Author Topic: Warm start stall (Read 17379 times)

JHZR2 · « **on:** July 30, 2008, 08:26:24 PM »

Hello,

My 91 318i runs like a top, good power, good mileage, etc. It always starts cold. However, when I start it hot, i.e. after using it for a while, and let it sit from 30 seconds to an hour or two... then it will start up and immediately, gracefully go right back to 0 rpm, i.e. stall. No odd noises, and this will happen multiple times.

If I give a little bit of gas, the car will stay running very easily, and then idle just fine - rock solid stable. And its not much gas, just 1500 RPM for about 5 seconds is all it takes.

The car starts, runs, idles, etc perfectly otherwise... There is no clear issue that exists. The fuel pump is recent, as though it wasnt exhibiting any problems, it was noisier than I thought it should be, and the connection was a bit flaky...

Any thoughts as to what it could be???

Thanks,

JMH

AcSchnitzer318is · « **Reply #1 on:** July 30, 2008, 09:51:05 PM »

Welcome to the club... been dealing with this since I bought my car in Feb. Changed all kinds of parts, but still no solution... keep us updated if you figure it out.

Cobra Jet · « **Reply #2 on:** August 01, 2008, 11:38:54 AM »

Two things you can try:

1) remove the ICV valve and clean it - if you have never done it, it's possible it's carbon'd up inside. Get Brake cleaner and squirt a liberal amount inside, let it side for about 10 mins, shake it out and repeat 2 more times. After it's dry, then squirt WD40 inside of it, reinstall and your idle should be alot better than previously. The ICV regulates the air going into the engine for idle speed, driving, etc...

2) coolant temp sensor is malfunctioning, thus sending bad data to the DME. If the sensor is not able to determine or sense the correct temps for hot, warm or cold drivability, once the data is sent to the DME, the car could be dumping fuel or leaning out, which will affect drivability and hot/cold starts.

AcSchnitzer318is · « **Reply #3 on:** August 02, 2008, 12:44:13 PM »

Here's a link to the other thread with more things you can try. None of us have figured it out yet though... I think there are 3 or 4 of us working on it. http://www.m42club.com/forums/showthread.php?t=6077

EN318isPDX · « **Reply #4 on:** August 04, 2008, 06:41:01 PM »

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DMNaskale · « **Reply #5 on:** August 09, 2008, 11:02:22 AM »

Hi, I am new and this is my first post. I am sort of relieved to see that I am not crazy and that other people are having the same problem. My wife drives a '91 318i sedan, and it has been doing the warm start stumble for as long as we have had it, a few years now. She loves the car and just considers the problem to be part of the cars personality, however as a dedicated car geek who does all my own work I find it to be like a rusty knife thrust into my soul. When we bought the car I replaced just about everything under the hood as far as sensors and hoses goes, and I have swapped in different coils, ECUs and AFMs and replaced the ICV and FPR in chasing the problem. Nothing has ever made a difference. The car always starts fine and drives great, until you shut it down and then attempt a warm start. Then it starts OK, but the idle will get rough and it will eventually stumble and die if you don't give it some pedal, sometimes a whole lot of pedal. You can keep it going this way, and after roughly 45 seconds it starts to run fine again until the next warm start. I eventually gave up trying to fix it and intalled a little button and a timer-relay that sends a bogus cold reading to the engine temp input to the ECU for like 30 seconds, this will help it run somewhat better until it clears up on its own. I am to the point that I am considering ripping the Motronic entirely and going MS2, but that is a lot of work on a car that is just a commutermobile and is otherwise stock. I have thought about welding in another O2 boss and temporarily putting in a wideband O2 to help figure out what is going on, I may still do this someday.

Daryl

'91 318i sedan, and a bunch of E28 535s.

Andrew546 · « **Reply #6 on:** August 11, 2008, 08:30:16 PM »

My dad and I have been trying to figure out what the problem is with the warm rough start for a few years. We talked to a mechanic that we get some parts from and he mentioned that a fuel injector might be leaking extra fuel into one of the cylinders and making it idle rough until the extra fuel burns off. This seems to be good explanation for it, but we couldn't find any visual signs that one might be bad when we took it apart today. We just ordered 4 injectors. Hopefully this will help. We will probably install them on Wednesday. What do you guys think?

