[RESOLVED] should the fpr open when trying to start the car?

[akira235]

my car won't start, and i'm thinking it is my fuel pump but i'm not sure. the car will fire once or twice if you hold down the mpi relay for a few seconds before trying to crank, but thats it. now my question is this:

while trying to crank the car, shouldn't fuel come out of the return line? especially if i have no fuel pressure solenoid, thus causing the regulator to not have increased pressure at start?

i read somewhere that you can check to see if you have fuel by "Simply pulling off the return line from the fpr and putting it in a bottle, if it comes out, you have fuel" but what if i have fuel to the rail, and it isn't getting past the regulator? doesn't that make fuel pressure to low, and therefor a bad fuel pump?

I CAN'T afford to get a gauge/tester right now.

 

[Burnett03]

The FPR opens when it reaches a certain pressure, whatever you have it set at, so if the pump is outputting the pressure of what the base is set at it should open and bypass fuel. It would be easier to turn the pump on 100% and see if fuel comes out. Or i would just remove the regulator, or just loosen it a bit and crank and see if fuel comes out.

 

[akira235]

its a stock regulator/pump. how do i turn the pressure to 100%

 

[rush2252]

its a stock regulator/pump. how do i turn the pressure to 100%

The MPI only activates initially to Prime the pump and send pressure to the rail. The pump then shuts off and doesnt reactivate until the car is running. If the car starts and then dies I would say the pump is bad. Another way to jump the pump instead of doing the MPI trick is use the connector under the hood. Search the post by "badabing33a" post 39 shows a good pic and also references same symptoms w all of the specs on fuel pressure etc.


EDIT** When you are jumping the MPI relay are you unplugging it and applying 12V to the pin or how are you jumping it? If you can hear the pump running while you do this then the MPI might be the problem not the pump.... Either way if the pump isnt coming on with the key switch but its functioning when bypassing the relay then the relay is the culprit. If the pump isnt running the ENTIRE time you are bypassing the relay then the pump is the problem.