89 high pressure fuel pump bad?

[Krafty]

89 302 efi with low pressure in tank and high pressure in line pumps. Will not start

no fuel leaking, pressure regulator is good, can hear pump running.

there is lots of pressure when pump is running, but when it stops pressure immediately drops back to 0.

can a bad fuel pump be letting the pressure back feed through the pump when it stops?

 

[Krafty]

I had a look at the FPR and it seems to be in good condition. it isn't leaking and clamping the return line doesn't solve the pressure problem, so FPR is not it.

there is for sure fuel getting to the rails, its just not staying in the rails. and not going throught the return line.

so would it be the pump not keeping the fuel between it and the rails? or would it be the reservoir not keeping fuel between it the pump and the fuel rails?

 

[Krafty]

I got a different pump from the scrap yard with no change. I was going to do a test to see if the pressure stayed in the fuel rails if I clamped the high pressure line as soon as the pump was turning off. but I never got around to it.

now another question is for the 89 fuel system, is the high pressure pump supposed to be on all the time when the engine is turning over? or is it only once its running? or does it only run as required?

my uncle said if the pump is running and that is when I have pressure, it should start and continue to run if the pump keeps going.

and when its turning over the pump won't run, it will prime the system, then stop

 

[BroncoJoe19]

How have you determined that your FPR is good? It sounds bad to me.

 

[BroncoJoe19]

How have you determined that your FPR is good? It sounds bad to me.

 

[Krafty]

I pulled it off, checked the diaphragm with a vacuum test, checked the seals and reinstalled it.

AND cause weather or not I clamp the return line with a c clamp I still have 0 residual pressure after pump stops.

read the posts "I had a look at the FPR and it seems to be in good condition. it isn't leaking and clamping the return line doesn't solve the pressure problem, so FPR is not it."

Trust me if I say its good, I've done my homework . Its Good..

 

[Krafty]

I don't have all the know how on the electronics and it isn't so important now that it's not running. Today I'm starting to strip the body down and I'm gonna get the body fixed and painted then send it to my uncles shop for getting in running and e tested and certified

thanks for all the help anyways