We have a 97 Diamante LS with 3.5L V6. Engine does not want to start on hot soak condition. Checked fuel pressure and is fine when car is cranking normally. However when condition exists, fuel pressure will vary rapidly from 20 psi up to 60 psi. When cracking fuel lines during condition, appears to be alot of vapor ejecting from fuel lines. Have tried starting fluid during condition, still no-start. Have checked spark, spark seems fine on all cylinders. Problem started after mechanic removed upper plenum to replace spark plugs.
diamante LS hot soak No-Start
Sep 09, 2006
2 Replies
Sounds to me like something was not put back properly eg improperly seated or sealed, or damaged and not noticed. Fuel pressure should not vary so much, and there's a pressure regulator that returns the low pressure fuel to the tank. This regulator may or may not have a control solenoid from the ECU / emissions system. If a vacuum hose is cracked you could get the effect you describe.
I wonder if the setup is like the early Northstars with the FPR inside the plenum and deriving vacuum from it.
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