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GT_turbo
08-25-2007, 11:31 PM
Ok, I have looked many places and done many searches, but I just want others opinions on this matter. First off I have blown $300 on a new fuel pump and put and new fuel filter in my car so those are out of the question. My problem is that I will be driving and in totally random instances my car will just shut off. Up a hill, going 70 on the interstate, coasting at 40 mph... it just shuts off. I'm thinking ignition switch? Anyone have any clues???

And if your going to lock my thread or shut it down, please at least show me where my answers are because I have looked alot, and I cannot find it. I am sick of my threads getting deleted. I do search alot, some instances just aren't quite like mine.

Thanks.

GT_turbo
08-26-2007, 03:40 PM
*Update*

Ok I noticed driving the car today that is shut down coasting down the same hill that it shut down on before. It has never killed when the RPM's are above 2,000. Could this be a coil pack? I don't know what to think.

GT_turbo
08-27-2007, 10:35 AM
*bump*

Anyone???

timka86
08-27-2007, 11:15 AM
you probably have a loose connections somewhere. did this happen before you changed the fuel pump and filter? check connections arount ignition coils, or the big harness by the alternator that has all the wires for the fuel injectors.

timka86
08-27-2007, 11:19 AM
wait....

you're boosted, do you have it tuned? Maybe you're not getting enough fuel when coasting, but the turbo is still giving you more air.

(I didn't read the whole thread on how your turbo is finished)

This maybe a tuning issue, working out A/F ratio's.

GT_turbo
08-27-2007, 01:13 PM
Yeah I'm boosted. I got a tune done and the car runs really good most of the time. But sometimes it just shuts off. I'll double check those wires that you said, but it is very weird to me why it is doing this. I put a fuel pressure tester on it and its getting the fuel it needs.

Lab Rat
08-27-2007, 01:30 PM
Catalytic converter shut me down. It's hard to tell if it's clogged but Iwent thru everything before I found that.

GT_turbo
08-27-2007, 03:06 PM
First off, I have no cat, second of all this shutting down is no sign of a cat. if it was.

GT_turbo
08-29-2007, 10:56 AM
Ok, I am getting a better idea of the problem and when it occurs.
1. It only happens when it gets warm.
2. It shuts off ussually under 2k RPM's.
3. When I try to start it, right away it just cranks all day. If I wait 30 seconds it starts up every time.
4. No vaccum leaks.
5. Fuel pressure tested good, when it killed it had like 55 psi of fuel.
6. Obviously fuel filter is good because of #5.

Could this be a cranks sensor? I know there are 2, a 24x one and a 3x one if I am correct. Or could this be an ICM? Which one would be your guess?

Thanks.

Bryan
08-29-2007, 11:02 AM
I had a similar problem, it turned out a wire from the ignition module had come loose.

GT_turbo
08-29-2007, 11:03 AM
Ok, I am getting a better idea of the problem and when it occurs.
1. It only happens when it gets warm.
2. It shuts off ussually under 2k RPM's.
3. When I try to start it, right away it just cranks all day. If I wait 30 seconds it starts up every time.
4. When it starts it is hesitant, no misfires, but my A/F gauge reads lean at 50% on up throttle.
5. No vaccum leaks.
6. Fuel pressure tested good, when it killed it had like 55 psi of fuel.
7. Obviously fuel filter is good because of #6.

Could this be a cranks sensor? I know there are 2, a 24x one and a 3x one if I am correct. Or could this be an ICM? Which one would be your guess?

Thanks.

Sprucegagt
08-29-2007, 11:10 AM
How old is the fuel filter? Just because you have pressure does not mean you have good flow.

GT_turbo
08-29-2007, 11:19 AM
How old is the fuel filter? Just because you have pressure does not mean you have good flow.

Brand new, I replaced it before I spent $300 on the fuel pump, thinking this was a fuel problem. I have 55 psi. of fuel when it all the sudden kills, I'm sure it wouldn't be a fuel filter even if it was old, because I have 55 lbs of constant fuel AFTER the fuel filter, so the engine is receiving fuel.

