|
|
|
I have a "92 240 that's been drivin me crazy for years. It's very hard to start when cold, runs pretty well when it's warm, but still stumbles on acceleration and hesitates just a bit at highway speed. If I hold the accelerator in, it won't start. I have to pulse the throttle to get it to start. If I leave my foot off the gas, or hold it in, it dies. I have to keep pulsing the throttle to keep it idling. When I can get it to about 2500rpm it runs well. If ambient temperature is about 60 or colder it is impossible to start. It is an LH3.1. I've tested everything I can think of, and replaced a lot of parts. I even replaced the ECU. I know it's a fuel problem, because if i squirt some gas into the throttle body, it will start just fine, and run until that gas is gone. The problem started shortly after I replaced the throttle sensor. It seems to run a little better with the throttle sensor unplugged. I've tested the throttle sensor and the wires to the computer. Everything seems fine. Fuel pressure is good. I'm about ready to sell it because I've just run out of ideas. I'm hoping someone on here has encountered a similar problem and can help me out.
|
|
-
|
|
Agreed with the others fuel pressure needs to be checked, but where I'd focus first is getting some detail on your pursuit of the ECT issue. Like more specifically, what does "out of spec" mean on the original sensor, in numbers? What are those numbers after replacement of the sensor, and can you confirm you used the correct dual element sensor? Don't you wonder why the ECU still says the ECT sensor is not returning the right info?
This chart of voltage vs temp is good for LH3.1 as well as LH2.4.
--
Art Benstein near Baltimore
"Good cheekbones are the brassiere of old age." -Barbara de Portago
|
|
-
|
|
Agreed that the ECT needs to be checked too.
An ECU that assumes a wrong (higher) temperature during a cold start would probably set the injector timing too low and with more fuel condensation the lower the ambient temperature gets, the more pronounced the problem becomes.
However, given the desription of "signal missing to/from coolant temp sensor" for the 1-2-3 diagnostic code (illuminating the check engine light), I would not expect a sensor that's functioning out of spec to trigger it. The range of operation is just too wide. Only a more catastropic failure, like a short or open, would IMHO trigger it.
Joshy mentioned "out of spec", not defective. Also wires were eliminated as a cause, which has me wonder if 1-2-3 is a self resetting code, or if it stays stored indefinitely until manually erased.
|
|
-
|
|
|
That's a good question, about the persistence of a DTC. I've dodged the question for the past 20 years by using a routine that includes removing all memory of previous settings. In other words, when I get done checking codes, I lift the fuse for a moment, which completely clears all codes and learned trim adjustments. There is no non-volatile memory in the ECU beyond the eprom. No need to wait any time to clear it by removing power, either, it is wiped in milliseconds.
I doubt the 3.1 ECU is any different in this regard, but things like that surprise me daily.
The cause of this trouble, in the past, where a new sensor doesn't clear the code despite wiring continuity checks, has come down to terminal push-back in the ECT sensor's connector, use of an LH2.2/2.0 sensor, or perhaps dirty contacts. Though I haven't seen it myself, there's also a possibility the sensor reference ground wire from the ECU to the fuel rail bolt isn't solid. It is very difficult to get folks to test the function in operation rather than testing individual components in a Sherlock Holmes process of elimination. Checking the voltage at the ECU connector is the only way to assure yourself all those bits are in place. That's what the ECU does.
--
Art Benstein near Baltimore
Never laugh at your wife's choices. You are one of them.
|
|
-
|
|
|
"Fuel pressure is good."
Did you measure this at the fuel rail and if so, what was the pressure?
Or did you do the usual test of disconnecting the fuel return line and see if there was a healthy flow back to the tank (which is a test I know from first hand experience is not very reliable, it really only tells you if the fuel pumps work and the FPR hasn't failed spectacularly, it can fail much more gradually in reality as I found out, it also only caused error codes very rarely!).
My first thought when reading these symptoms was FPR. My educated guess is that the fuel pressure on the rail is actually a bit low. Not by very much, but enough to upset the balance in cold conditions until the O2 sensor closes the control loop.
When just starting the engine, the ECU cannot make use of the O2 sensor data as it only starts to give sensible values after a minute or so. In the mean time the ECU applies a preset open loop injector timing based on engine temperature to approximate a correct mixture for a cold start condition.
This really needs the fuel pressure to be in the "ball park" as the ECU doesn't yet "know" from the O2 sensor if the mix was correct.
