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Ask Dave Nova Your Own Question
Dave Nova
Dave Nova, Buick Technician
Category: Buick
Satisfied Customers: 19450
Experience:  ASE Master Certification. GM World Class Certification
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Bought a used 2001 buick lesabre off of Craigslist. It ran

Customer Question

Bought a used 2001 buick lesabre off of Craigslist. It ran perfect. I pulled the fuel pump relay to relieve fuel pressure, then I changed the fuel filter. Put FP relay back in. I started it up and ran it around the block to test it. The next morning it cranks and even turns over but dies immediately. If I give stay on the throttle it will stay running, but it dies as soon as I let off.
JA: Sometimes things that you think will be really complicated end up being easy to fix with a Buick. The Buick Mechanic I'm going to connect you with knows all the tricks and shortcuts. Are you hoping to fix this yourself?
Customer: I am hoping to
JA: Is there anything else the Buick Mechanic should be aware of about your Buick?
Customer: 104k miles. Been in LV or AZ its whole life. I've already done a lot of testing, its gonna be a novel
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Buick Mechanic about your situation and then connect you two.
Submitted: 7 months ago.
Category: Buick
Expert:  Amedee replied 7 months ago.
Hello and welcome! My name is ***** ***** I can assist you with your question. Have you checked the fuel pressure regulator to see if it is leaking? It might be leaking fuel into the vacuum hose or line causing this stalling condition..
Customer: replied 7 months ago.
The fuel pressure regulator was not leaking but I replaced it anyway. Here is what I can tell you:
There are no codes
The fuel pump was noisy and the rear smelled of fuel when it did run, so I replaced that. I can hear it prime and the fuel pressure is 51 so it tests good.
It has strong spark on all coils/plugs. I replaced the plugs anyway because I didn't know if they had ever been replaced. The old plugs were black/sooty so I know it's rich.
There are no vacuum leaks detected.
Expert:  Amedee replied 7 months ago.
Thank you for that information. Does the fuel pressure leak down with the key on engine off or when turning the key off?
Customer: replied 7 months ago.
After a second prime the pressure pegged at 51 quickly and stayed there until turning the power off. I don't recall what the gauge did once power was off.
Expert:  Amedee replied 7 months ago.
Is there anyway you can check this for me?
Customer: replied 7 months ago.
Sorry disregard the phone request. I can check in a few hours when I am home
Expert:  Amedee replied 7 months ago.
Sounds good.
Customer: replied 7 months ago.
OK so I did a fuel pressure test again. It went up to maybe 58 for a second or two, then dropped to 50 and stayed. When the power is turned off it stays at 50 and isn't creeping down at all.
Customer: replied 7 months ago.
OK I stand corrected, it's creeping down ever so slightly, it's down to 49 after maybe 4 mins and dropping
Expert:  Amedee replied 7 months ago.
Does it continue dropping down lower than 45 psi, 40 or even as low as 35 psi?
Customer: replied 7 months ago.
It's been almost 10 mins and it stopped at 48
Expert:  Amedee replied 7 months ago.
Ok, good, then that should not be an issue..
Customer: replied 7 months ago.
The only other thing I can think to tell you is I had a "mobile mechanic" look at it and he said it wouldn't let him read the live data so maybe the PCM was bad but apparently that is a rare occurrence
Expert:  Amedee replied 7 months ago.
That is a possibility. Does the TPS have a 5 volt reference going to it with the key on?
Customer: replied 7 months ago.
I have a multimeter though I still don't know how to check volts with it... I can if you walk me through it
Customer: replied 7 months ago.
Oh and I left the fuel pressure gauge on and after like 75 mins it was at 41, not sure if that is negligible or significant
Expert:  Amedee replied 7 months ago.
That is ok. YES, I can walk you through this over the phone..
Customer: replied 7 months ago.
I'm gonna try to figure it out real quick I'll keep you posted
Expert:  Dave Nova replied 7 months ago.
New expert here. Try unplugging the mass airflow sensor, then start the engine. Does it stay running?
Customer: replied 7 months ago.
@ Dave that had been tried previously, no it doesn't stay running
Expert:  Dave Nova replied 7 months ago.
Is the check engine light on with the engine running?
Customer: replied 7 months ago.
No check engine light, no codes
Expert:  Dave Nova replied 7 months ago.
Has the throttle body been cleaned?
Customer: replied 7 months ago.
Not that I know of, I can do that
Expert:  Dave Nova replied 7 months ago.
Do that and let me know how it turns out. It could be excessive carbon buildup that is not allowing the engine to run at idle speeds.
Customer: replied 7 months ago.
I keep getting an email notification about every half an hour to reply to the message from Amedee saying "yes that is OK. I can walk you through it over the phone" can you make that stop please? Thank you
Expert:  Dave Nova replied 7 months ago.
As an expert I cannot access that part of the site. Look for a help link at the top or bottom of your page. There may be a way to report this problem there. There may also be a link in the email where you can decline his offer of a phone call. I am sorry I can't help with that.
Customer: replied 7 months ago.
Oh OK thank you
Expert:  Dave Nova replied 7 months ago.
Let me know how the throttle body cleaning goes and we can work on the problem from there.Dave
Customer: replied 7 months ago.
Will do Dave, I'll knock that out when I get home this evening
Expert:  Dave Nova replied 7 months ago.
Sounds great. Talk to you then.
Customer: replied 7 months ago.
Throttle body all clean and it started up! You can consider the issue resolved, thank you Dave!
Expert:  Dave Nova replied 7 months ago.
You are very welcome. Glad I could help.Dave