Bryan
08-29-2007, 01:48 PM
Not sure if you seen my post since you posted right after I did but I had a similar problem that turned out to be a wire that came lose at the ICM.

timka86
08-29-2007, 02:03 PM
Not sure if you seen my post since you posted right after I did but I had a similar problem that turned out to be a wire that came lose at the ICM.

there is two wires that plug into the ICM, that run from the back of the block past the exhaust manifold, and since you boosted you prolly removed the manifolds and possible pinched the wire/wires, or they burned through touching the exhaust. The wires go to a crank sensor. something to consider.

It's only two wires, I believe yellow and blue or black(don't quote me), and they only run from the sensor to the ICM.

GT_turbo
08-29-2007, 02:37 PM
there is two wires that plug into the ICM, that run from the back of the block past the exhaust manifold, and since you boosted you prolly removed the manifolds and possible pinched the wire/wires, or they burned through touching the exhaust. The wires go to a crank sensor. something to consider.

It's only two wires, I believe yellow and blue or black(don't quote me), and they only run from the sensor to the ICM.

Oh yeah, yellow and purple, I remember those wires. I'm going to give em a good inspection tonight. She shut off twice on the way home last night. I sure hope thats the problem. I'll let you know as soon as I find out.

Thanks for the help.

GT_turbo
08-29-2007, 09:00 PM
No burnt up wires. Anyone think this could be an ICM going bad?

AaronGTR
08-29-2007, 09:48 PM
First off, I have no cat, second of all this shutting down is no sign of a cat. if it was.

:nono: No reason to go cat-less on a street car. The gain is negligible. Get a high flow to put in there.

Ok, I am getting a better idea of the problem and when it occurs.
1. It only happens when it gets warm.
2. It shuts off ussually under 2k RPM's.
3. When I try to start it, right away it just cranks all day. If I wait 30 seconds it starts up every time.
4. No vaccum leaks.
5. Fuel pressure tested good, when it killed it had like 55 psi of fuel.
6. Obviously fuel filter is good because of #5.

Could this be a cranks sensor? I know there are 2, a 24x one and a 3x one if I am correct. Or could this be an ICM? Which one would be your guess?

Thanks.


The crank sensors are 24x and 7x. The 24x is the one in the crank pulley and the engine only uses that for engine speeds up to 1600rpm. The 7x goes to the ignition control module and is used for ignition timing, and the ICM also converts it to a 3x signal for the pcm to use for crank position and engine speed.

It doesn't sound to me like this problem would be related to the crank sensors though. It might be a problem with the ICM. One vital question no one has asked... when it shuts down on you, does the gauge cluster and everything go off (full electrical shut off), or does the engine just stall (electrical still on but engine dies)?

GT_turbo
08-30-2007, 09:09 AM
:nono: No reason to go cat-less on a street car. The gain is negligible. Get a high flow to put in there.

I truely believe in getting the exhaust out of the turbo as quickly as possible, for under hood temps and temps in overall, Also I believe its just healthier for the turbo, because its easier on the turbo. It will then create more power.


It doesn't sound to me like this problem would be related to the crank sensors though. It might be a problem with the ICM. One vital question no one has asked... when it shuts down on you, does the gauge cluster and everything go off (full electrical shut off), or does the engine just stall (electrical still on but engine dies)?

When it does shutdown, all the lights stay on, headlights gauge cluster. They don't even blink, as far as I'm concerned. This is a weird problem. I am going to just go ahead and get a new ICM and see how it works. Does this sound like a good culprit of the problem?

Thanks for the help guys.

3x3
08-30-2007, 05:49 PM
Crank sensor relearn?

GT_turbo
08-30-2007, 06:23 PM
Crank sensor relearn?


How would I do that? or what is it?

AaronGTR
09-02-2007, 08:30 AM
How would I do that? or what is it?


It's a procedure that syncs the pcm with the crank sensor, so that the pcm is reading the crank pulses with the correct timing. You need a tuner or a tech2 to do it. You only need to do it after switching pcm's or changing the crank pulley, so you shouldn't need it. It wouldn't cause your car to just shut off either.

3x3
09-03-2007, 09:27 AM
It wouldn't cause your car to just shut off either.

Yes, it actually will. When I was NA it did and after I went FI it did. It would run fine for 10 maybe 20 minutes and shutoff and then other times it would run for 3 to 5 minutes. It would just die without any notice.