A somewhat high pressure will lead to no problem starting but right away the engine floods. I've experienced that on my previous 245. Likewise will a low fuel pressure lead to problems. Since during a cold start part of the fuel condenses on the inlet tract before entering the engine, it needs to be extra rich. If that enrichment doesn't take place, it's very hard to start, and the lower the ambient temperature, the worse it gets, as you noticed yourself.
FPR would therefore be my first suspect and I would swap it out with a known good one, unless of course you measured the fuel pressure as instructed by Volvo and found it to be within specifications.
|
|
-
|
|
|
It does sound like it's starving for fuel. Have you checked the fuel pressure at the injector rail?
Also, poor ignition can present itself in ways that you would swear are fuel related. You say it smooths out at 2500 RPM? Now that sounds like there is NO fuel shortage. How long since you've replaced rotor, cap, and spark plugs? What kind of spark plugs are you running? Are the cap and rotor Bosch or another brand?
|
|
-
|
|
|
fuel pressure is good. (can't remember the exact number, I think 40 psi) The spark plug wires are new. I haven't replaced the cap and rotor. I'm not sure what the spark plugs are
|
|
-
|
|
|
Hi,
I see you haven’t sold the car and haven’t blowed us off, yet!
I think you are past finding a quick fix, short of just unbolting the intake manifold and replacing the gasket under there.
Starting with that and working outwards and you will find a problem of lean mixtures.
You would be surprised how well the engines can run with a bad intake gasket because they are always self tuning.
I agree with Art, the IAC is fast, when their working correctly and spraying gas vapors around the outside is just going to get adjusted for!
I changed one not to long ago that had three cylinders leaking air.
I had been noticing the car would die and restart right back up and sometimes die again. It did this gradually worse over a long period of time.
Lasted until the engine warmed up enough to support combustion better and it ran fine the rest of the time! It was headed on that trail to be bad like yours.
During all this entertainment, again over quite a time, I did notice that there were oil stains collecting directly under the manifold runners except the last one.
Mainly because it’s to hard to see and the crankcase flame trap is there.
It always sweats a little on all these cars mainly from tired hoses, I think?
It’s opposite the exhaust so leakage goes unnoticed or ignored because there’s no smell!
Out of sight, out of mind!
If you notice oil down on the side of the red block, you can think it might be a head gasket seeping but when it’s higher up on the head, then, you have to scratch your own head? ((:)
How does oil travel upwards? Well basically, it doesn’t, but you might blame it on fan currents but IMO, that’s a scapegoat (phil)osophy now! (:)
Upon replacing my gasket I determined that the oil is coming from the bottoms of the runners themselves.
Crankcase Oil fumes are heavier than air and dropout on the bottom of each rather equally.
Every time the engine stops the oil vapor gets to soak in.
This vaporized oil carry’s all kinds of goodies not wanted in the crankcase.
One is moisture, of which, leads to form acids of all types. Chemicals love being in dilution as it’s an activator.
This attacks the gasket material and it softens and deteriorates. It must Dissolve it and it disappears right into the engine firstly!
Mine was just full of holes, like the finest bubbles of Swiss cheese and mashed out to death and cremated on site!
20 inches of vacuum volume is more than any vacuum cleaner can achieve because their not producing 20 to 50 horsepower, with any 110v electric motor.
A tiny crack width must cause more issues than you would think of, until?
Take a good look with a bright light under each intake runner to see trails of oil sweating down or puddling in crevices. If so, ITS leaking! One chance in four but mine had three! I was truly amazed!
The gasket was black throughout and really thin, so I’m not sure it was originally what came on the car from the factory.
I’ve seen pictures from Art posts and his looks brown or orangish like, but who makes it for Volvo then, is unknown? Computer colors vary too!
I put on Victor Reins and it’s twice as thick and gray when new. They must make their own material as their name’s letters are imprinted but cut out here and there.
I sure hope you give it a gander or a nut twisting party!
Phil
|
|
-
|
|
|
Hi,
Well, you seem to be a person who has some tenacity since this has been going on for years!
Now, if you could run a list out on what you have replaced might help us come up to speed on what might appear to be out of adjustment and not so much a part you have changed out.
How many parts, where?
Its good to know that you know you have a LH 3.1 as Many people don’t, so you have got that squared away. I hope you are correct?
The 3.1’s are a little bit “rare” but the major difference that it has is the throttle switch.
