2001 Pontiac GP - 3.8L Dies Every 46 Seconds? FIXED

[GEEPINCJ7]

I have a 2001 pontiac Grand prix 3.8 here that is driving me crazy. It dies every 46 seconds on the nose. It will start right back up and then die 46 seconds later.

I am getting no codes and nothing obvious on the data screen when the car dies. The owner has worked on it and It has been at 2 other shops. They have replaced a lot of parts but it still dies. I have not replaced any parts yet because it seems everything that can be replaced has been. The fuel pressure does not drop when the car dies, and the pump runs for 3 seconds after it dies. The spark does not seem to cut off when it dies. I cannot tell for sure if the injectors cut off. I am stumped. I thought maybe the security system was cutting off the injectors but I see no evidence of that on my scan tool data screen. Here is a list of the parts that have been replaced..

ecm
bcm
mass air flow
ignition module
cam and crank sensors
idle valve
map sensor

This is driving me crazy because I have never seen a car die like clockwork every 46 seconds. I am not sure where to go from here so I am hoping someone has seen something like this before. Thanks in advance

[Rich]

Um, just a crazy question...does it have an automatic start on it? Wonder if it does. I know they be programmed to allow the car to run a set amount of time and then shut off. I don't know why it would allow 46 seconds, but just a thought.

[liljoe]

Does it rev up during the 46 seconds, if you have it at a higher RPM does it still die, does it die smoothly or get skippie before?

[steven kiser]

have seen some real fancy theft deterrents in the past. i would look carefully in the harness around the ignition switch and pcm. see if there is an aftermarket remote starter in it. if so see if the ring had been removed from the cylinder and a key taped across it as a reader for the remote. if the answer is yes to any of the above then that's where i'd start. i've seen transistors installed in line to bypass the reader look for these. a pattern shut down usually is the anti theft module which i believe is a separate module.

[GEEPINCJ7]

No alarms and no remote starts. I have checked closely and I see no evidence of any ever being installed. I have tried to rev it up at the 45 second mark but it will still die. I cannot rev it up and keep it running. I am starting to think it has something to do with the car going into closed loop. However, The car is in closed loop 15 seconds after it starts. I am in the process of checking the o2 sensors to see if they are causing problems when the car goes into closed loop.

[GEEPINCJ7]

I have had a bit of a breakthrough. I noticed that the canister purge solenoid was new so I checked the history codes and sure enough it had a previous code for an evap problem. I pulled the line from the tank to the solenoid off and noticed raw fuel at the solenoid. I started the car and sure enough at the 44 second mark the valve opend and pulled raw fuel in from the tank and made the car die instantly. So I am thinking my canister on the tank is bad. I am going to drop the tank and see what I can find out.

[liljoe]

Bingo for you, you are the hero today!!!!!!

[steven kiser]

ahhhhh, i see a combination of charlie chan, sherlock holmes, dick tracy, barnaby jones, kojak, etc. good job.

i'm in the habit of asking for all orders from other shops or part stores (for do it yourselfers) when i have a "group effort" towed into my shop. another thing i do, and i strongly suggest this to you, since you're getting to the bottom of this and will succeed in resolving the issue at hand, everything and i mean everything that has been previously installed in other shops to resolve this issue be replaced with your quality parts. it doesn't matter what the customer says now, he's just as frustrated as you and just wants the car back.

we as owners, mechanics, human beings know that without a doubt when a part that was installed at a prior repair shop to try to fix the issue fails it's coming back to you. no matter what you do or say to try to convince the customer it isn't your issue or fault since you're the last one to work on it it's your issue. if the p.c.m. fails and it's taken to the shop that installed it do you think for a second that you're not going to get thrown under the bus.

this happened to me once. like this car, it had been to four other shops and it looked like a dart board with having so much thrown at it. a corroded ground wire at the t/stat housing was the culprit. happy customer left and then came back with a list of issues. i found plugs were gapped incorrectly, timing off, rattle under dash from an improperly mounted p.c.m. etc. you know what happened don't you. they had taken it back to the previous repair shop and was told that since i had worked on it all the associated warranty from what they did was voided. back in my ball park. if i didn't resolve all the issues then it would be me that got bashed by this person. for this reason alone i will insist i replace everything that was done prior to me working on it...............i don't care what the customer says or does. i'll box it all up and tell them to take it back to whomever installed it and ask for a refund. throw it back on them.

i have a shop camera i now use to snap shots of shoddy work. it really helps during the explanation of why, when, and how. i'll end with the raw fuel issue, check evap hose pouting........

[GEEPINCJ7]

FIXED! The problem ended up being that a shadetree mechanic reversed the return line to the tank and the vapor line when they replaced fuel pump. I had no idea the fuel pump was even changed. Once I found the problem I switched the lines, dropped the tank and replaced the canister. Now it runs great. Thanks all for the help.

[Jeff @ Able Auto]

Cool. Thanks for lettin us know.

[steven kiser]

a posted fix, next thing ya know the cub's are going to win the series........

[Rich]

Hey! thanks for posting the fix! It helps out the other folks. I'll keep this in my gray matter. Would be great to be the DUF and walk back and tell the techs what to look at first...and be right! For once they'd think I had a brain!

[fortknoxx]

Rich, I know how you feel. I was at a local shop where my piece's sisters car was. They were trying to figure out why it was bogging. I asked it it was bogging under load or idle. Under load was there answer. I said " what about the egr? Ding, ding,ding!

I too learn so much from this forum, almost makes me look like I might know what I am doing!