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Ivan, ASE Certified Master Technician
Category: Chevy
Satisfied Customers: 4871
Experience:  ASE Master Tech. 20+ years experience. 9 years self employed. Expert on AUTOLAB Radio Show
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2002 chevy impala 3.8 mpfi , car starts and runs but if you

Customer Question

2002 chevy impala 3.8 mpfi , car starts and runs but if you turn it off after running it for 10 or so minutes,and come back and try to start , ,it it starts and dies continually, if it sets for ahalf an hour minimum at least then it will start back up , please give me some assistance in figuring this one out thanks duane

Optional Information:
Year : 2002
Make : Chevrolet
Model : impala ls
Engine : 3.8

Already Tried:
replaced the fuel filter. cked fuel pressure reads about 43 psi, thought might have been the ign module under coil packs were maybe breking down when getting hot so i replaced ign module and have the same issue. do you think maybe it could be either the crank or cam sensors? from what i remember if the cranks sensor goes out car stops having spark but what if it the cam sensor ? also replaced the irediam spark plugs. any assitance in this would be greatly apprecated. REMEMBER AFTER IT COOLS BACK DOWN IT WILL START BACK UP AND RUN AND REV UP AND IDLE SMOOTH AS GLASS. thanks duane
thanks duane
Submitted: 6 years ago.
Category: Chevy
Expert:  Dan replied 6 years ago.

Fuel pressure is low. Verify pressure is higher when vehicle will start and run and lower when it wont stay running. Then replace filter and check again, if still low replace pump. It takes more pressure to start it then keep it running, let me know if you have questions. Thanks.


Fuel Pressure
Pressure 1 (PSI)Pressure 2 (PSI)Pressure 3 (PSI)
53.0 - 59.0Y40143.0 - 56.0Y40259.0Y403
Y401: System pressure with ignition on & engine off (PSI).
Y402: System pressure while idling (PSI).
Y403: Fuel pump pressure (PSI) with return line briefly restricted.

Customer: replied 6 years ago.
Dan thanks for the reply according to mitchell on demand it said specs were 35- 38 and it doesnt seem to drop when vehicle starts and dies, thats what the specs are at when vehicle starts, explain to me please the relationship with the cam. crank, and controller module, you dont think its anything in the electrical system. causing it to have maybe a weak spark after it has been running and warmed up?? my original assumption was the fuel pump but when i cked fuel pressure and it didnt seem to decrease that much i decided it must be spark or ign system related instead. please let me know what other ideas and what should i have according to specs on fuel pressure. i dont have a obd2 scanner so all i have is to cycle the key and of coarse running and cking fuel pressure so whats your thoughts?? hope to hear back from u soon duane
Expert:  Dan replied 6 years ago.
Ok, mitchel is wrong..fuel pressure needs to be at lesat 53 psi. I have 3 different sources that all say 53psi. So check fuel pressure when it starts and runs and compare it to when it wont run and if its lower replace the pump. If it was the spark or ignition system it would stall......but with a low fuel pressure problem it can run until its shut off since it takes more pressure to start it. Let me know if you have questions, thanks.
Customer: replied 6 years ago.
Thanks i will ck when i get back home this afternoon and i will email u back if i have further questions .
Expert:  Dan replied 6 years ago.
Sounds good, let me know. Thanks.
Customer: replied 6 years ago.
ok dan so heres whats happening now it started right up and showed 43 psi let it run pulled thr reg vauum line and pressure jumped to 53 psi, after letting it run for 15 or so minutes we turned it off and let it heat soak for adout 15 minutes, when trying to restart it starts and stalls when it fires up fuel pressure is showing very close to 50psi for the 2 seconds it runs then stalls and fuel pressure only drops to 43psi. it acts like someone is turning off the key on the ignition so,,,,,,,,,,,now what? please dont abandaned me on this one i really need you help thanks duane
Expert:  Dan replied 6 years ago.

Is the security/theft light on or flashing? Try to pull a spark plug and monitor spark when this happens.

Customer: replied 6 years ago.
ok now no security light on or flashing that ive noticed and spark seems to be kind of weak this is why i was wondering about the crank and or cam sensors. i would expect to see a bright blue spark but its more orange instead, hince the changing of the ignition module.
Expert:  Dan replied 6 years ago.

Those sensors shouldnt cause the spark to be weak......Try to compare the way the spark looks from when it runs good to when it doesnt. Also use alternative fuel such as starting fluid to try and keep it running....If that helps then we know its a fuel related problem.

Customer: replied 6 years ago.
parts store is closed i will try that tommarow afternoon and email back now im just checking this is all under 1 question im not getting change d for each email am i?
Expert:  Dan replied 6 years ago.
No you only get charged when you click accept.
Customer: replied 6 years ago.
cool thanks so i ,,will try the ideas and email back tommarow i appreciate your assistance i will email tommarow and we will see what happens
Expert:  Dan replied 6 years ago.
Sounds good, I'll talk to you then.
Customer: replied 6 years ago.
Ok dan so i changed the spark plugs and then let car run at around 1500 rpm till it was warmed up , turned it off let it heat soak for about 15 minutes, the when restarting it now will start and run as long as you have it reved up to about 1500 rpm and if you let it go below that it just stalls and chokes, the spark doesnt change between before and after and adding carb spray to the intake doesnt help you just hear it choke out in the plenium and aircleaner assy , fuel pressure stays at 43 psi so what do you think now?
Expert:  Dan replied 6 years ago.

I'm really not sure.....I'll opt-out of this question and leave it open to other experts. Someone will reply automatically so dont reply otherwise question gets locked to me. thanks.



Expert:  Ivan replied 6 years ago.

HelloCustomer I see you've been working with Dan. I have one thing to try. It happened to me twice with 3800 Impalas so it's worth a shot. Disconnect the Canister Purge solenoid and see if the problem goes away. It's mounted toward the front valve cover. Let me know if it makes any difference.


Your JA Expert,


Customer: replied 6 years ago.
Ivan what was the synptom of the 3800 impala you worked on?
Expert:  Ivan replied 6 years ago.
A no start or very hard start at times. It was when the engine was warm, I believe. The canister purge solenoid would short, pulling the computer down with it. That happened twice, 2 different cars, both 3800s.
Customer: replied 6 years ago.
Ivan are we talking about the solonid thats attached to all the vauum lines in front of the valave cover ? because i went to the dealership and they gave me the solonid and its not the same , i did however did unplug the soloid that is mounted with the vacuum lines and it still stalls and wont idle, my buddy at the dealership said the purge solonid is located in the rear of the car above the gas tank and i dont see a solonid plug so what now let me know thanks duane
Expert:  Ivan replied 6 years ago.

Duane, here is it's location.



Customer: replied 6 years ago.

are you going to adandan me already , your a master tech , i have a driability problem,plea

se or kindly open the question back up as dan did respectfully duane . retired master tech my specialty was drivability but i have been out of the drivability loop for a while now.somethings shuting down and not allowing it not to idle. after it warms up ,

Expert:  Ivan replied 6 years ago.
No, I'm not abandoning you, I sent you a picture just before of the canister purge control solenoid's location. Did you see it?
Customer: replied 6 years ago.
Relist: Incomplete answer.
i have a drvability problem with my car im asking for some help not just give a suggestion. i need a ase performance (drivibility expert) what is a c11 and a c126 in the diagram anyways
Customer: replied 6 years ago.
Relist: Incomplete answer.
i need a ase certified in engine performance and drivavbility specialist. i know somebody has come across this before

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