probably has no bearing on your stalling.

I recall having to deal with sticky idle air control valves with LH2.0 which are the same type used in LH2.2. Washing them out may not be enough. Go through the base idle and idle mixture procedure and be sure the throttle plate stop is set. Make sure the TPS is not only "clicking" but electrically closing at closed throttle. Idle stability is especially important with a clutch.

If you have a Shrader on the fuel rail, someone has done some mods. Cross your fingers they were all good mods and take advantage of the easy measurement, but keep in mind the PO may have been up the same creek before you.

"Bernstein." "Bouregard." LOL
--
Art Benstein near Baltimore

It appears autocorrect has become my worst enema.

Sounds to me like your ECT is OK based on your two voltage readings.
I changed it this morning because i was changing the intake gasket, and I had one. The old one gave the proper voltages.. I will save it
I am about to check for dist. wobble.
And replace the broken knock sensor.
I tested compression and all cylinders were good. And identical to each other.
ICU vac line has no leak.
Will check TPS elec. function.

Rack has a schraeder, so this may not be easy due to the PO doing unknow mods. I wonder if the proper AMM is installed.
The heated wire test was 3.0 ohms. Bentley says 3.5 to 4.0. Guess I need an AMM too.

PS I wasted two hours checking fuel pressure and swapping FPRs, and almost changed a fuel pump before I realized the new 20 dollar Harbor Freight Gauge was garbage. It would change 20 lbs. when held upside down! If you buy the kit, keep the hose with the Volvo fitting, and connect it to your HVAC gauges. The rest goes in the recycle bin.

No end in sight.

Bouregard burco

"And replace the broken knock sensor." Ahhhh

"ICU vac line has no leak."

Not suggesting you plug it to check for leaks. Suggesting you plug it to eliminate the vacuum influence on spark advance to see if that makes a difference in stability. The transducer could be sticky.

But... Broken knock sensor sounds like a better bet.

Still, I don't believe this is the stall reason. Rail has a Schrader.



"...new 20 dollar Harbor Freight Gauge was garbage. "

What, did it get dropped and the needle came loose?

Forget that ohm spec on the AMM. It is bogus. Yours should be an -007.
--
Art Benstein near Baltimore

An invisible man marries an invisible woman. The kids were nothing to look at either.

Not suggesting you plug it to check for leaks. Suggesting you plug it to eliminate the vacuum influence on spark advance to see if that makes a difference in stability. The transducer could be sticky.
Do you mean plug it and then test for the heat related stalling?

Still, I don't believe this is the stall reason. Rail has a Schrader.


"...new 20 dollar Harbor Freight Gauge was garbage. "
What, did it get dropped and the needle came loose?
The gauge looked fine. Needle was attached. With a vaac on it you could turn it and it would fluctuate 20 lbs. It was also very slow, VERY SLOW to react. Threw me for a lop until I realized it. Connecting the HF line to a HVAC gauge provides a better gauge, instant reaction, and the ability to relieve pressure.

Forget that ohm spec on the AMM. It is bogus. Yours should be an -007.
What do you mean by that?
The car has an aftermarket coil. AMM connector shows damage and tampering, and adjuster screw is visible.
I performed the hot wire test and there was no power being sent to the AMM white wire. Bad ECU?
It is obvious that many parts have been changed. I have to figure out how to get things back to normal.
I checked the distributor play by shaking the rotor. There is vertical play and I can rotate it slightly CCW.

Not suggesting you plug it to check for leaks. Suggesting you plug it to eliminate the vacuum influence on spark advance to see if that makes a difference in stability. The transducer could be sticky.
Do you mean plug it and then test for the heat related stalling?

Still, I don't believe this is the stall reason. Rail has a Schrader.


"...new 20 dollar Harbor Freight Gauge was garbage. "
What, did it get dropped and the needle came loose?
The gauge looked fine. Needle was attached. With a vaac on it you could turn it and it would fluctuate 20 lbs. It was also very slow, VERY SLOW to react. Threw me for a lop until I realized it. Connecting the HF line to a HVAC gauge provides a better gauge, instant reaction, and the ability to relieve pressure.

