Finicky motor swap issues

[Jeremy @ No Limit]

Ok I'll try to keep this short. I bought a 2006 reg cab that blew a head gasket, kid took it to a local shop, then he decided he didn't want to fix it so they slapped the head and can back on. It sat at their shop for almost 2 years. Coolant on the cylinders of that head rusted bad. So I bought another motor (2007 motor), had a good bit of work done to it and swapped it in. Along with a 4wd tranny since it was a 2wd. 300/150 sticks from Rykan and a billet 366 which I plan to add big LP to. Anyway, I'm at the point where I'm trying to start it. It starts and runs absolutely great.....for about 4 seconds. Then it's like you pull the plug. Just dies. Every single plug and wire was taken loose on the truck when I got it so I've gone over them multiple times. I've even swapped to a 2007 PCM. Still does the same. Here's a kicker.....I can't get anything to connect to it to pull the codes.

Calling my 6.0 gurus. What have I missed?

 

[DEEZUZ]

Sounds like 5v ref line is being pulled down.... Start by unplugging each 5v sensors at a time and see if it stays running..

What about cam and crank sensors? Have they been changed or rust jacked?

 

[Super Diesel]

You check your spark plugs? I'd start there. :morons:

 

[Constructionworker]

Does it start right back up after it dies and run another 4 seconds before dying again?

 

[Jeremy @ No Limit]

Sounds like 5v ref line is being pulled down.... Start by unplugging each 5v sensors at a time and see if it stays running..

What about cam and crank sensors? Have they been changed or rust jacked?

Will do. Cam and crank sensors should be good. I heard it run a good bit before I bought it.

Does it start right back up after it dies and run another 4 seconds before dying again?

Yup sure does

 

[powerstrokedkid87]

you didn't mention so il ask, did you check all the fuses under the dash first? I know we have had a few trucks that blow out the 10am fuse for the obd. I think first thing you need is to be able to monitor some things to see whats dropping off when it shuts down.

 

[Jeremy @ No Limit]

Found the issue after some head scratching. Rykan dropped me the info. Had am injector coil shorted. I'm pulling them all and sending to him. He's going to work a little magic on them

 

[cRaZy8]

Glad to hear you found it!

With the coil shorted, was the FICM sensing the dead short, and shutting the injection cycles off? Curious to see what factor was making the engine shut down.