els-

Hi we have a truck that had been water damaged, its a 1998 chevy k2500 that had a 6.5L

I had spare engines and parts and the truck is rust free so I started swapping.

I have a 1999 5.3 that was from a 4x4 truck but 4l60e trans.
I have a 4l80e 4x4 trans in the truck, and purchased a 6.0l computer that had a 4x4 4l80e behind it.

Im assuming the computer will work but the engine will run rich.

Motor is mostly all in but I am having a problem with the wiring. I want todo a stand alone harness for it to be 5.3/4l80e with the 6.0l computer. But all I have been able to find is different year pin outs.

6.0l computer is from a 2001 k2500. 5.3l engine, wiring and computer is from a 1999 k1500.

If anyone could be of any help that would be great as I dont have anywhere even close to local or the next province over that would even touch the harness If I sent it out.

vinceI

iTrader: (5)

Some good info here... http://www.lt1swap.com/99-02_vortec_pcm.htm Hope this helps a little.

els-

Thanks I have seen that. I can mostly run everything as it is. Wish I had a dash and column out of a 1999+ truck.

I think my misunderstanding is with the power wires. Pins 20/57/75 need fused power from the battery, while pin 19 when given power should start the motor correct?

vinceI

iTrader: (5)

20 and 57 will have fused battery voltage at all times(these wires are orange in the harness.) 75 and 19 will only give voltage to the pcm during key on and cranking (these wires are pink) Also all the pink wires that go to the injectors and coils will get 12 volts key on and cranking.

els-

Ok so wiring it up just to move it in and out of the shop. I should run power to all the orange (fused) and then all the pink (fused) run off the ignition switch. And then the rest takes care of itself via the computer. Makes more sense now.

vinceI

iTrader: (5)

correct that will power the ecu and you will need wiring to a starter relay to crank it over.

els-

Alright perfect, I should still have the original starter wires on the harness still, I should be able to find it and splice it in somewhere on the on key side from my 98 column.

vinceI

iTrader: (5)

Its a big purple wire in the truck harness just hook it to the wire that gets 12 volts only while key is in crank position coming from your column.

els-

Alright, I've been waiting on clear print outs for the 98, it was diesel and no one seems to have any diagrams on it. I'm assuming they were similar wiring to the gas trucks I also have a gas truck for parts I could rob wiring from.

Thanks again for the help.

vinceI

iTrader: (5)

No problem, good luck with the swap.

els-

Finally had time to work on it again. All the pinks are wired and all the orange and purple brake wire are wired together. Starter turns the motor over, I'm getting power to the coils but no spark. This is with the original computer to that motor.

At abit of a loss.

Bdiddy

iTrader: (5)

You have to get vats deleted in the tune to make it run. Sounds wired ok but it will never spark with the computer having vats on. (Vehicle anti theft system)

els-

Would there be a way to bypass the vats right at the computer, I know by the key cylinder it could be bypassed with a resistor.

ijimmy

no sorry . if it runs while someone is spraying start fluid into throttle body , it maybe a vats issue , vats disables the negative side of the injectors ,,

Bdiddy

iTrader: (5)

I think the pcm has to talk to the bcm and stuff. In a swap situation with no body control module I think having vats deleted is the only way to go. I got my ecm reflashed by lt1swap.com and I was able to start my 5.3 on an engine stand. He deleted my vats. It will never start with vats enabled.

els-

Most of my problem is due to the fact that Im so far upnorth in canada common stuff like getting the ecm vats disabled is 3-4 weeks away if I sent it out tommorow.

I know theres a combination of resistors, 1-15 that can be spliced in under the column and it runs back to the ecm and sends the signal to it.

But Ive put the motor into pretty much a shell of a truck, there wont ever be a bcm as its all switches on the dash for lights, fuel pump etc.

I couldnt find anywhere in the diagrams the wire that runs to the vats and ecm that I can put a resistor in. I think thats the key to all of it but am unsure.

els-

I have found this, but I havent been able to find where the output to pcm goes for hours now. Im not sure if it goes to all the power wires, or only the orange ones, or only the pink, or one or two certain wires.

I can make the chip easy enough, but information seems to be lacking in certain spots about alot of this stuff.

76larkman

If im not mistaken your going to have tranny problems if using diesil one behind gas motor. Valvebody and solinoids are all different than gasser ones. torque convertor different stall as well. A friend went thru this ended up getting gasser tranny as was cheaper than rebuilding with correct parts.

Envy

Pretty sure all 4L80Es are the same, depending upon year, there are some changes. I think the difference is in the torque converter. I'd imagine if you re-stalled it to the appropriate speed, you'd be fine.

76larkman

i talked to my tranny guy thats been doing them since late 70"s says he had a customer doing swap from 6.5 turbo diesil to gas. gearing ratio in the tranny is favorable to way diesil revs to get it moving. he also said wouldnt shift even manually. im getting ready to do same diesil to gas swap 97 chevy 3500 hd. going with a 6.o and 4l80e just buying a wrecked truck for everything to be easiest.