james125 Posted February 21, 2012 Report Share Posted February 21, 2012 Hello guys new to the forum and starting to have some issues with my 1995 Grand prix DOHC 3.4L. Ok so I bought this car for commuting back and forth to work car is spotless very clean with 150k on it but its been a problem since i bought it. So when I drive it it runs ok I can drive it for hours but if i let it idle for more than 2-3 minnuts the thing will start to run rough spit n sputter and then die, and when it dies it will not start intill it cools down at least 1 hour and then it will run fine. I checked the shrader valve on the fuel rail and nothing but air comes out after it dies even while cranking only air will come out, So could it be a fuel pump i changed the fuel filter but that did not help and its not overheating? any ideas would be great thanks. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted February 21, 2012 Report Share Posted February 21, 2012 got any way to check the actual fuel pressure when something like this happens? almost sounds like an extreme case of vapor locking, which may or may not be caused by the fuel pressure regulator. Quote Link to comment Share on other sites More sharing options...
james125 Posted February 23, 2012 Author Report Share Posted February 23, 2012 ok I will check it tomorrow, What should the PSI be at? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted February 23, 2012 Report Share Posted February 23, 2012 key on, engine off, around 43.5PSI. key on, engine running with the FPR connected to vacuum, near idle, about 3-10PSI lower key on, engine running with the FPR disconnected from vacuum, 43.5PSI. just expect that last one to cause the engine to run a bit rich. Quote Link to comment Share on other sites More sharing options...
james125 Posted February 24, 2012 Author Report Share Posted February 24, 2012 Yea just checked it 18-22 psi, looks like i will be changing the fuel pump how hard is it to drop the tank any tips? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted February 24, 2012 Report Share Posted February 24, 2012 low pressure can also be caused by the FPR being bad. and changing the fuel pump does require dropping the tank, or cutting a hole in your trunk. you only need to remove two of the bolts for the tank straps, but i forget which two. Quote Link to comment Share on other sites More sharing options...
Addicted To Boost Posted February 24, 2012 Report Share Posted February 24, 2012 You only need to remove the front two strap bolts. Don't bother to remove the rears, you don't need to. Quote Link to comment Share on other sites More sharing options...
james125 Posted February 24, 2012 Author Report Share Posted February 24, 2012 Where is the FPR located? Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted February 24, 2012 Report Share Posted February 24, 2012 on the fuel rail Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted February 24, 2012 Report Share Posted February 24, 2012 IIRC on a LQ1 you need to pull the upper intake to get at it. Quote Link to comment Share on other sites More sharing options...
GOT2B GM Posted February 24, 2012 Report Share Posted February 24, 2012 yeah the 'saar is correct Quote Link to comment Share on other sites More sharing options...
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