Forget that ohm spec on the AMM. It is bogus. Yours should be an -007.
What do you mean by that?
The car has an aftermarket coil. AMM connector shows damage and tampering, and adjuster screw is visible.
I performed the hot wire test and there was no power being sent to the AMM white wire. Bad ECU?
It is obvious that many parts have been changed. I have to figure out how to get things back to normal.
I checked the distributor play by shaking the rotor. There is vertical play and I can rotate it slightly CCW.

Hi Dave,

Sounds like you need a plan.

First, fix the knock sensor. No, I don't have the experience to say for sure it isn't the cause of the stalling, but I can imagine if its terminal is loose, the circuit is conveying false signal as it rattles to the ignition controller resulting in spark retard.

Then, check your AMM. It should have a Bosch part number ending in -007. That's the right part.

The point about measuring resistance is that it is misleading. It is meaningless. Bogus. Forget it. If you're skeptical, the technical details behind this assertion lie in countless posts you can search on testing AMMs. The only meaningful test is substitution with a known good part.

Finally, get your base idle and mixture set. If you follow the book using an LED test light to set the AMM mixture screw, you'll be doing the same thing you would do if you monitored the oxygen sensor output. Just keep in mind the book was written before high impedance multimeters were in common use at an auto shop. The idea is to have the feedback from the oxygen sensor correct the mixture roughly once a second at warm idle. That's what the LED tool tells you, or the voltmeter on the oxygen sensor switching from 0.2 to 0.8V.
--
Art Benstein near Baltimore

Deja Moo: The feeling that you've heard this bull before.

Oh yes. I do need a plan. Yours is a good one. First, I have to take a big gulp and buy a knock sensor. The only one I have located is from Advance Auto and is 200 bucks.
You dont think that the failure to heat the hot wire on the AMM points to a bad ECU?

"The only one I have located is from Advance Auto and is 200 bucks."""

ATLANTA ATLANTA ATLANTA
did you try them???

http://www.voluparts.com/

Yes I did. Thanks for the tip They have them new and used.

Those guys are great....The Last of the Line of bonafide ReCyclers.

I got an igniton switch (used) $40

An exhaust pipe - header to first muffler for a Non Cat B21 $100 (yes they had to be waiting for my call) :)

You are right. I spoke to them on Friday about a used knock sensor. It arrived on Monday.

Before you install it, I suggest you repeat your test with the timing light where, with the original broken sensor you saw the timing unstable during idling, and then compare after replacing the sensor.
--
Art Benstein near Baltimore

Birds are grouchy in the morning because their bills are over dew.

I will do that, but to clarify, I swapped the coils before the sensor arrived.
With no knock sensor at all, the car seemed to idle a little smoother, but not what I would call normal. I drove the car 22 miles at 70 mph x 2, and some city driving. I encountered no issues. It was about 85 degrees though. The horrible running and dying while hot problem I am having happened at 100 degrees in stop and go traffic. Today, I will test timing with no sensor, then install sensor and test.
I may test the burn off function, though I suspect if it was not working the AMM would be ruined by now?
Also, am I to understand that AMMs are very difficult to test? I have been offered a rebuilt Bosch AMM for 100 dollars, I could buy it, swap them, and keep one for a spare.

"With no knock sensor at all, the car seemed to idle a little smoother, but not what I would call normal."

The object of asking you to apply the timing light was to compare the jitter you saw when the broken sensor was connected, with what it is with your replacement. The benefit is others could use that test and symptom to identify the trouble you had. There's a third variation you've considered: Running with no knock sensor (disconnected).

If what I suspect occurs, you might see the jitter in advance when the broken sensor is rattling its connection, that is generating false signal to the ICU because of its intermittent terminal. I'd predict having no sensor at all, or your replacement sensor would show up as less jitter or variation in timing.

As for the AMM, you're correct, there's only one way you are going to test an AMM: Install the unknown unit in your already-working car. That's why we try to find an inexpensive one when we don't need one.

Don't assume yours is toast if you can't get the burn-off test to work. Suspect the test.
--
Art Benstein near Baltimore

I had no Monet to buy Degas to make the Van Gogh.

