I have an 2001 LS 430 and I switch the motor and transmission from a 2004 LS 430. I change the ecu to a 2004. My car turns on but turns right off. What can i do? Or does anyone know what might be the problem..... Please help

 

Was engine good when it was removed from the initial car? Check and ensure MAF is connected, that'd be a good start.

 

The 2004 might have significantly different wiring harness and systems. Could be a big problem...but I am not an expert. I'd go down and see if I could talk to one of the top Lexus techs for 15 min down at the dealer - even if I had to pay for their time. .

 

@ ultm8MIND the motor was working fine on the 2004

 

@ jabberwock i change the wire harness to 2004 and the eng computer i was told by a friend that on 2001 the mobilizer is together in the eng computer and in the 2004 is not that im going to hav to buy a mobilizer for a 2004 i dont know if its true ???????????????

 

I'm not sure about the Lexus but I did motor swaps like you are doing in BMW's (different year and model 740i into a 540i car) and I may know what your problem is. Did you swap everything from the 2004 to the 2001 (MAF, TPS, throttle body, etc. etc.)?

What I did was leave the original ECU/ECM in the car as well as the original wiring harness and take all of the computer controlled parts (there's not that many, mainly anything on the plenum/intake system, MAF, TPS, etc.) from the old motor and put them on the new one so the car knows what to control. If you put the 2004 ECU/ECM in the 2001 and used any of the 2001 controls on the motor, that may be your issue. The 2004 ECU is not "talking" to the 2001 parts.

Mechanically the motors are the same so this should work. I don't think you should be using the 2004 ECU because there are probably some 2001 parts on the car that its not synced to control. If it were me I would put the 2001 ECU back in the car and take your original harness and anything that's connected to it and put it back in the car. My bet is it will fire right up.

 

Jay - did you ever get the car running? If so what was the issue?