Cold start problem

jcarter · #1 (**permalink**) 11-10-2006, 08:01 AM

This is a bit OT, I have a 96 GMC Surburban(yes, my brother has a Cobra).
The Suburban wont start if it has been sitting for a few days or if the weather is cold.
New heavy duty battery, new alternator, new fuel pump and filters, new fuel distribution unit as one was leaking(or whateveryoucallit). Fuel pressure up where it should be.
But it takes at least 30 seconds for the engine to start, once it starts, it runs perfectly. Nothing else is wrong, no bad computer codes. 82000 miles
Have had 3 different garages working on it, and now its at a GMC dealership and they cannot diagnose the problem either.
Its obviously a fuel problem, but nobody seems to be able to fix it nor determine where the trouble lies. I even called GM in Detroit but they had no clue?
Any help would be really appreciated, and I know you all here are experts.
Thank you,
Jane

Michael P. Wole · #2 (**permalink**) 11-10-2006, 08:12 AM

only quick fix I see is to trade it on FORD..seriously...ck the fuel pressure when you are having the problem..ie: after sitting and cold out..loosing fuel pressure somewhere

jcarter · #3 (**permalink**) 11-10-2006, 08:50 AM

Hi Michael, My husband has a great F150, a 94. And one of our kids works for Toyota. Heavens I shouldnt use that word here!

Seriously, I think youve got the answer! Ive got it at the agency and the tech has checked it, and thinks the pressure is OK, but I think that you have it figured out. Perhaps there is a tiny leak somewhere and when its running, or recently been running, the fuel pump can deal with it, but when starting on a cold day, or after sitting for few days, the fuel could very well have drained way back to the tank and might take a long time for the poor pump to get it up to the engine. But those pumps are under the fuel level, so it would seem to me that it is always 'primed'. Not like a well point pump which has lost its prime.
Thank you!
Jane
edit/add
Is there a check valve in the fuel system, or in the fuel pump?
If there were a leak, I wonder if the computer would come up with a code on it, as the emissions might be a bit off with a leak.

trularin · #4 (**permalink**) 11-10-2006, 11:26 AM

Throttle body check ball for fuel system.

If the check ball goes bad, the fuel drains back to the fuel tank and you start as if the truck had run out of gas.

It's just a possibility.

jcarter · #5 (**permalink**) 11-10-2006, 11:55 AM

Thank you! We are looking at all of this, and I am sure we will find it soon!
Jane

jcarter · #6 (**permalink**) 11-14-2006, 12:21 PM

Final chapter in the cold-start problem story, the GMC agency could NOT find the problem. It still starts hard when the weather is cold or if its been not started for a few days.
So looks like we just have to use it daily, and use the Ford when the weather is cold. If we do ever find the solution to this, I will post it here, if it could help anyone else with a similar problem.
Jane