Starting Problem
Thread Starter
Instructor
Joined: Feb 2019
Posts: 161
Likes: 14
Starting Problem
I have a 2000 C5 Base M6. It will start sputter and then stall. No DIC codes. Battery voltage is good. Grounds have been cleaned. Ignition switch and fuel pump replaced last year. Please help.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
How are you reading the DTCs??? Have you checked all the vital engine parameters when it dies
FUEL PRESSURE?
SPARK?
MASSIVE VACUUM LEAK??
Check the PCV lines and connections and the brake booster vacuum line for proper connections and see if any of the rubber lines and fittings are rotted. The PCV tubing that runs behind the intake manifold are well known to rot/split and leak vacuum.
If you have a big vacuum leak, it will have those symptoms.
Bill
FUEL PRESSURE?
SPARK?
MASSIVE VACUUM LEAK??
Check the PCV lines and connections and the brake booster vacuum line for proper connections and see if any of the rubber lines and fittings are rotted. The PCV tubing that runs behind the intake manifold are well known to rot/split and leak vacuum.
If you have a big vacuum leak, it will have those symptoms.
Bill
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
Not uncommon for a 20 YO car to develop these issues
Most common faults are
1 Dirty or fouled MAF sensor--especially if you have an oiled cold air filter ( vlean the MAF with Brakeclean)
2 Your throttle body is DIRTY A C5 has no idle air control valve so at start up the throttle is cracked open If it has carbon built up around the blade It will have start up and idle issues again take it off and clean it with Brakeclean
3 Make sure your FRONT 02's are working properly 02's have a life span of only 10-12 years If they are lazy or fouled they will create start up--idle issues as well as pour fuel mileage
4 least likely check your fuel pressure It needs to be about 50 PSI with the key ON and NO START and must stay about there--A bad fuel pump check valve will let the fuel drain back into the tank and not allow it to hold steady pressure
Most common faults are
1 Dirty or fouled MAF sensor--especially if you have an oiled cold air filter ( vlean the MAF with Brakeclean)
2 Your throttle body is DIRTY A C5 has no idle air control valve so at start up the throttle is cracked open If it has carbon built up around the blade It will have start up and idle issues again take it off and clean it with Brakeclean
3 Make sure your FRONT 02's are working properly 02's have a life span of only 10-12 years If they are lazy or fouled they will create start up--idle issues as well as pour fuel mileage
4 least likely check your fuel pressure It needs to be about 50 PSI with the key ON and NO START and must stay about there--A bad fuel pump check valve will let the fuel drain back into the tank and not allow it to hold steady pressure
Thread Starter
Instructor
Joined: Feb 2019
Posts: 161
Likes: 14
I really did not describe the problem correctly. It is definitely a fuel delivery / pressure problem. Unable to move the car more than a few feet. Could the the theft system shut the fuel pump down ? If so is there any way to bypass it for troubleshooting purposes ?
Thanks Ned
Thanks Ned
Drifting
Joined: Mar 2015
Posts: 1,421
Likes: 302
From: CSRA, SC
I really did not describe the problem correctly. It is definitely a fuel delivery / pressure problem. Unable to move the car more than a few feet. Could the the theft system shut the fuel pump down ? If so is there any way to bypass it for troubleshooting purposes ?
Thanks Ned
Thanks Ned
The anti theft system won't let you start the engine if it thinks you're stealing the car.
Last edited by oharal; Sep 26, 2020 at 05:26 PM.
Thread Starter
Instructor
Joined: Feb 2019
Posts: 161
Likes: 14
What you describe does not in anyway indicate a "definite" fuel issue. Fuel could well be an issue but even more likely could be a giant vacuum leak or other issue. Check on what the previous posters have suggested and report back for next steps.
The anti theft system won't let you start the engine if it thinks you're stealing the car.
The anti theft system won't let you start the engine if it thinks you're stealing the car.
Drifting
Joined: Mar 2015
Posts: 1,421
Likes: 302
From: CSRA, SC
How can you not be sure? It literally says if it thinks you're stealing the car it won't let you start the car by not enabling the fuel pump relay. It sounds like based on your current, limited description that your able to start and idle the car but if you move it or load the engine at all it dies. Is that accurate?
Melting Slicks
Joined: Sep 2008
Posts: 3,132
Likes: 799
From: Espanola New Mexico
I am wondering where that write up came from, on the C5 if the BCM does not receive the correct voltage\current level from the ignition switch contacts that press against the keys resistor pellet the BCM will not provide a ground to the TDR, which is the relay that sends power to energize the starter. If you have a true VATS problem the car will not even crank over, of course the BCM will also not provide an enable to the PCM to turn on the fuel injectors. Most likely you have a problem with the fuel delivery system.
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Thread Starter
Instructor
Joined: Feb 2019
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How can you not be sure? It literally says if it thinks you're stealing the car it won't let you start the car by not enabling the fuel pump relay. It sounds like based on your current, limited description that your able to start and idle the car but if you move it or load the engine at all it dies. Is that accurate?
Drifting
Joined: Mar 2015
Posts: 1,421
Likes: 302
From: CSRA, SC
Why do you think the engine will start and idle at all if the antitheft system is active and not enabling the fuel pump? If it starts and idles, even with difficulty, the antitheft system is not active. Start your troubleshooting with the simplest to test and most likely culprits as suggested by previous posts.
Drifting
Joined: Mar 2015
Posts: 1,421
Likes: 302
From: CSRA, SC
8 PSI is definitely bad. Hard for us to troubleshoot without that info. Let us know if it gets better with the new filter regulator.
Thread Starter
Instructor
Joined: Feb 2019
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Thanks for the help.
Drifting
Joined: Mar 2015
Posts: 1,421
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From: CSRA, SC
As for injectors, I bet you're going to be just fine. I wouldn't bother pulling them unless you have issues.
Race Director
Joined: Oct 2004
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Whatever you do, DO NOT use brake cleaner on the MAF. I've seen some guys have problems doing this, and there are articles out there advising against this very thing. MAF cleaner isn't that expensive, and is chemically different than brake cleaner. They make it for a reason. I use brake cleaner for a lot of things, but this isnt one of them.