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my 2001 3.8 liter grand prix gt has problems starting when ...

Sent to Car Experts March 12, 2007 9:42 p.m.

my 2001 3.8 liter grand prix gt has problems starting when the engine is warm. When cold, it starts right up but as soon as you run it and then let it sit for 10 minutes, it takes a couple cranks to get it to catch. Usually it will rev up and die the first or second time you try to start it.

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2001 Pontiac grand prix gt 3.8

Already Tried:
nothing

Customer (name blocked for privacy)

Status: Closed Value: $9

Answer
March 12, 2007 10:01 p.m. (18 minutes and 25 seconds later)

REPLIED

Hello,

Check the fuel pressure regulator on the fuel rail. It has a vacuum line going to it. When vehicle is warm, check the regulator by removing the vacuum line and see if fuel spits out when the key is turned on. If so, replace it. If not, make sure idle air control motor opens with key on located on throttle body. If not, you either have a defective IAC or or PCM. Also verify fuel pressure to see if it is present when it doesn't want to start. Here are the locations of the regulator and IAC. Hope this info helps. Just to let you know, Fuel pressure regulator is common.

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Brian9 -- Automotive Technician -- 100% Positive Feedback on 269 Car Accepts
14 years automotive experience, ASE certified, Expert Technician in driveability.

Reply to Brian9
Sent March 14, 2007 9:14 p.m. (1 day and 23 hours later)

i checked the fuel pressure regulator and it does not spit out gas when key is on. I checked the IAC with the key on and it was making twitching sounds. I removed it and it screws the plunger outward when the key is turned on. As for the fuel pressure, I've noticed there is usually fuel pressure at the back of the fuel rail and at the check valve on the fuel pressure regulator but not at the fuel line that comes into the regulator unless the key is on. The exception is when the engine is cold (when it always starts fine, then there is no pressure at the fuel regulator check valve.

Customer (name blocked for privacy)

Answer
March 14, 2007 9:42 p.m. (28 minutes and 28 seconds later)

REPLIED

It sounds like the fuel pressure is there. Check the Mass Air Flow sensor in the picture below for dirt on the 2 tiny wires after removing. If dirty, clean with electronics cleaner and clean the throttle plate if it appears dirty. Let me know how these look.

Brian9 -- Automotive Technician -- 100% Positive Feedback on 269 Car Accepts
14 years automotive experience, ASE certified, Expert Technician in driveability.

Answer
March 14, 2007 10:08 p.m. (26 minutes and 26 seconds later)

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Brian9 -- Automotive Technician -- 100% Positive Feedback on 269 Car Accepts
14 years automotive experience, ASE certified, Expert Technician in driveability.

Reply to Brian9
Sent March 15, 2007 6:09 p.m. (20 hours and 0 minutes later)

the two wires on the MAF looked fine. I also rechecked the fuel pressure regulator. This time I took the vacuum line off, with the key off, and when I sucked on it, I got a few drops of gasoline. Is that supposed to happen?

Customer (name blocked for privacy)

Answer
March 15, 2007 6:35 p.m. (25 minutes and 40 seconds later)

ACCEPTED

No, that is your problem. Get the part from GM. It is updated. Common problem. The fuel pressure regulator leaking fuel in the vacuum line is exactly what I wanted you to check. Sometimes it can be tricky to catch, but what happens is when you shut the car off warm, that fuel goes into the intake and when you start it warm, it over fuels the cylinders and gives the no start and high idle surge stall. This is a diagram of the regulator to help with replacement. Good job finding the problem. Just remember the small O ring all the way inside the hole the regulator goes.

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Brian9 -- Automotive Technician -- 100% Positive Feedback on 269 Car Accepts
14 years automotive experience, ASE certified, Expert Technician in driveability.

Reply
Sent March 15, 2007 6:59 p.m. (23 minutes and 55 seconds later)

alright, i'll replace it and let you know.

Customer (name blocked for privacy)

Reply to Brian9
Sent March 22, 2007 7:39 p.m. (7 days and 0 hours later)

I replaced the fuel pressure regulator and it works now. thanks for the advice.

Customer (name blocked for privacy)

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