Is there any way to test electronic enjectors? there off a 88 efi 4.9. Fuel pressure sits at about 60psi when the truck is running but when you kill it the fuel pressure drops down to nothing with no fuel retuning to the tank. im thinking that i'v got a wasted injector. any thoughts???

 

maybe a bad fuel regulator

 

pull them, if you can blow thru them then they are stuck open LOL

 

Regulator is bad...not letting any fuel back to the tank....or maybe the vacuum line going to the regulator is broken.

 

if the pressure is dropping, gas is going 'somewhere'. If there are no leaks then its only got 4 exits - back to the tank via the feed line, back to the tank via return line, into the engine via leaking injectors, or into the engine via vacuum line on the fpr.

He seems sure its not going back into the tank so that leaves injectors or vacuum line. The vacuum line is easy to test. Injectors are not that bad either, I use a compressor to blow air thru them (set at 35psi) after I left them soak in seafoam overnight. I rigged a little 9v battery to a switch and injector harness and I can actually see them work. You'd be surprised at the crap you'll blow out of one.