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Fuel pressure question

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Posted by: jimbob

Hi Guys, i got a problem on my car ('92 Bill Blass) when it is first run from cold, the engine coughs occasionally at about 35mph, and if you accelerate too quickly from a standing start it will cut out. If it does cut out here, you have to floorboard the gas pedal hard to get it restarted.

Anyways, I had previously serviced the car, fuel filter included and have taken fuel pressure readings at the shrader valve as follows:

When the car is started and idleing it runs at about 35psi, if you suddenly open the throttle it shoots up to about 40psi (i think this is related to the cut out problem) before dropping back to 35 psi. If you open the throttle slowly it remains at 35 psi throughout.

Does this sound normal? If not any ideas what to check next?

Thanks

Posted by: JoshMcMadMac

The fuel pressure sounds ok. A good idea is to pull codes; that often helps narrow things down substantially.

Posted by: NYC LS8

Quote:

Originally Posted by jimbob

When the car is started and idleing it runs at about 35psi, if you suddenly open the throttle it shoots up to about 40psi (i think this is related to the cut out problem) before dropping back to 35 psi. If you open the throttle slowly it remains at 35 psi throughout.

Does this sound normal?

That's normal.

Posted by: OldSchool1

Pull codes.
My vote is vacuum leak.

Posted by: jimbob

Thanks guys, ill try and pull the codes off as you suggest. Oldschool1: Where would you suspect a vacum leak? The fuel pressure regulator?

Posted by: Sifrino3

Check for a plastic line by the rubber intake. Very easy to crack on of those.

Posted by: kimberlyrose

which hose?

Quote:

Originally Posted by Sifrino3

Check for a plastic line by the rubber intake. Very easy to crack on of those.

Posted by: WALT

Thats normal fuel pressure --the fuel pressure regulator is mounted in the fuel rail and tapped into the vacuum port -- It will sense acceleration ( loss of vacuum ) and accordingly increase fuel pressure to compensate for the acceleration schedule that the fuel injectors are operating under
Injectors controlled by the EEC ( Electronic Engine Control ) -- Fuel pressure mechanical --- Really sounds like you have something else going on here
and of course the computer is running that engine so it would be best to do as
previously suggested and use a scanner or code reader and see what the computer
is doing ---
let us know what you find --
Walt