AaronGTR
09-03-2007, 04:46 PM
Yes, it actually will. When I was NA it did and after I went FI it did. It would run fine for 10 maybe 20 minutes and shutoff and then other times it would run for 3 to 5 minutes. It would just die without any notice.


Are you sure it was that or are you just guessing? Because there are a lot of people who have driven around a lot needing a CASE learn and their engines didn't just up and stall on them all the time. And NA or forced induction would have nothing to do with it either. Only thing that matters is if he changed the pcm or crank pulley.

3x3
09-03-2007, 06:01 PM
No I'm not guessing. The question we should be asking is if he pulled his motor for the turbo build? If he did it's very possible that the crank sensor was messed with.

AaronGTR
09-03-2007, 10:58 PM
Well, my car never stalled when I was driving it and it needed a case learn. I guess you're special? Mind explaining how it would cause that problem?

3x3
09-04-2007, 06:44 AM
I don't understand the question Aaron but I am talking from my experience as I'm certain you are to. The simple fact is I don't post on these boards, but if I do, it is to help, and I'm not implying you aren't. In the past my car has shutoff while driving several times. The first time was on a parkway doing 60-65 where it just shutoff and no it wasn't after installing the under drive pulley. The second was more of a cause and effect where the serpentine belt because of the supercharger cut into the lower rad hose just enough to cause antifreeze and water to leak onto the electrical wiring for the crank sensor. The resolution for both cases was to get a crank sensor relearn.

GT_turbo
09-04-2007, 02:54 PM
I didn't pull the motor when I put the turbo on. I this is such a random problem. It didnt do it for 3 days and all the sudden it did it today. Pull it over and start it up and im on my way. Its annoying. So I may need a relearn?

AaronGTR
09-04-2007, 09:57 PM
I don't understand the question Aaron but I am talking from my experience as I'm certain you are to. The simple fact is I don't post on these boards, but if I do, it is to help, and I'm not implying you aren't. In the past my car has shutoff while driving several times. The first time was on a parkway doing 60-65 where it just shutoff and no it wasn't after installing the under drive pulley. The second was more of a cause and effect where the serpentine belt because of the supercharger cut into the lower rad hose just enough to cause antifreeze and water to leak onto the electrical wiring for the crank sensor. The resolution for both cases was to get a crank sensor relearn.


Pretty simply I was just asking if you knew why needing a CASE learn would cause the engine to shut down because it doesn't seem to have that effect for anyone else. According to the service manual the 24x signal is only used for better resolution below 1600 rpm. The 7x signal from the crank ring is what actually tells the ICM when to fire the coils, so I don't see why the 24x signal being out of sync would cause the engine not to fire and die. I'm not saying I don't believe you... I'm just saying it doesn't make sense and I'd like more info before I start telling someone they might need a CASE learn because their engine is stalling.

GT_turbo
09-24-2007, 01:20 PM
Ok here's the latest. I got a new ICM and it still dies on me.

Does anyone know what else it could be? It never dies above 2000 rpm. I will be on cruise and all the sudden it will just shut off but the instrument panel lights are still on, so its not a bad battery connection. It kills every time I go down this long, 1 mile road, just coasting, everything will be fine and all the sudden the I have no power.

Any suggestions?

AaronGTR
09-24-2007, 10:21 PM
Did you try checking to see if the car needed a CASE learn like 3x3 suggested? I honestly wouldn't think that would be the problem, but since a couple people said they had similar problems related to the crank sensor you might as well check it out. You'll either end up fixing the problem, or not fixing it and eliminating that as a possibility. I can't think of anything else.

GT_turbo
09-26-2007, 10:15 AM
Why would you suggest a case learn, if you just got done arguing with him that it wasn't. I think my computer might be bad. That or it could possibly be a crank sensor, but I really dont think it would be that. I'm going to get a new computer.

LukeD
09-26-2007, 10:49 AM
I had this problem and it seemed to stop happening, I THINK, when I fixed my broken bypass actuator on the underside of the supercharger. Did you check that? Another thing to check might be the O2 sensors. I rememmber having a problem with that too on the other car, it didn't throw a code, still was functional but upon looking at it with a scanner, it was pegged all the way rich, causing the car to lean itself out. Maybe unplug it and let the car run without it to see if it still happens?

Edit: Wait you said turbo, so I'm not sure about that actuator comment for you then.

