With the help of Voss (really kool kat), I have finished the install of an engine upgrade from the 4.0l to the 4.2l.

The car ran for days ...began to stall immediately after I added gas in the tank

I need help resolving the following..

- The engine starts but it stalls during idle
- The throttle body has been replaced
- I have had the ECU checked and it has a bad processor or "processor failure" as I was told
- A new ECU has been purchased but it needs to be flashed to my car.

The local dealership will not take this on...
I have the IDS software but I don't know how to use it for this
The dealership told me IDS does not recognize my VIN because of "sub-sections needing to be added"

What can I do to flash the replacement ECU so I can get this car driving again?

codes p1797, p1638, p1642, p0052


KT

 

I did not know it was possible to put a 4.2 in a 4.0 car. I did not think an ECU from either motor would work with the other. Wiring issues? Trans Module diff?

 

Are there not CAN/BUS (using correct words?) system diff from an 4.2 to 4.0 cars such as Jag Specialties has not mad a conversion kit for GM LSx motors for 03 and newer xk8's???

 

I thought there was a post about using the 4.2 short block only. on the earlier series

 

I am only using the 4.2l block with modifications using 4.0l parts.
The cable interfaces match as well
The car ran for days ...began to stall immediately after I added gas in the tank
Then the focus turned to the Throttle Body and the ECU