95 cobra fuel pressure help!!

[flygilmore]

I have a 95 cobra...stock motor w/a V1 s-trim installed. Fuel pressure has always been(while at idle 39-40psi) but lately, it has dropped down to around 30-31 @ idle and doesn't seem to increase with throttle. This has happened slowly and I can't put a finger on when it happened. Also, the car when coming to a stop, when the clutch is pressed in, drops rpm's quickly like it is going to die and has several times. Other than this, it appears to be running normal-of course I haven't been pushing the car at all til this is figured out. It has the stock FPR, 255lph in tank etc. FMU, 24lb injectors recent fuel filter ( 2,000miles ago). I am not sure what is going on here. I need some opinions to try and find the source of the lower pressure and dying issue.

I searched the threads and it says 31-32 @idle vaccum on is good, but mine has always read 39-40 so I am basing on this. Thanks for your help!!!

 

[flygilmore]

Just went out and checked a couple of things. When I unplug the vaccum from the top of the FPR, the fuel pressure only goes up 1lb. to around 33lb. total. Also, when I turn the car off, the fuel pressure drops all of a sudden to around 24lb. I figured these things might help the diagnosis.

Thanks!

 

[Chythar]

You've done some good diagnosis on the issue. I believe that the fuel pumps don't fail that way, they usually just don't run. A bad fpr on the other hand, can give the symptoms you're describing. With the vacuum line off, the fuel pressure should be 38-40 at idle. 33 is certainly too low, so I would say your fpr is shot. Time for a new one.

 

[95Vert383AOD]

You've done some good diagnosis on the issue. I believe that the fuel pumps don't fail that way, they usually just don't run. A bad fpr on the other hand, can give the symptoms you're describing. With the vacuum line off, the fuel pressure should be 38-40 at idle. 33 is certainly too low, so I would say your fpr is shot. Time for a new one.

+1 and get one of them fangdangled adjustable ones

 

[inphiniti]

i just went with an aeromotive fuel pressure regulator, awesome so far

 

[Chythar]

+1 and get one of them fangdangled adjustable ones

Maybe, depends on his emission requirements in his state. In CA where I am, they're very illegal. Of course, no one noticed my bright red Aeromotive one for ages. Anyway, I disagree. An adjustable FPR is only a patch for a problem IMO. If you need to boost your fuel pressure, you really should get a proper tune. Flygilmore didn't mention any issues with running lean before the fuel pressure dropped, so I would simply recommend an OEM replacement.