1991 Suburban No-Start

[Thunderstruck20]

I realize this isnt exactly a GMT 400 platform but over memorial day weekend I trailered my burban to the mud bog. First day i had a little fun before she killed on me. Cranks great but theres no fuel coming from the injectors. Loaded her on the trailer with starting fluid so I know theres spark. Im getting fuel to the TB but im not getting an electrical current to my injectors. been working on and off the past week and over that time Ive replaced the fuel pump and filter just to be safe and ive tested the wiring from the pcm to the injectors and grounds, which all tested ok, and both ECM fuses are ok. Is there anything blatantly obvious that im missing? Any input that might help me solve this problem is greatly appreciated. Thanks

 

[Mean Green]

Have you tested for current @ the connector on either of the injectors?

 

[Thunderstruck20]

yes I have, they arent getting any current but the wiring from the pcm to the connector has no resistance so could it be a fault in the pcm?

 

[Yeti_Owner]

yes I have, they arent getting any current but the wiring from the pcm to the connector has no resistance so could it be a fault in the pcm?

That's pretty much an impossibility. It will always have a measurable resistance, unless it's open and reading infinite (or unless the multimeter is not very sensitive). Switch your multimeter over to continuity, unplug the injectors and PCM, and test the wires that way. If you have continuity but no current, the PCM went "poof".

 

[Thunderstruck20]

i have no voltage reading key on at the injectors (measured from both pins on each inj just to be safe), fuses are all good, it wouldnt be a bad evrv or egr solenoid would it? Correct me if im wrong but its my understanding that theyre part of the same circuit only they run in parallel so even if one was bad i should still be getting voltage to the injectors?

 

[Yeti_Owner]

You won't. They pulse when the motor is cranking. You need a noid light plugged in to the connector, and it will blink while cranking. 2 bucks at Autozone/etc.

 

[Thunderstruck20]

You won't. They pulse when the motor is cranking. You need a noid light plugged in to the connector, and it will blink while cranking. 2 bucks at Autozone/etc.

wow... i feel like a dumbass haha yeah theyd only pulse when it was getting voltage which would only be when cranking, cant believe i didnt realize that

 

[great white]

So, back to square one: does the ECM have any stored trouble codes?

 

[Thunderstruck20]

i dont know. when i plug my scan tool in i get "no data at ALDL." i know that the CEL would come on intermittently but i never had a problem with the truck until now

 

[great white]

you don't need a scan tool for GM OBDI.

Ground the diagnostic pin in the ALDL connector and it will enter diagnostic mode and flash the CEL to tell you the codes:

http://www.454ss.com/cgi-bin/forum/YaBB.pl?num=1276459916

I find most over the counter code readers are dodgey at best. The OBDI readers are just a ploy to get your money as a simple paper clip does the same job, most times it does it better. The ones that can run module tests are a bit better than the simple "here's your trouble code" jobbies.

If the CEL was flashing while you were driving, there should be history codes in there that can lead you down the right diagnostic tree. Active codes send you down another.

No codes leads to items the ECM doesn't watch at all.

Check it out....