Details on truck: 06 gmc Sierra 1500 Denali. Tuned, headers, CAI that's it.

Long story short, I did the big 3 upgrade last night and now have no spark when trying to fire. All my connection are clean and tight I double checked. I have checked ALL fuses and they are good. Now here's the kicker, it will randomly have spark for about a second and try to fire then nothing it just stops sparking. It's getting fuel, I can smell it. Haven't been able to check my fuel pressure but it was fine before. Any help it's my DD and I go to worm tonight.

I have checked the crank sensor and changed it to be sure. The power wire is getting 12 volts and the ground is good. Now the signal wire I read you manually turn the crank and it should read 10volts but I'm only getting .03 or so. Even when you use the starter (says not to) still only 4 volts.


How I have the big 3:
+ Alternator to battery
- battery to frame
- battery to block
- battery to core support (factory one still)

 

Anyone?

 

Well obviously that shouldnt happen....check all the fuses in the underhood box and if they all look good then disconnect the wires you added.

 

What about Block to body?

Did you remove any of the factory grounds or go over them?

The Ground cable should have a little EBCM module zip tied on it. If that is missing you will have a similar problem.

 

Don't have a block to body ground as my factory one didn't. I removed the factory grounds only from battery but made an identical copy of them and replaced them with bigger cable. I made sure the module on the ground cable was replaced, it's there around one of the bigger cables but not all of them since it wouldn't fit around all them.

Only wires I replaced were the battery ones, didn't touch the any others.

 

I triple checked every single fuse all good, I am going to try putting all the factory wires back on for the battery and try that. Just doesn't make sense I only have no spark and nothing else. But will randomly get spark sometimes but stop

 

Replace the factory ground from the battery to the Block and frame with the EBCM and see if that fixes your issue.

I had one that was cut and tried to patch it together. I never worked until I replaced it with another OEM one.

 

So just put the factory grounds back in place you mean?

 

Yes.

 

OK so all the factory wires are back on but still nothing. We tested the coils and still no spark but there getting power. We are thinking it could be a security issue any one have any other input

Update, so found the problem I think. The ignition coil ground wire (PIN A) has ground when the key is off, but switches to + 12 volts when the ignition is turned on or cranking over. Shouldn't be doing that, had another buddy helping me who has a Denali as well and it doesn't do that it stays grounded the whole time