tbi no injector pulse 1989 k1500

[Erik the Awful]

Check the continuity of the wiring from the ground side of the injectors to the ECM.

Also, those wire splices are butt-ugly. Get some heat shrink butt connectors - and not the ones with solder inside. Put a double crimp on each end, do a tug test, and then shrink 'em. The only times I've had bad connections, it was because the wire wasn't good.

 

[Schurkey]

Engine has spark, therefore the distributor pickup coil is good. I don't think it can be an ignition module problem, either. ECM or wire-harness seems most likely if there's power to the injectors but no grounding to make them squirt.

Been thinking about this. IF the ignition module were damaged in an uncommon way, you could have spark at cranking speed (< 400 RPM) but have no fuel spray.

Connect a scan tool, look for RPM signal when cranking. If you have RPM signal, it's not the module or wire carrying the RPM signal from module to ECM. If you DON'T have an RPM signal when cranking, the module and that wire are suspect, and the likely cause of no fuel spray.

 

[Mathies]

Really appreciate all the help

But when the truck is running faster then 400rpms the ecm should take the injector spray over right? Bcs when i let it for like 20 sec on start pilot the injectors still wouldnt spray.

And ill take it to a mechanic so he can use a scope and see if there is rpm signal or other stuff that isnt going trough correctly. Or could i buy a scan tool myself?

 

[Schurkey]

when the truck is running faster then 400rpms the ecm should take the injector spray over right? Bcs when i let it for like 20 sec on start pilot the injectors still wouldnt spray.

The ignition module handles SPARK when the engine RPM is below 400.

The computer handles injector firing ALL the time.

And ill take it to a mechanic so he can use a scope and see if there is rpm signal or other stuff that isnt going trough correctly. Or could i buy a scan tool myself?

Up to you. "I" want a scan tool, because I'm perpetually screwing with computer-controlled vehicles, either my own or those of friends/family. I've gotten my scan tools "used" from eBay, at a substantial discount from "new" prices.

But if you're not planning to do much work on computer-controlled vehicles, paying someone else to be "the expert" is not a bad plan--depending on how much they charge you. I can imagine two or three trips to The Expert would cost as much as buying your own scan tool (but then you have to learn how to use it!)

 

[Bnixon]

I had an issue with no pulse to the injectors and it turned out to be a bad ignition module. computer won't fire injectors without the proper reading from the ignition module.

 

[Another]

Had the problem as well, forgot to connect that little wire at the starter when I put a new one in, so trace it and make sure it is unbroken.