injectors not firing.. again

**91dime** · 02-23-2016

So if it does fire up with fuel added manually, where do I look next?

**EDZIP** · 02-23-2016

Originally Posted by 91dime

So if it does fire up with fuel added manually, where do I look next?

Then you know it's a fuel related problem since you have spark, compression, ignition etc.

That's why I keep extra ecms and throttle bodies on the shelf..it's a lot faster to just swap with a known good component.

Make sure you have "spark at the plugs" ..I know you replaced the ICM...but those GM trucks are known for burning up ignition control modules...I keep a few of them on hand for that reason. If you don't have spark and wind up replacing the ICM...remember the engine might be full of raw gasoline from trying to start it...with spark your muffler could go boom.

Autozone can test the ICM for free...but they need to run the test at least 3 times and make sure you use thermo lube under the ICM to transfer the heat or it will burn up.

**91dime** · 02-23-2016

I have another ICM that Hopefully works along with thermal compound I use to build computers. Is it the heat that kills them or other factors along with heat?

**EDZIP** · 02-23-2016

Originally Posted by 91dime

I have another ICM that Hopefully works along with thermal compound I use to build computers. Is it the heat that kills them or other factors along with heat?

Apparently heat is the major factor..but product quality is also. If you have a module made by RichPorter...I'd be looking for an ACDelco.

**91dime** · 02-23-2016

It's an acdelco I bought from Rock auto, it does have a warranty option so if it's bad, I'll be using that.

**lionelhutz** · 02-23-2016

I've read all the troubleshooting and you have never mentioned if it has spark or not? The injectors won't fire if the ignition system isn't working right.

The coil has 2 connectors, right? Make sure the pink wires (original harness colors) are connected together by the coil and that both have battery power with the key on. I've seen a number of replacement plugs where the wires were the right colors but in the wrong locations.

**91dime** · 02-23-2016

I just tested to see if it would fire while adding fuel and it didnt even try to start, will a bad coil prevent the injectors from firing or did my new ICM already go bad? I have another laying around that i can test but im not sure if its good or not. I also tested another coil and no change in the condition, so either both coils i tried are bad or its not a coil issue.

And this is the case with my new plugs, the colors are wrong, but i made sure to match the orientation of the new and old plug to make sure i was connecting the correct OEM wires to the new wires.