i have been dealing with a real bad missing/stumbling problem for awhile now and today i checked the resistance on the inj. they were all 16.2 ohms which i beleive is ok. heres the prob, as soon as i cut the car off the fuel pressure drops to zero IMMEDIATELY, even when i pinch off the return. im am guessing this means that one or more of the injectors is hung wide open. fuel pressure is 38 with vacuum on and 45 with it off. would a wide open inj. cause a real bad idle and bucking and sometimes stalling prob? its seems like it is running super rich. i am at whits end with this tpi. are there any other test i can do to make positivley sure that i need to replace the inj? at low speed sometimes it bucks and runs crappy and sometimes it doesnt. when i am out on the road it seems to run pretty well, that is why i am stumped. any help is appreciated. i was dead set on a carb and my buddy talked me out of it, but this tpi is just so nerve wrecking. thanks in advance!!!

 

Bubbz,

You've done all the homework. Unless the fuel pressure regulator is leaking through to the vacuum line, you likely have an injector stuck open or leaking through. You may have more than one. Instead of new replacements, you might want to talk to Rich at www.cruzinperformance.com about clenaing and flowing yours.

 

they were sent to him 24k miles ago. i am prob just gonna get new ones. can you reccomend some? thanks man

 

Before you get excited about pulling the injectors, make sure they are not static (always open). This can be caused by grounding in the injector wiring harness.

 

how exactly do i test them?

 

 

anyone know how to check the harness???

 

$5 injector test light at Pep Boys. If it is on w/ the key off, you're static. If it goes solid on while cranking, you're static.

If it's off with the key off, and flashes while cranking, you're good.

 

one of those noid lights?

 

Uh, yeah. The package says something like "Injector Test Light" so go grab the one for GM multi-port injection.

 

thanks man i really appreciate it