DMNaskale · « **Reply #7 on:** August 11, 2008, 09:38:30 PM »

Quote from: Andrew546;54718

My dad and I have been trying to figure out what the problem is with the warm rough start for a few years. We talked to a mechanic that we get some parts from and he mentioned that a fuel injector might be leaking extra fuel into one of the cylinders and making it idle rough until the extra fuel burns off. This seems to be good explanation for it, but we couldn't find any visual signs that one might be bad when we took it apart today. We just ordered 4 injectors. Hopefully this will help. We will probably install them on Wednesday. What do you guys think?

At least in the case of my car, I don't think a leaky injector could be the problem because the car will eventually stall if it is allowed to idle without touching the gas. One cylinder burning off extra fuel would not slowly kill the engine. Does your car stall if you let it idle after a warm start?

EN318isPDX · « **Reply #8 on:** August 12, 2008, 11:36:38 AM »

A leaky injector could cause this but it would not only happen on warm.. it would happen most of the time. My guess would be the coolant sensor or vacuum lines. If not that just check the fuel pressure coming out of the fuel filter. Could be starving for fuel.

EN318isPDX · « **Reply #9 on:** August 12, 2008, 11:45:37 AM »

Quote from: Andrew546;54718

My dad and I have been trying to figure out what the problem is with the warm rough start for a few years. We talked to a mechanic that we get some parts from and he mentioned that a fuel injector might be leaking extra fuel into one of the cylinders and making it idle rough until the extra fuel burns off. This seems to be good explanation for it, but we couldn't find any visual signs that one might be bad when we took it apart today. We just ordered 4 injectors. Hopefully this will help. We will probably install them on Wednesday. What do you guys think?

I replaced my injectors even though i wasn't 100% sure they were bad.. I gained about 10mpg just by replacing them. It was more than worth it even though it didn't fix my stall issue. I am very happy that i replaced my entire fuel system.

Andrew546 · « **Reply #10 on:** August 12, 2008, 02:28:02 PM »

The fuel injectors were delivered today.

Quote

I replaced my injectors even though i wasn't 100% sure they were bad.. I gained about 10mpg just by replacing them. It was more than worth it even though it didn't fix my stall issue. I am very happy that i replaced my entire fuel system.

That makes me feel better about spending $250 even though it won't fix the problem.

Has anyone who had this problem successfully fixed it by doing any of the things mentioned? It seems like nobody has had any luck.

EN318isPDX · « **Reply #11 on:** August 12, 2008, 02:55:08 PM »

Quote from: Andrew546;54738

The fuel injectors were delivered today.

That makes me feel better about spending $250 even though it won't fix the problem.

Has anyone who had this problem successfully fixed it by doing any of the things mentioned? It seems like nobody has had any luck.

You should have shopped around and tested the fuel pressure before spending 250.. 222 for a fuel pump on rockauto, same price as an employee gets the bosch for at my local dealer. I paid 26 per injectors off rockauto.

I've learned from buying tons and tons of parts that even if it doesn't fix your issue it prevents one in the future. Why not replace an o2 sensor if you dont know the mileage on it?

AcSchnitzer318is · « **Reply #12 on:** August 12, 2008, 06:24:00 PM »

Quote from: Andrew546;54738

Has anyone who had this problem successfully fixed it by doing any of the things mentioned? It seems like nobody has had any luck.

Nope no luck. Just fixed my exhaust leaks and still no luck. Even worse I stopped by a dealer who had a low mileage ~150k 318is 91 and it started right up and idled awesome. Sounded way healthier than my 34k motor. Pissed me off

For some reason my engine sounds way raspier than the other one did.

I'm having my mechanic pull the valve cover and check the timing to see if it is in spec for the Delta regrinds. I'd switch back to stock cams if I thought it would help... but so many ppl with stock cams have this exact same issue. Becoming a real thorn in my side.

achtungE30 · « **Reply #13 on:** August 18, 2008, 10:15:45 AM »

This problem has plagued me for nearly 2 years now as well.

It seemed to have begun immediately after I cleaned out my ISV and AFM with TB cleaner and attempted a hot air intake install. I've attempted and done the following with no joy.

Tried a known good AFM
made sure fuel pump connections were tight
(fuel pump 3 years old)
replaced all the hoses below the intake manifold
fuel injection cleaner
replaced with known good FPR
went back to stock airbox

just wanted to add this in to this official thread - i've almost come to accept my old e30 likes make me look bad in front of a group of people as it always does this only in front of an audience, not when we're alone

AcSchnitzer318is · « **Reply #14 on:** August 18, 2008, 11:33:02 AM »

^LOL consider yourself lucky then, because mine does it all the time... unless I let her sit there and idle for 2 minutes before trying to drive off. LOL it pisses ppl off in busy parking lots. "Why aren't you pulling out already!!!!?

"