Vortec 454/4L80e HD swapped 1999 Tahoe OBS

[bigfootchiro]

On my way home, truck is running like shit again. Have no power anywhere in the RPM range, just runs like a slug. Then the TC doesn’t wanna lockup, the about 2 miles down the road it kicks me down from 4th to 3rd! After that, it starts up shifting hard. Get to the gas station, turn off the truck, put some gas in, start it up, and it shifts fine. I’m at a loss... have no idea wtf is happening

 

[randeez]

you should swap in an old reliable 350 vortec

 

[bigfootchiro]

you should swap in an old reliable 350 vortec

I hate you just a little bit right now

 

[randeez]

who's doing the tuning? and with what - hptuners/efilive?

 

[bigfootchiro]

who's doing the tuning? and with what - hptuners/efilive?

No tuning yet, just the stock 454 PCM out of the RV

 

[bigfootchiro]

Found this diagram. Looks like a common connection/ground with the MAF and the ICM. Potential suspect?

 

[randeez]

are you using the stock o2 sensors? possible they arent pinned the same as the RV o2 sensors/ecm. could be back feeding something? i dont know what else you may have carried over and used or used your original sensors

cant really read that all that well

 

[bigfootchiro]

are you using the stock o2 sensors? possible they arent pinned the same as the RV o2 sensors/ecm. could be back feeding something? i dont know what else you may have carried over and used or used your original sensors

cant really read that all that well

That’s a good idea. I’ll check the pin out diagrams, but I think they are the same

 

[bigfootchiro]

Found a bad ground in the area of that diagram above. Just noticed it! Previous owner thought it would be a good idea to “hook” the wires together and put shrink wrap over it, but never heated it either to shrink around. Didn’t even twist the wires together. Throwing a new ground wire on and we will see how she runs

 

[Sam Harris]

Found a bad ground in the area of that diagram above. Just noticed it! Previous owner thought it would be a good idea to “hook” the wires together and put shrink wrap over it, but never heated it either to shrink around. Didn’t even twist the wires together. Throwing a new ground wire on and we will see how she runs

View attachment 225145

Sweet! Good find!