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Car Stalls while driving

E

EddieA

New member
2002 Pontiac Grand Prix
3.8L - unmodded
180K miles


Please read entire description, Im sure there have been similar post to this issue since the 3.8s are notorious when it comes to stalling. So here's the situation.

Car stall randomly, it can be while driving on the freeway foot on the accelerator, or sitting at a light idle. When car dies, I get all indicator lights as if i just put the ignition switch in the "on" position. I do NOT get a "service engine" light when this occurs, this being said there are no codes to be read.

Thus far I have;
Checked fuel pressure - good at 45 psi
Replaced the crank position sensor
Replaced the cam position sensor
Swapped ignition control module (with known good one)
Swapped coil packs (with known good ones)

Generally, from what I have read, the crank position sensor is the culprit. In this case, with it being replaced already Im second guessing myself.

What i do find odd is that I am unable to induce a PCM/ECM fault. I have pulled a plug wire which should give me a "service engine" light but did NOT. I have also pulled multiple sensors as well as an injector cannon plug, still unable to induce a "service engine" light. The "service engine" light does work as I am able to turn it on/off with the use of a 2 way code scanner (Autel Maxidas).

Could I have a bad PCM/ECM? Could this be the issue to my stalling randomly? Is there anyway to test the component?

Help please.

EA
 
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i was getting crank sensor, icm and another icm code from a bad harness, crank sensor to icm. the whole harness was falling apart, the insulation was all dried out and cracking off.

look close at the black wire with white strip, its all messed up under where you see the bare wire.
001_zpsi1taot6d.jpg
 
visual inspection of wiring, and pins at cannon plugs look good. I have not wrung out the wiring as generally your more susceptible to component failure before wiring failure. Additionally where would I start, as I have 2 issues that could be related to 1 component - the stalling of the car and the inability to induce a "service engine" light.
 
To ScottyDogsg.....your getting a code and an "service engine" light unfortunately, Im not getting either.
 
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Random stalling won't set the check engine light.

Mainly because something is telling the computer to either stop firing the injectors or stop sending spark. So when that signal or communication is lost, the PCM thinks that you just turned the key off and it does what it's told. It'll just stop doing the command and "stall" the motor.
 


un plug the maf then start the car, that will for sure set the cel off.

if it dont light up theres the chance the bulb burnt out, or the owner broke the bulb.

either way get it scanned pending codes dont set the light, and if the lights busted, you could have codes and dont know it.

if your scanner just flat out wont communicate with the car, check the cigg lighter fuse. it powers the obd2 port.
 
Fivefingerdeathpunch said:
Random stalling won't set the check engine light.

Mainly because something is telling the computer to either stop firing the injectors or stop sending spark. So when that signal or communication is lost, the PCM thinks that you just turned the key off and it does what it's told. It'll just stop doing the command and "stall" the motor.
Click to expand...

Again.... nothing appears to be setting off the "SEL". I can pull a plug wire, car will run rough but no "SEL". I can pull an injector cannon plug, no "SEL". I've disconnected multiple sensors including the MAF, no "SEL".
 
ok then, the bulb dont work, so get it scanned already so you know what your working with.

have you scanned for codes? yes or no?
 
ScottyDoggs said:
ok then, the bulb dont work, so get it scanned already so you know what your working with.

have you scanned for codes? yes or no?
Click to expand...

EddieA said:
Im sure there have been similar post to this issue since the 3.8s are notorious when it comes to stalling. So here's the situation.

Car stall randomly, it can be while driving on the freeway foot on the accelerator, or sitting at a light idle. When car dies, I get all indicator lights as if i just put the ignition switch in the "on" position. I do NOT get a "service engine" light when this occurs, this being said there are no codes to be read.

Thus far I have;
Checked fuel pressure - good at 45 psi
Replaced the crank position sensor
Replaced the cam position sensor
Swapped ignition control module (with known good one)
Swapped coil packs (with known good ones)

Generally, from what I have read, the crank position sensor is the culprit. In this case, with it being replaced already Im second guessing myself.

What i do find odd is that I am unable to induce a PCM/ECM fault. I have pulled a plug wire which should give me a "service engine" light but did NOT. I have also pulled multiple sensors as well as an injector cannon plug, still unable to induce a "service engine" light. The "service engine" light does work as I am able to turn it on/off with the use of a 2 way code scanner (Autel Maxidas).

Could I have a bad PCM/ECM? Could this be the issue to my stalling randomly? Is there anyway to test the component?

Help please.

EA
Click to expand...

There ya go Scott first post.
 


does the tach ever drop to zero while driving? or right before it stalls?

in what way does it stall? like it ran out of gas sputtering as it dies? or flat line dead all of a sudden?

it could be a messed up maf too. un plug it and drive it for a day or two, but dont beat on it. if it runs better with it unplugged the maf is bad.
 
ScottyDoggs said:
does the tach ever drop to zero while driving? or right before it stalls?

in what way does it stall? like it ran out of gas sputtering as it dies? or flat line dead all of a sudden?

it could be a messed up maf too. un plug it and drive it for a day or two, but dont beat on it. if it runs better with it unplugged the maf is bad.
Click to expand...

It goes flat line dead all of the sudden. No sputter, definitely not fuel related. Car runs perfect, WHEN ITS RUNNING, as its well maintained. Couple of things regarding your MAF suggestion..
First, wouldnt i have a bit of flux in the RPMs? Secondly, if it were a bad MAF, wouldnt this be captured and produce an SEL by the PCM/ECM?
 
some times a bad maf acts up and does not set a code. some times you can tap the top of the maf while its running and it will either idle right, or become rough running, tap it again it goes back the other way.

bad maf can cause stalling, and odd shifting too.
 
When the car is running it idles perfectly. Shifting has been perfect too. Ill tap on it, as i have done everything else, BUT..... as mentioned in my original post..."What i do find odd is that I am unable to induce a PCM/ECM fault. I have pulled a plug wire which should give me a "service engine" light but did NOT. I have also pulled multiple sensors as well as an injector cannon plug, still unable to induce a "service engine" light." The MAF Sensor being one of the multiple sensors.

So back to my original questions.... Could I have a bad PCM/ECM? Could this be the issue to my stalling randomly? Is there anyway to test the component?
 
it could be the pcm. never know, or a chafed wire some where.

common places are the wires to the pcm. and the metal loop on the dog bone that holds the wire harness.

when you turn the key to run, not crank, just run and all the dummy lights light up, the check engine light is out at that point too?
 


When I place the car to run all the dummy lights are on as per the manual. Im half tempted to buy into AllData for wiring schematics. In my line of work, wiring is usually the last thing we go for.
Guess I did forget the important stuff....

2002 Pontiac
Grand Prix
3.8L - All stock
180K Miles
 
id give your wires a good looking over. then maybe its the pcm. i cant be 100% on that tho. but odd things can happen with electrical stuff.
 
Gnerally a fault needs too be present for two drive cycles before a CEL is set, first drive cycle sets a pending code and then on the second drive cyccle if the fault still exists a CEL would be set.
Never rule out fuel pressure until you've actually seen what the pressure is when the car is stalling, a sudden fuel pressure drop would not cause the car to "sputter" it'll just stall and would not set a CEL
 
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