It is not just on and off but uses a variable potentiometer scale.
Lots of cars where going in that direction during this decade.
I don’t have one a 3.1 but a 1991,1992 and a 1993 their all clickers!
Your type of switch component has created an issue with many vehicles including my sister-in-laws 2002 Dodge pickup truck. I found the issue in 2010 after her husband passed.
Believe me, He loved to pump down on his ‘72 440 Charger!
It was for this very reason of carburetor drivers pumping the accelerator I deduced a possibility.
The problem that developed was the lack of steady idle speed mostly during warm up and a higher idle when it wasn’t needed.
Between that and moisture collecting inside the distributor cap, due to a lack of a simple vent hole, all her problems have gone away for years now!
She sold the Charger but kept the truck and her beloved 1973 VW bug!
Perseverance, IMO in this case, has been a mistake because mechanics have taken her wallet to the cleaners but she loves her High School car!
The 240 is a most superior car compared to the Air Cooled VW, IMO, but there was an investment difference in engineering in so many areas that makes the Volvo worth its salt!
You are wise to love it as we do!
As the other poster said about carburetors, they were simplistic enough, as a can within a can with holes for air to pass through.
Nothing like the smell of raw unburnt fuel in the morning or Robert Duvall’s, Napalm!
CIS was a step up as a controlled ignition bomb making affair too!
Pumping should never be done with fuel injected cars because it just confuses the ECU programs.
The next biggest bug-a-boo on these cars is getting the throttle plate held open by a tiny stop screw!
The plate has to be completely closed and the throttle switch set to its lowest or idle position so the computer knows that it’s what you want!
The ETC tells the ECU how cold the engine is.
This way the ECU lengthens the injector pluse width to enriched the mixture. “If”… this car has a cold start injector, it won’t come on above 60 degrees, so, this makes it very crucial that the ECT and the AMM talk volumes to the ECU. Without those two and the oxygen sensor the ECU is lost!
Any excess air or leakage behind the AMM is a big no-no! Splits in the accordion tube are the first thing to rule out!
In your case, to much air and the lack gas mixture is apparent.
The starting fluid proofs that other things are there electrically and mechanically.
To check the ECT circuit it should be done from the back of ECU plug by back-probing for a specific voltage variation on pin 13 and pin 5.
There is a chart to compare too. If you have a bad connection this will point back to the ECT though the wiring harness.
This is the sensor under the third intake runner.
Almost impossible to see but not hard to change out if you seal off the coolant tank to make the system air bound statically.
If it says your engine is up to operating temperature, it won’t work right when it’s cold but dies ok once you get going! A Classic explanation most of the time.
Art Benstein has lots of expertise in this area of the 240. He has dissected these cars, literally like a CSI mortician! He loves the word Necropsy.
He has my respect, for whatever that’s worth? (:-)
Another person is Dave Stevens as he writes in lots of details too.
There are several others that contribute to the board’s effectiveness.
They know of other quirks, that started in 1992, that can play with ones mind!
You might try a “shout out” on another titled thread. He might have things on his web site Cleanflametrap. Com. too!
Welcome to the Brickboard!
There is nothing better than going to the main men with your attitude that you will appreciate the help and their time.
We are all enthusiasts!
You have made a great start coming here!
Phil
|
|
-
|
|
|
I forgot to mention that I replaced the coolant temp sensor first even before I checked the codes. The old sensor was out of spec. it is still showing a temp sensor code, but I've tested the sensor and the wires and everything checks out. I've actually considered converting the car to LH 2.4, but I'll probably just sell it before I do that. I've checked for vacuum leaks.
|
|
-
|
|
|
Hi,
Well I hope you are not talking yourself into selling the car.
This whole thing sounds like lean air mixture to me.
That can start in several routine places and I’m sorry to hear that you have purchased so many bad AMMs. We’re they off yard cars or from rebuilders?
Either many are were good or a connection is bad to get that many bad ones in a row.
You say it runs well, warm, so there is no limp mode engaged for a bad AMM.
If you had a bad code for a ECT it should have cleared after you discharged the computer.
I suggest that you closed the battery leads together to do that for the whole car, in case there is an accessory that’s keeping residual power somewhere.
It can ten miles to bring up new codes but they are not designed to point directly at any one component. It’s a first level OBD unit before any more comprehensive standardized code system got developed.
