Sc400Jimmy

Hello,

I've been an avid visitor of this website for the last year, ever since purchasing my first Lexus. Now I've run into a problem that I can't seem to resolve and wanted to ask for your help please.

All of a sudden, my 92 SC400 Lexus has barely any power, a rough idle, and a very bad smell of fumes and as if something is burning. I can drive it but to get to a normal speed, I have to slowly get to it and not push the pedal so much because at one point, I saw sparks flying out of my rear view when I did that.

I drove it, slowly, to the mechanic. At first he said it was the cat, then he ruled it out and said it was a bad ECU. Everything I read on this forum pointed to it being a bad ECU too. The mechanic wanted to charge more than I had, so I brought it home. Ordered a used ECU, put it in, and I still have the same problem.

Now though, the car does not smell of really bad fumes as it did previously, but I still have a loss of power, a smell like something is burning, and a very rough idle.

Some people have pointed to the possibility of this being due to bad coil packs? Can someone please help point me in the right direction? Lexus wants to charge $$$ just for diagnostics plus $$$$ depending on what the problem is. I love this car. Thanks guys

Sc400Jimmy

I wanted to add: The smell of burning feels like it's coming from the bottom of the car, not from the front engine compartment; More like the middle of the car. The spark plug cables were replaced about 4 months ago, but not the spark plugs because according to the mechanic, they were new plugs and I didn't need any.

Also, when I drive it, it seems like its timing is off or something when switching gears in the first few MPH. It takes a while to switch gears, and then drops down to a normal RPM. The mechanic also said it was not the transmission

SC400slide

iTrader: (11)

Is it possible that the timing belt jumped a tooth or two? Unplug each coil while car is at idle and see if anything changes. Could definitely be coil packs.

Ali SC3

iTrader: (10)

you probably lost a coilpack, very common. the extra fuel from the coilpack not working hits the cat and then it starts to heat up and burn so that is probably what you are smelling.

Sc400Jimmy

That makes a lot of sense. I've looked everywhere for videos or instructions on how to replace these coilpacks on the 92 SC400 and couldn't find any. Do you know of any, and if not, do you know of a car that will closely resemble this car in replacing the coilpacks?

Sc400Jimmy

Also, another thing I noticed. I don't think this car had coilpacks, but I may be wrong? I called autozone asking if they had coilpacks, and the only thing they said this car has is an iginition coil. Would or could that still be the problem I'm facing?

SC400slide

iTrader: (11)

Ignition coils are the coil packs. Auto Zone will have them.

Sc400Jimmy

Oh ok thanks. They said that the car only takes one, is that all I would need then to buy? On this video, they have 6 Coilpacks so I believe I'm looking at a video that doesn't apply to my situation. Do you know where this ignition coil is located?

I'm so sorry about the newb questions, but I have to start learning how to work on my own car because I love this car, and every mechanic I take it to, returns the car to me with more problems. Thanks

SC400slide

iTrader: (11)

Your SC400 has 2 coil packs. (I guess they can be called ignition coils as well) ES300 is completely different as it is a 6 cylinder instead of the SC's V8.

Ali SC3

iTrader: (10)

sorry coil not coilpacks technically you are right. non vvti 1uzfe will have 2 ignition coils (we just generally call them coils or coilpacks).
the later vvti ones will have 8 coilpacks instead of the 2 ignition coils.

It is a v8 so you have 2, and you will have one on the drivers side and one on the passenger side, usually the drives side one fails.
you unplug the 2 wire connector going into the coil (DO not pull the single spark plug wire off of it while it is running or you can shock yourself, pull the small 2 wire connector) and if there is no change in how the car starts runs and drives then you know you have disconnected the faultly one. plug it back in and verify there is no change and that is the one you need to replace.

If you unplug one and there is a change, as in car runs worse or wont even start, then you unplugged the good one, so plug that one back in and try the other one.

If both are good (unplugging them makes the car worse), then post back it is something else then.
If you unplug one and there is no change, then that is the one you need to replace.
you can get it at most part stores try napa or online, or even a used coil can get you by from a SC400 or LS400.

Sc400Jimmy

Thank you guys, really, SC400slide and Ali SC3, for helping me out with this. I'm going to go to AutoZone now and buy the ignition coil for this car and then try to see if I can find where it is and how to replace it when I get back. I will definitely keep you updated. Thank you again

Jimmy

Sc400Jimmy

Hello,

I unplugged the connector going into the drivers side coil and the car wouldn't start. So I'm now looking for the passenger side coil to test, but I can't find it. Can you help me locate the passenger side coil to test with? Thank you

Ali SC3

iTrader: (10)

might be by the radiator I think or towards the intake box, don;t have an sc4 to tell you exactly but it looks just like the other one.

SC400slide

iTrader: (11)

Then your drivers side ignition coil is working fine. In very rare cases does the passenger coil go out only.

Sc400Jimmy

I'm not sure what else this problem could be (I'm still unable to test the passenger coil but if it rarely goes out, I'm going to rule out the ignition coils). Could this just be a spark plug issue then, judging from the symptoms as described above? I have no check engine light either