SC400slide

iTrader: (11)

Did your mechanic ever test the MAF? Did he go through all of the possibilities mentioned in this thread?

Sc400Jimmy

This has been the worst luck. Today, i got my car back and everything was OK. They showed me the distributor caps they were broken, there was also a problem with a wire that burned up. All was well again. I drove it out of there on my way home, everyone was OK.


All of a sudden, the same thing happened. I'm back to ground zero. Cats were burning red under the car, I loss all power and could not drive under 5 miles per hour. I'm feeling really defeated, what in the world is wrong with my car...... MAF changed, distributor caps, ignition coils, spark plugs, spark plug cables, ecu changed out with a used one... Any ideas

SC400slide

iTrader: (11)

Might be that the distributor unwinded again and broke...something could be causing that. You're onto something I think.

Sc400Jimmy

Do you have any idea what may have caused it, if that's what ended up happening?

Ali SC3

iTrader: (10)

did you change the rotors inside the caps? If the cap was done I can almost give you a guarantee that the rotors are toast too.
sorry I am catching up a little late here, what year is your sc400 and what year ecu did you buy. on sc400 you can only switch certain year's ecu's.
like if you have a 92-94 you cannot use a 95+ ecu as they went from batch fire fuel to sequential fuel injection. meaning if you use a 95+ ecu you get double the fuel as well as other weird things.

what wire was burned up? do you have any codes?
check the cam sensor wire the runs by the drivers side distributor for damage. it sort of comes out of the block and goes behind the belt into the distributor area.

rarely the ignitor plug can go bad or a loose connector on them, check for loose connectors on the coil or cracked ones, also the TPS connector.
any cracks in these connectors will cause a bad connection.

could also be something mechanical like a bad injector or something but I would rule out the ignition electronics first.

Sc400Jimmy

Hey Ali thanks for your input.

This is a 92 lexus sc400 with about 120,000 miles in it. I believe they changed out the rotors inside if the caps. The ecu I ordered was from 1994.

I'm going to ask them about checking the cam wire like you mentioned above.

I'm still here with them. It's just strange that the caps were replaced and the rotors, everything was fine and then all of a sudden on the way home, the same thing happens. It's as if it is dumping too much fuel and also the car has no power.

Ali SC3

iTrader: (10)

if there is no difference I would swap back to the original ecu, or maybe open it up and have a look while its out of the car just to rule it out. the possibility of getting a bad one is well, the same possibility as your old one being bad.

if it doesn;'t happen at first and then happens I would stlil suspect the ecu I have heard that said before it seems to be worst when it warms up.
it is even possible to have an issue with the coolant temp sensor. are you sure there are no Check engine light codes? make sure the bulb works when you first put the key on it should light up and then go away. if it stays lit then we need to pull the codes.

Sc400Jimmy

Finally, the car is fixed and better then ever. When I took it back to the shop, strangely the passenger side ignition coil that they had just put in the day before, was out again. They pulled the coil and tested the wires leading into it. The ground cable was not giving any signal. They thought that was strange.

So we checked the kick panel ignition related fuse
and saw that there was a lot of corrosion on it. We replaced the fuse and now the ground wire was working again. We out in another ignition coil, again since the new one was now burned out already) and voila, the car was good again.

So in short, still find it strange that a bad fuse could have been what started all this. One fuse causing the ignition coil to burn, the the distributor caps, the rotors, and so on. So I'm hoping this time the car is good for good. She's running beautifully again, she's alive, and survived a near death experience.

Thanks everyone for your input in this thread. So for future reference, guys check the fuses just incase, even if they do not seem burned out. These are older cars.

SC400slide

iTrader: (11)

Wow! So lesson learned, go through the necessary "trouble-shooting" steps. Even a fuse can cause armageddon. Glad to hear your SC is healthy again!

Sc400Jimmy

Yes, huge lesson learned! Thank you SO much for your continued help and everything you did on here SC400SLIDE. I learned a lot with your help and feel I'm in a better position to trouble shoot things in the future if they ever come up again. With only 119k miles on her, she was too young to go and I'm glad she made it! :-)

10708sbway

I had a question to anyone who might have the answer .my 95 sc400 does not have coilpacks it has 2 distributers and it out of no were it started to idle lower and rumble like it lost power