Update on my 88 240.
It seems the coil was the issue on the "hot stalling and dying issue". I have been driving it for a week now with no issues except the rough Idle.( Also, I received my knock sensor and installed it. A scientific conclusion is complicated by the temperature here has gone down from 100, to 85 degrees. I guess I could put the aftermarket coil back in and drive it for a while to confirm the coil issue, but of course I cant duplicate the 100 degree ambient.

I have still to electrically test the Idle switch. Will do this this morning.
Incidentally, I have determined this is a water car. There is sand everywhere, as high as the tops of the taillight covers, which would have flooded the ECU. Car is running good though.
I am debating purchasing a used ECU and AMM, and substituting them. Though this model ECU has a great reputation, I am pretty sure it was flooded. And it would be nice to have a spare AMM to carry on long trips.
Again, thank you and brickers like you for what you do.

The object of asking you to apply the timing light was to compare the jitter you saw when the broken sensor was connected, with what it is with your replacement. The benefit is others could use that test and symptom to identify the trouble you had. There's a third variation you've considered: Running with no knock sensor (disconnected).

Good point. I want to benefit others. I replaced the coil with a 1990 coil. The sensor wire was tied off, not rattling its connection. I drove the car appx. 50 miles with no issues, except still slightly rough idle. After receiving the sensor, I as you suggested, placed a timing light on it BEFORE, then AFTER installation. The timing seemed to remain the same with the exception of it wandered, advancing, for about 60 seconds after installation. Then timing was just as before. Computer adjusting?
Have not knock tested with hammer.
I am faced with buying and trying a 50 dollar used, or a 100 dollar rebuilt Bosch. ( Lots of questions like how do I confirm I am putting a good part on?)

Don't assume yours is toast if you can't get the burn-off test to work. Suspect the test.

I don't assume mine is toast. At this point in my life, I always expect operator error when I am the operator.
Today, it should be hot enough to see if the hot stall issue remains.

I don't assume mine is toast. At this point in my life, I always expect operator error when I am the operator.

I'm w you brother!

General rule I apply: If the test brings bad news, I blame the test. If the news is good, the test worked to perfection!
--
Art Benstein near Baltimore

"The absence of evidence is not evidence of absence"

If the test brings bad news, I say what did I do wrong!
Dan

I am thinking I may have missed my calling in life. Instead of concentrating on my school of shade tree mechanics, I should have started " The society of plausible deniability and self delusion."

" The society of plausible deniability and self delusion."

so when are you running for Congress....Or these days you qualify as a CandyDate for the 2020 election - "Leader of the Free World"

" Quick, I must find the way the people are going so I may lead them!"

If Bosch actually did the rebuild that might be a good idea. At least you will be able to see if your old AMM is bad. I have had a couple of Bosch rebuilds from the junk yard that have been reliable.

Generally generic AMM rebuilds have not been too popular with the BB.

Dan

Not sure if your resources will allow it, but if this knock sensor replacement was confronting me, and I could absolutely not find a used sensor, I'd re-terminate the shielded wire from the ICU to have the two-pin connector like those on your injectors and I'd fit the sensor from an LH2.4 application, attached with a bolt.

$200 is incentive for that bit of "extra" work.

"You dont think that the failure to heat the hot wire on the AMM points to a bad ECU?"

Edit: I did miss something. Describe exactly how you prepared for and performed the test. I have a feeling you might want to repeat this test, because if you're sure you did it right, and the burn-off has not been happening, perhaps your AMM's hot wire has accumulated a lot of baked-on dirt. This car didn't have one of those K&N oil-soaked foam filters on it, right?
--
Art Benstein near Baltimore

Brickboard members are the most likeable, smartest, and best-looking people on the internet. [Citation needed]

