1996LS

what are the signs of a bad computer? ive replaced all spark plugs and wires cap and rotor but it still says misfire on cylinder 2 and 6 now im gettin a terrible idle and white smoke it smells like the car is running rich. If i pull the battery post off for a while it resets and the runs ok for a minute then goes back to rough idle or miss and i cant hardly accelerate also the trac off light blinks and the engine light comes on someone please help me the car has 208k and i dont want to start sinking a lot of money in it doing guess work

PureDrifter

iTrader: (10)

did you check the coils...?

3UZFTE

Read the codes, the engine is tell you that it is storing codes, don't guess.

Banshee365

Oh boy... Been there done that buddy. Some '96 ECM's seem to have a certain lifespan. We swore our '96 was destined for the junk yard by the way it was running. Rotten egg smell out of exhaust, either super low or super high idle. Reving up to 2,500 rpm and bouncing that by itself, a engine coolant temp circuit malfunction CEL that wouldn't go away, near impossible hot starts, and the list goes on and on and on. After troubleshooting alot with a seasoned Lexus tech he suggested I start looking at the ECM as the source voltage on the ECT circuit was lower than it should be. I bought a used '96 ECM with about 72k on it for $200 and this car is like brand new. It runs like it just came off the showroom floor with 210k miles. Does your car burn oil or knock/tick, etc? If not, I say it's worth fixing. The ECM is an easy DIY job. The guy I bought it from sells Lexus parts and he said he sells lots of 94 and 96 ECM's.

To answer your question, there is no way to tell. There isn't an ECM check engine light. In the Lexus factory manuals you will follow certain replacements or procedures and usually the last fix is to replace the ECM if nothing before helped. Give us each numeric P0*** code that you have to get an idea. I agree with checking your coils, but if you disconnect your battery and it runs better after that and get's worse I would also start suspecting electronic issues. Are you sure your caps/rotors were reinstalled correctly? If it runs fine after you reconnect the battery they must be installed correctly.

1996LS

thanx a bunch im a noob to this site and i feel a lil better about the computer being the prob my friend highly reccomended solo autoparts in miami (305)387-7759 they specialize in ls400 ecm's so i removed the computer and will be shipping it monday and i will let everyone know what happens thanx again

1996LS

has anyone done the egr block off on 1996 ls400 and if so what are true results

1996LS

it cyl misfire on 2 and 6 but i changed wires and plus too also caps and rotors as well

RA40

iTrader: (6)

How was it running prior to the parts swap?

Banshee365

I'd also like to reconfirm that the car runs okay for a little bit after you disconnect the batteries? When it starts to relearn it develops problems? If it alway's run's bad check for connections and such.

1996LS

1 at a time yep

1996LS

yeah i have the computer out and ready to be shipped and tested (by solo autoparts) they say if nothing is wrong they will let me know or fix it for $200

1996LS

wuzzup guys soloautoparts.com hooked me up my baby is back in action from the computer rebuild now i have stuff working that wasnt working before!! that rebuild cost me $260 total shipping and all! they fixed it and had it overnighted back to me from miami to mississippi ask for alex

PureDrifter

iTrader: (10)

good to know, congrats!

1996LS

took her out for a long drive and shes puring like a kitten off to next project the stering wheel and seat belts in the front any tips

1996LS400

I am having the EXACT same problem!!!! White smoke and it it smells like it's running rich and rough idle. I havent replaced the caps/rotors or plugs yet but will hopefully this weekend. If no go after that I guess the computer will be next.

Here's the link to my post:
http://us.lexusownersclub.com/forums...howtopic=64398