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sundevil64 sundevil64 is offline
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Join Date: Apr 2009
Location: Cedar Park,TX
Posts: 2,617
Need Help with fuel pressure

I am trying to trouble shoot the car being overly rich with throttle imput and too lean while just idling. It will stall out idling when warm.

I put gauges on the CIS. My system pressure was saying 86psi. When I would do a cold test the needle would drop quickly to about 25psi then shoot right back up to 86 and hold.
When I plug the wur in there were no changes to the pressure.

At first I thought it was the wur. It wasn't the element inside, that would warm up and the resistance was in spec for the strip. I checked the screen, cleaned the wur and reinstalled. Still no difference.

I finally purchased a rebuilt wur (not adjustable) car is mostly stock albeit SC cams and a K27hf turbo. I ran the gauge test again. Exactly the same results.

Is it possible the fuel return line could be plugged? I blew air through the return line and I could hear it entering the gas tank. Could it be the poppet valve. Doesn't that regulate system pressure as far as what bleeds off to the return line?

I removed it and it is clear of any obstructions.

I don't want to take this to a shop, I would prefer to work through it and learn. Any help would be appreciated. I would like to take this car to MO for Porsche Polooza in October, but I need to have confidence I 'm not going to get stuck or worse, damage the motor.

Thank you,

John- I blame and thank the longhood boys of Austin
-84 911 Carrera w/ 930 t/p,efi'd,dizzy free,HFS turbo, 78 930 RoW no option sunroof coupe, 64 Corvette roadster, 71 911T, 73 911E, 67 Bronco survivor. 71 FJ40, 95 M3 (for sale)
"Illegitimi non carborundum"

Last edited by sundevil64; 09-12-2011 at 03:31 PM.. Reason: add text and pic
Old 09-12-2011, 02:36 PM
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