fuel pump failing?
 

94 1.8L with a turbo, begi rising rate. when i jump the fuel pump so it comes on with ignition, static pressure is fine, but when i clamp the return line, i only get 68psi... is my fuel pump dying? its not stock, its similar to a walbro 190. any suggestions?

Here's what I have in the workshop manual:

Jumper F/P And GND
Turn ignition switch on
Measure the max pressure:

Fuel Pump max pressure (70 to 90 PSI)

That doesn't mention having the return line clamped. It's possible though that your stock FPR is going....

Or it could be your fuel pump... however, when I had my stock fuel pump go... I was returning from the track, and basically, under constant load, the AF gauge would go full lean, and the car would stumble. Once the pump kicked back in again, it was fine. I go home, and swapped the pump for a 255 I had, and it's been find ever since. (minus having the stock FPR go....)

One way to check your stock FPR is to jumper the FP/gnd, and get pressure in the line. You should see > 21psi in the rail after 5mins....

Dave,

stock pump with the return clamped should be around 70-80psi.

If its pushing 68 PSI and its supposed to be similar to a walbro 190, you've got an issue. The walbro 190 should easily push higher than that. Its been at least a year since I hooked mine to a gauge, so maybe someone who measured their walbro recently can tell you the exact range.

ah, ok. thanks for the replies. should i measure volume? i think something like disconnect the return line, put it in a bucket, jumper the fuel pump and see what comes out. like 1 pint in ten seconds?

ok, just did some checks with the car running. idle is 38psi. with vacuum line disconnected from stock fpr i get 45 psi. with return line clamped i get 99psi. and after i shut the car off, pressure stays at 35 psi for more than five mintues.. so i guess its a tuning issue...

yeah that's about what you should be getting with an aftermarket punmp

ok. good. thanks