tcramer49

Hello from Okla. New to th forum so be gentle. I'll try to make this short. I have a 1997 ls400 with less than 80k miles. Everything worked great until I wrecked it and tore up the left side. I looked for a doner car for body parts and found a 1996 ls400 with a blown head gasket for $1500 and my son and I went to look at it and we found that the body and interior was so good after 240k miles he talked me into letting him just swap the engine and transmission, only took him about 3 days to complete the swap wiring harness and all from the 97. Wouldn't start so switched the ecm behind the glove box now starts and runs for about 5 seconds then dies. A friend of his says it needs to go to the Lexus dealer to be reprogrammed. Anyone have any ideas as to what I need to do to get this car running or would it have been easier to just replace body parts and paint? I really love these cars and my wife wants her car back. Thanks in advance for any help.
P.S. The 1996 has traction control and heated seats the 1997 does not if that makes any difference.
Thanks
Cramer

dicer

The better deal to do would be to transfer all the engine sensors etc. from the 96 engine to the 97 engine.
If the 96 was running good there was no reason to bother right now with all that work.
Put all the 96 parts back in the car, wire harness too. Make the engine have the right parts not the car.

tcramer49

You mean put the wiring harness and sensors from the 96 engine on the 97 engine. Okay I'll tell my son that.
Thanks
Cramer

Yamae

Judging from your word "5 seconds", your car may be going into the inhibiting mode which is explained
here (post #118). Check the circuit opening relay behind the battery. If it's cutting off in a few to several seconds, check those sensor's connection first. I imagine one of those sensors is not connected or there must be some damage of a wire or a connector.

dicer

If you are putting a newer engine in the car, you adapt the engine to the car not the car to the engine. There can just be way too many things to have to change to adapt the car.
I don't know about the 96 and 97 but a lot of newer cars all the electronics inter communicate with each other. I don't know what is different electronically on a 96 to a 97, if they were the same then there should be no reason to swap a harness.
If the harness's were different then there are likely many other things that are different as well. And again adapt the engine to the car, put the original ecu back in and anything else electrical that was changed on the car.

tcramer49

Okay thanks for the replys I'll keep you posted.
Thanks
Cramer

tcramer49

Just a quick update. My son took the car to a Lexus dealer and they told him what dicer said you have to use everything from the 96 car on the 97 engine and transmission. There is an immobilizer on the 97 wiring harness that keeps you from using any of the wiring harness from the 97. So I am going over to my sons house soon and stay a few days to get the harness changed out. I'll let you know how that goes.
Thanks
Cramer

dicer

Thank you, and do keep us posted on the progress.

tcramer49

Sorry it took so long to get back to you guys but been busy and my son had another project that he had to finish. He swapped out the 97 wiring harness and replaced it with the 96 harness and it started right up! Hooray! So in conclusion do what dicer said adapt the engine to the car. Thanks for all the great help.

Cramer

jaaa

Lots of good info on this forum and dicer is a good one.