AaronGTR
09-26-2007, 10:59 PM
Why would you suggest a case learn, if you just got done arguing with him that it wasn't. I think my computer might be bad. That or it could possibly be a crank sensor, but I really dont think it would be that. I'm going to get a new computer.

Because, although I don't think that it would cause that problem, if it does need a CASE learn the car will still run better after, and if the problem isn't solved by a case learn you know that wasn't it and to look somewhere else. That's how many difficult to diagnose problems are solved... process of elimination. ;)


I had this problem and it seemed to stop happening, I THINK, when I fixed my broken bypass actuator on the underside of the supercharger. Did you check that? Another thing to check might be the O2 sensors. I rememmber having a problem with that too on the other car, it didn't throw a code, still was functional but upon looking at it with a scanner, it was pegged all the way rich, causing the car to lean itself out. Maybe unplug it and let the car run without it to see if it still happens?

Edit: Wait you said turbo, so I'm not sure about that actuator comment for you then.

Yep, he is turbo so he doesn't have a bypass actuator. He has a BOV and a waste gate. You might be on to something with the O2 sensors and the pcm tuning though. A calibration that was off enough from what a turbo car should use could certainly cause drivability issues. At this point it's anyones guess.

GT_turbo
09-27-2007, 04:51 PM
Yep, he is turbo so he doesn't have a bypass actuator. He has a BOV and a waste gate. You might be on to something with the O2 sensors and the pcm tuning though. A calibration that was off enough from what a turbo car should use could certainly cause drivability issues. At this point it's anyones guess.

It certainly has nothing to do with the "tune", because the car runs GREAT 99% of the time. The ONLY problem I have is that it randomly just shuts off as if you turned the key off. Pull over turn the key to the off position wait 10 seconds and it fires right up. The car has unreal power and it idles great. When you go WOT from a dead stop the tires just chirp a little on the initial acceleration, but as soon as the boost hits in first gear the tires break loose and spin till 2nd gear. I'm thinking more of a bad PCM more than anything.

AaronGTR
09-27-2007, 08:27 PM
It certainly has nothing to do with the "tune", because the car runs GREAT 99% of the time. The ONLY problem I have is that it randomly just shuts off as if you turned the key off. Pull over turn the key to the off position wait 10 seconds and it fires right up. The car has unreal power and it idles great. When you go WOT from a dead stop the tires just chirp a little on the initial acceleration, but as soon as the boost hits in first gear the tires break loose and spin till 2nd gear. I'm thinking more of a bad PCM more than anything.


That's always a possibility too. Could be a loose wire in a connector somewhere or a bad pin in the pcm connector. Could be a lot of things. Don't discount the possibility that it could still be the tuning though. Just because it runs great 99% of the time doesn't mean the tune is perfect... tuning is more complicated than that. It might idle great and might have great power during full throttle. It could also have a lean/rich spot or maybe not enough ignition advance in that low rpm/low throttle input area where it's stalling though, and when you're cruising in that area and suddenly the engine gets loaded (like going uphill) it can bog and possibly stall.

I'd agree that it's still more likely an electrical problem, but until you get a more clear indicator of where the problem is I wouldn't rule anything out.

GT_turbo
09-28-2007, 10:56 AM
We hooked a Wideband up to it and its right in the range that it is supposed to be. It is a weird problem thats for sure, I checked the battery connections and they are solid.

Sinister Perf
10-23-2007, 02:22 PM
Don't discount the possibility that it could still be the tuning though. Just because it runs great 99% of the time doesn't mean the tune is perfect... tuning is more complicated than that.

I sent another PCM to GT_Turbo to see if the problem was with the hardware (PCM internal) and so far he said he hasn't had this random shutdown with the second PCM.

Thru my conversations with GT_Turbo about this issue, he reported to me that if the random shutdown occurred and you didn't turn the key off but just tried to restart, the engine would just crank and not fire. Only after he turned the key off for 10 sec or so would the engine restart. Based on this fact, I deteremined the problem was most likely a PCM hardware fault and not tuning. If it was a tuning issue the engine should have restarted without first keying-off the ignition.

I have seen some weird things happen with PCMs over the years but this issue was the first one like it I have come across. But there is a first time for everything.

-ryan