What’s up peoples. Hope everyone is having a blessed one.
I recently replaced the ECU/ECM in my 1996 LS400. It was reading the ECU was bad so I bought a used one, same number and everything else. I replaced it and now my LS400 is running super rich. It’s throwing out a lot of white smokes from the exhaust pipes. I ran and it killed a qtr tank in no time. Strong fuel smell when I start the car. Do you guys think the used ECU I put in the car is faulty or do I need to try out another ECU other than the 89661-50303 I have. Thank you in advance.

 

All ECU's fail, so a used ECU does not mean a working ECU.

See:

https://www.clublexus.com/forums/ls-...capacitor.html

 

Thank you. The issue was it did not start before but at least now it starts and now I have that issue with this ECU lol. Time to take it off and inspect it and go from there. Thank you again for the link as well.

 

I worry that copper traces are already damaged. It is the often case to be so when capacitors are not replaced for many years. QAS capacitors fail faster than conventional electrolytic capacitors and the leaked liquid is the strong alkali which eats up copper traces. The conformal coating sometimes prevent it but you can't expect it a lot since the coating under the capacitor is thin or almost none.

 

Exactly. You (he) got another 30 year old computer to replace the 30 year old computer that was already in the car. Time to dig deeper.