I'd re-terminate the shielded wire from the ICU to have the two-pin connector like those on your injectors and I'd fit the sensor from an LH2.4 application, attached with a bolt.
I would be all over wiring in a later model sensor, they are 1/3rd the price, and available, ( The 88 model is not)
The 88 has a single wire going to the knock sensor,( I noticed no shielding.??) How would I address the one wire 88 harness to the two wire later sensor?
$200 is incentive for that bit of "extra" work. I would rewire something to save 1/10th of that, if it works.
Describe exactly how you prepared for and performed the test. ( Hot wire )
I ran the already hot engine 30 seconds at 2000 rpm. Turned off the key, and placed my meter on the white wire of the AMM, and the batt neg. post. Twice.
No voltage. Maybe I was too slow?
I have a feeling you might want to repeat this test, because if you're sure you did it right, and the burn-off has not been happening, perhaps your AMM's hot wire has accumulated a lot of baked-on dirt.
I thought the test was to see if the ECU was sending the 12V burn off power. How would dirt affect?
This car didn't have one of those K&N oil-soaked foam filters on it, right?
No K and N filter.
Dave Burr near my wits end.

Hi Dave Burr,

Witt's End: A place in an old computer game.

It has been a long time since I've had an LH2.0 car, and I confess to never having one of those from the LH2.2 years in the 240, 85-88, but I thought I remembered the wire to the Volvo/Chrysler knock sensor was a shielded wire, with the shield being unused at the sensor end.

Just had a look at an old V/C control unit with the stub of its harness still in place. It is from the 83/84 B23 years, but aside from a different interface with the fuel computer for RPM, very similar. The wire to the knock sensor is not shielded. Just an ordinary brown unshielded wire.

This means, if I would take my own advice, I'd have to do more than just re-terminate the knock sensor lead. I'd have to replace it, all the way back to the ICU, and tap the shield into the ground wire on the connector. That's a bit more than I thought I was "suggesting."

I'm going on here, and speaking of going on, Phil is correct, I think, about needing to rev to 3K RPM for the burn-off test. Again, my experience is weak here. I've done this test on an LH2.4 car, just to see how it works, but not on the earlier cars. According to the book, though, it shouldn't matter; the function is the same across the hot-wire AMM product line. The function keeps the wire clean.

Try it again, like Phil suggests, and be sure before you go looking for another fuel ECU, which I believe will be a -554 in your car. Those ECUs are supposed to be bulletproof.
--
Art Benstein near Baltimore

Two fish swim into a concrete wall. The one turns to the other and says "Dam!"

At wits end,

I stood out of this mainly because Art knows way more about the electrics and the electronics ---- I know only what I've had to learn to contend with my own 'fault diagnosis'. I really haven't had any with my '87 (Volvo Chrysler...LH 2.2, 5sp---same as yours just a year older.
I've only replaced the AMM, which got cooked by the prev owner because of the failed thermostat in the AirFilter box.
The AMM symptoms were "stalling at at cold start-up, but ran fine after a few mins of warm-up(4 to 5 starts later. I got a re-built AMM from RPR(out of business) in 1997. I kept the old AMM as a spare, because I know its symptoms.

I did replace the Hall Sensor in the distrib, but that proved to be Not the source of the problem.
That has been it so far. Got the thing in 1997 with a 103K...220K now and 22 years. So aside from the first owner's daughter's years in college. I'm the second owner.

Ramble End.

My first Recommendation after reading this thread.
STOP>>>DO NOT GO ANY DEEPER INTO THE WEEDS.

++++++++++Get a working Knock Sensor+++++++++++++++++++++
Install and report back.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^6^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

You posted:


1)The car has an aftermarket coil.
Suspect Numero Uno after you install the new Knock Sensor and find No Joy there.

2)AMM connector shows damage and tampering, and adjuster screw is visible.
That is perfectly NORMAL. The cover on that CO adjustment screw was "tamper proof' and may never have been replaced... you had to drill two indentations into it so you could turn it out using Snap-ring plyers. the cap in mine has two small holes drilled.


3)I checked the distributor play by shaking the rotor. There is vertical play and I can rotate it slightly CCW.
That normal. You would know it if was wobbly.. I've only found one wobbly in al the cars I've owned and it was in a 1971 Peugeot.

____________________________________________________________
Your major disadvantage is in not knowing what the PrevOwners did.
*************************************************************************

Harvard 1932 hand-book for First Year Medical School Students.

"if you hear hoof-beats coming toward you, don't think zebras"

+Get a working Knock Sensor+++++++++++++++++++++
Install and report back.