Hard starting usually starts with bad ignition or lean mixtures unless your are flooding the engine.
The last one has been ruled out and the car runs decently.
Have you ever found moisture under the distributor cap when you cannot get it started.
Does it ever wet the spark plugs?
Have you ever changed the Crankshaft Position Sensor? Look for any cracked sheathing all the way down to the sensor behind the head!
It’s in a dark place just as bad as the ECT!
I understand why you chased the ECT and the AMMs if you believe those “shot gun blast” diagnostic codes.
Since you think you have to pump the gas pedal, this makes me want to think throttle body adjustment is off or a bad IAC valve sticking and any lines to it and coming back forward to the AMM.
If all that has been eliminated, then there, the intake manifold gasket that costs about $14.00.
It would be nice for someone to get your car cheap and then spend $14.00 to fix it!
If I didn’t already have six 240’s, I would slide right up behind you with a cashiers check!
I got a motorcycle once for a $100.00 because my grandpa always kept a hundred dollar bill in his wallet. He said there is always someone like you stunned with frustration and just says, “ I’m gonna sell this thing!
The bike I bought cost me about .035 cents to fix in 1970.
A bolt that held the ignition points “cam” down in place was broken and had jumped timing.
Probably the cheapest Harley Davidson part I ever bought!
Your case could be a simple something or other!
If it runs and looks decently and goes with dependability someone, somewhere is going to throw down some loose change for something user friendly!
Lately used vehicles are very popular as they don’t cost more than one month of home rental!
No interest or depreciation involved either!
My six cars collected over 40 years have cost me less than one lower or mid grade economy car and I could probably get half of that back if I sold them all!
I can spread them out for convenience. You cannot do that with only one car with each having a little different character. Almost like children I guess?
How long have you owned it or how many miles are yours and on the car?
Phil
|
|
-
|
|
|
Ignition.coil.🙏 A bad hall sensor in distributor. Also check your spark amplifier. The heat sink paste dries up on them and causes intermediate spark.
|
|
-
|
|
|
Have you checked the ecu for fault codes? see https://www.volvoclub.org.uk/faq/EngineOBDCodes.html#FuelInjectionandIgnitionDiagnosticCodesi
The FAQ guide says "LH2.4+", but I'm not sure if LH3.1 is different from LH2.4 in fault code retrieval -- someone on this forum will know.
It's best to check for codes before guessing and replacing parts. But guessing is fun when you're not the one paying for the parts. From what you describe, my first guess would be the coolant temp sensor or its wiring. But there are many other things it can be. Have you tried checking whether it starts and runs with the air mass meter unplugged?
|
|
-
|
|
|
I forgot to mention that I replaced the coolant sensor. I tested the resistance on the old one and it was out of spec. It still shows a temp sensor error code, but I've tested the new sensor and the wires and everything is good. I'm trying not to just replace parts willy-nilly. I'll test something; it's not quite in spec, I'll replace it and the problem isn't resolved. I bought several AMMs before I found one that works. The car runs a little better, but not much.
|
|
-
|
|
|
A '79 I bought a couple years ago had similar, (or worse) symptoms, since previous owner let it sit for 10 years. After replacing several parts, it showed no improvement, so I finally removed all the fuel-injection system and converted it back to a carburetor. It ran great & much simpler to work on.
|
|
-
|
|
|
That actually crossed my mind! But I'd just sell it before I'd do that much work.
|
|
-
|
|
|
I did it because it was a very low milage, one owner, pristine condition car. Actually the carb conversion is relatively simple and inexpensive.
|
|
-
|
|
|
"A '79 I bought a couple years ago"--
"Actually the carb conversion is relatively simple and inexpensive. "
FWIW
a 79 with a K-Jet mechanical FI, Bosch Electronic Ignition System (basically a step above points-n-condensor) and No computer is a very different animal compared to a 92 with Electronic FI, a computer controlled ignition with a flywheel triggered ignition via a Crank Postion Sensor... The ECU is the 'brain' that will look for that LH fuel system...a system that pulses the fuel injectors.
The K-Jet constantly streams the fuel--the amt is in realtion to the pressure measured out K-Jet system. More advanced than a Carburator, but basically the same idea.....When it comes to how involved it is to get the engine to function...when you turn the Key to Start---and then back to the Run position.
The OP, josh, wrote"
"That actually crossed my mind! But I'd just sell it before I'd do that much work. "
yah
|
|
|
|
|
