91 305 tpi. At start I have fuel pressure priming at under 40. It then drops to around me 10. When I can get it running pressure is mid 30. I adjusted the afpr both ways with no change. Now i can't get it started. It will crank and run with started fluid but dies. New fuel filter installed and gas in the tank. I do hear the pump prime. Pump is a few years old and a parts store pump
Any ideas?

 

Pinch the return line and prime the pump. What does it read?

 

ill try it tomorrow when im home. what should i be watching for?

 

With the return line pinched it should prime above 40 psi. Mine would go up to around 60 psi with the return pinched while the pump was running. Note that if your check valve in the fuel pump isn't working it will drop back down pretty fast, so hopefully you have the gauge somewhere you can see it while priming if that's the case.

 

i have a gauge on the rail. if it doesnt prime that high, is that a bad pump? or sending unit

 

The pump feeds the sending unit via a hose or what's called a pulsator. Whatever is there on yours could be a problem. The pump could also be the problem. The other possibilities are injectors leaking or pressure regulator. I've ran into bad pulsators more than once. If the pressure builds higher than before and suddenly drops after the pump primes I'd be looking in the tank for a problem. If a spark plug is wet, it's an injector. If the vacuum line on the regulator has fuel in it, it's the regulator. Just gotta start searching.

 

the vacuums line and plugs are dry. I can hear the pump prime every time and it sound the same. Pressure when i can get it started is mid thirty.

 

Sounds like it's time for a new pump in the tank.

 

Don't run ethanol fuel in this car. Not any percentage of it.

 

today it started right up and acted normal. pressure at start and running still remained the same. im thinking its still a pump issue.