That WILL be my next step! Thanks

Rock auto sells a brand new Bosch knock sensor for under $30. Im curious as to where the knock sensor is located on the 88 ?

The 88 at rock auto is $159 and $188 !! later models are dirt cheap.
It is located between the two water temp. sensors.

Hi,

That ridiculous for what is essentially something like a condenser microphone out of a tape deck.
I have seen those in electronic stores for prices of a small bag of peanuts.
Even a nice omnidirectional microphone for these karaoke bars aren't that much and the transmitt some awful harmonics at times! (:)

The one on our cars probably sends out a flat signal until a knock happens.
They have software tuned inside the ECU to read the band frequency or signal from it to be X to X.
It's when the signal suddenly changes in amplitude, from its flat line "normal" signal, that the ECU does anything while its up there "out of bounds."
Not much more than a sound detecting burglary alarm microphone tuned to that of glass breaking or a thud! Not all that elaborate IMO.
A detonation knock is quite loud from the short distance of a water jacket!
It says in the manual that tapping a hammer on the block will generate enough signal change.

Yep, I would leave those boys sitting on their sack of seeds too!
Too many other part sources, needing business, to be playing on their street!

Phil

Hi Phil,


Don't I recall correctly you bought the SAE book by Bosch Automotive Electrics/Electronics 1st edition? Section on Knock Control starts on p132.

On our cars the sensor is located in the block, not in the head with the temp sensors. The block has a blind tapped hole near the top between #2 and #3 cylinders.

The Chrysler sensor is one piece with a stud and single terminal referenced to the block's ground. The Bosch sensor requires a bolt and has two terminals, ground reference provided by the shield on its coaxial cable.

Both sensors are high-impedance ceramic contact microphones, much like the pickup on that record player you played your 78's on. Bosch calls it "a wide-band acceleration sensor with a natural frequency above 25 kHz." That makes it worth more money than a replacement phonograph cartridge. (smile)

They "hear" the explosions in the cylinders whether they are timed properly or not, but the computers they connect to know when to listen to determine it is a knock.

The Bosch computers (EZK in 89+) even know which cylinder knocked and can individually retard the spark.

--
Art Benstein near Baltimore

Who's there?

Hi,

Yes Art, I did buy that book you recommended.
There is a lot of good information in there, in fact it’s good it’s a book because I will have to reread that part that you just put out there so eloquently.

I did not let a whole bunch of that sink into my head, I think? (:)
There is not much you can do with fixing it, as that whole system is out of our hands and technically it’s over this persons head!
I boiled it some and let it simmer with other ingredients from my life’s experiences.
I got the grasp of it and placed it over in the corner of my brain, where a lot of other things reside to mull around. (:)
It’s in that area of “background of data” of a mind, that the subconscious uses to arrive at some conclusion and you wonder “ Where did that come?” You ended up there with a reasonable explanation.

If you do it enough times, some people call it a “conclusive answer!”
Almost like a jury trial!
The more heads, the better can be the BrickBoard!
(:)

Phil

Try it again, like Phil suggests."Those 554 ECUs are supposed to be bulletproof."
I heard they were bullet proof. I will try the test again at 3000 rpm +.
I found a used hopefully good knock sensor for 50 bucks.

Thanks.

Hi,

Just a tidbit here on the burn off of the hot wire!

The ECU has to see the engine rev up over 3,000 rpms in order to trigger that part of the program on shut down.
From what I have read, it is set that high to reduce the number of times it will heat the wire, but at the same time, insure that it will get the treatment after a period of running.
It does not say for how long or how many times it must go over the 3,000 mark, but it must!

3,000 was chosen as a good place because it is “considered” to be rather difficult to drive the car under 3,000 with a stick.
This is still to be low enough to catch cars with an automatic transmission though!


Edit:
TedV was the one with the bad AMM


Phil

Thanks, it is unlikely that I reached 3000 rpm in my driveway. I will test it again with a tach......... and earplugs.

