Fuel pressure re-visited

[JWC]

Ok I need help. I tested my fuel pressure today and here is what I found out.

Hooked up pressure gauge turned key to on position the fuel pump ran and gauge read 43 psi, as soon as the pump shut off it went to 0, I then started the car the gauge read a steady 32 psi, the gave it some gas it shot up to 40 psi, when I turned the car off the gauge went to 0. I already replaced the fuel sending unit, pump, screen and the fuel pressure reg. I also checked the line back to the tank and it looked ok. Any clue what I should check next? can it be leaking from around the injectors? The gauge goes to 0 really quick.

[padgett]

Probably just the regulator not closing all of the way. Does it start immediately or do you have to crank.

[2seater]

Do you have any fuel in the vacuum line to the regulator? Unlikely since your pressures look reasonable, but it doesn't hurt to check. A leaky injector, at least one that bad, would probably give you a rough idle. The only other place I could think of would be the connection between the pump and the steel line that exits the tank, where the pulsator is located inside the tank. I have heard of some GM installed injectors, Motec if I remember right, that leaked externally after a heavy dose of injector cleaner, but ours generally use Bosch injectors, and you would smell a leak like that, even if not readily visible. There isn't any easy way to isolate the regulator , except by disconnecting the return line and plugging the port from the regulator to see if the pressure drop continues. You would need to be careful as the pump is capable of very high pressures if it has no way to return fuel. An alternative, would be to disconnect the return and slowly bump the pressure up to around 40 psi and see if the return from the regulator allows fuel through. It shoudn't until it reaches the normal set pressure of around 43psi. This is also somewhat dangerous.

[JWC]

It cranks a lot before it will start.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> Do you have any fuel in the vacuum line to the regulator? </div></div>

After removing the pressure gauge I did notice it being wet from the fuel in the rail, also the car runs great once it's started.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> The only other place I could think of would be the connection between the pump and the steel line that exits the tank </div></div>

I had this hard starting problem before replacing the pump.