Thought I should throw this out there since I was given some very misleading information and couldn't find what I needed in searches of forums today. This is on an 03 with a manual transmission, I'm told it can be different in the later years. All that is needed to get the engine running, provided you have the stock harness and all the sensors still in place on the engine, is three wires. Near the ecm harness, there are two wires that branch off towards the drivers side fender, one has a spade plug on it and the other is a black wire with a ring terminal. The spade plug goes direct to battery+, the ring terminal goes to ground. The third wire needed is pin 32 on the 50 pin connector (green w/black stripe), this one needs 12 volts whenever the key is on and in start (no different than a fuel shutoff solenoid).

That's all it takes, seriously. So much for a 12 valve being easier to swap huh? You still have alternator, grid heaters, starter, and gauges with any engine you swap.

 

But you would still need the harness for any tuners/programmers to work, so if you wanted to keep it stock then it would be great

 

Only have to tap three more wires off the ecm to make the obd port active. This is way simpler than it is made out to be. The only reason I can see spending $1000 for the painless wiring harness is if you just don't have the stock harness.

 

That is some thing to think about. I m putting a cummins in my 86 chevy and was gong for a 12 valve for the lack of wireing but that sounds pretty easy.

 

The painless harness is actually more involved than the O.E. harness. You do not need to do anything with the alternator wiring as it is ECM controlled.

 

Anyone know which three wires?

 

Thanks for the info ive been looking at the engine i have sitting in my shop thinking wow what doo all these wires doo

 

i could use some help are you still on this site