I have an 87 with the same ignition set up. With a timing light on the crank pulley with a drop of white paint on it and on the overhanging plastic scale 0 6 12 degs -- at idle there is a minor flutuation - so not absolute steady on the 12degree mark, but averaged out I can set the timing.
As Phil mentioned, possibly the CPS system on your 93 is stable to a degree at idle with a timing light...but then you can't adjust the timing with that Ignition system.

But more to the point--- are you asking for help figuring out 'why it dies when Hot' or about the idle flux

If so the Idle fluxes -- red herring for the "Dies When Hot" problem.

Didn't follow your last thread. R you the guy who posted that the AMM was bad after all?

Yes the idle is a nuisance, but the dying and running bad when hot is the more serious problem. Strangely, a 5 minute cool down makes the problem go away.

No, I am not the bad AMM guy, but I will be testing the AMM today though.
That may be my issue.
Thanks

Hi,

Yes, I noticed your thread got off track. It happens!

Does this visual timing observance with a timing light only doing it when idling?

The timing jumping difference between the two cars would not be uncommon, if the one that is jumping around, is miss firing from weak ignition components or improper mixture to the cylinders or one in particular.
Have you ever performed a compression check?
Read the deposits on the spark plugs for changes.
Have you ever replace the main coil wire or rotor button?

Both cars have self tuning systems. They do derive their input values differently of where TDC is and have dated ignition components using separate manufacturers. 1989 was the shift point.
A knock sensor is used on both systems and that will pop around timing under extreme situations of loads. Idle speed roughness shouldn’t count.
With these two systems compared, there is not going to be a large enough variation that you could be seeing in any appreciable amounts, because you would have the laboratory type test equipment.

The improvement made with a CPS is suppose to better in holding accuracies of locating the crank at various speeds and not simulating it’s location with a reluctor wheel and distributor gearing slack!
Is your timing belt adjusted up to snuff on the cam and the distributor?

The 1988 car is a LH 2.2 has a hall sensor in the distributor. If the shaft in it were worn enough, that you could shake it, then I would then say, you have a problem with reluctor clearances.

That’s about as far as I can think of why you are seeing the timing marks jumping.
Always Rule out the ignition first!
Air leaks and mechanical condition of the engine, Do go hand in hand.
The fuel management system is the last resort, believe it or not, because it is running so close to correctly.
After all that you might substitute the AMM’s around. It is the only true test after you have gotten everything else nailed down in your mind as good as you can get it to be.

It will be interesting to find out what it is!

Phil

Does this visual timing observance with a timing light only doing it when idling?
It smoothes out with an increase in rpms.
Have you ever performed a compression check?
I will do that today.
Have you ever replaced the main coil wire or rotor button?
New Bouregard wires, rotor, and cap.
A knock sensor is used on both systems and that will pop around timing under extreme situations of loads.
Yesterday I replaced the ECT and intake gasket even though I think the old ones were fine. During this, the knock sensor either fell apart, or I broke it. Maybe it was bad, I had not checked.( Caching,caching, and wait for a replacement. )
The improvement made with a CPS is suppose to better in holding accuracies of locating the crank at various speeds and not simulating it’s location with a reluctor wheel and distributor gearing slack!
Is your timing belt adjusted up to snuff on the cam and the distributor?
I believe so. I replaced the timing belt and roller / tensioner.
The 1988 car is a LH 2.2 has a hall sensor in the distributor. If the shaft in it were worn enough, that you could shake it, then I would then say, you have a problem with reluctor clearances.
I will check the dist. shaft play today.
Always Rule out the ignition first!
Air leaks and mechanical condition of the engine, Do go hand in hand.
The fuel management system is the last resort, believe it or not, because it is running so close to correctly.
After all that you might substitute the AMM’s around. It is the only true test after you have gotten everything else nailed down in your mind as good as you can get it to be.
I noticed that the cover is missing to the amm adjustment screw, so I will be testing it today as well.Maybe bad AMM, maybe wrong AMM. I am realizing this car was previously worked on by a jackleg mechanic, ( or maybe I should say ANOTHER jackleg mechanic.) so I really need to verify a lot of functions. There is a schraeder on the injector rack, which I thought was not on a factory 1988 240.?
It will be interesting to find out what it is!
It will be an enormous relief to me and my wife to find out what it is.

Thanks for the help.