: cold start/warm start



The Director
07-14-04, 11:41 PM
Just recently I noticed that when I cold start my 93 STS it starts perfectly fine, BUT when I warm start it- it cranks for a long time before it starts. Sometimes during long cranks it'll backfire. BTW- I got new plugs, wires, etc.

Any thoughts?

BeelzeBob
07-14-04, 11:55 PM
You need to check the fuel pressure regulator for internal leakage that is allowing fuel to migrate to the intake manifold via the vacuum line causing an overrich condition on a hot start. On a cold start the extra fuel is not noticeable due to the extra fuel being added anyway due to the cold engine condition. On a hot restart, however, it makes it too rich for an immediate start.

On a 93/94 Northstar you will need to remove the intake top cover to check the fuel pressure regulator.

On a 95 and later you can see the fuel pressure regulator when the silver beauty cover is removed. Remove the vacuum line to the FPR while the engine is idling and watch the vacuum nipple for any sign of fuel...there should be none.

apletts
07-15-04, 12:40 AM
Hi..had same problem and replaced the pressure valve..no more starting problems....apletts..

The Director
07-15-04, 03:23 AM
Thanks guys for the replies. Will check those things ASASP.

BeelzeBob
07-15-04, 12:06 PM
I think those "those things" are the same thing. There is no "pressure valve" per se...just the fuel pressure regulator.

OlManRivah
07-15-04, 12:52 PM
My '97 started taking 3 or 4 revs to start when warm. Not bad, but a little annoying. Since I had a bumper to bumper warrenty, I took it to the Dealer last week and suggested the FPR. They replaced it and she's running like it should.

It has 82K on it and I think leaking FPR's are not uncommon with the Northstar. If you don't mind the extra rev's, it'll probably run for quite awhile like that. Although, it's better to take care of stuff as it happens.