lexsc92

Yeah I've had the ECU out, didn't see any moisture down there :/

Also there's no sweet smell, and the coolant level hasn't dropped. I've had a compression test done and all cylinders were good. Also the car does misfire sometimes with no smoke at all. Only seems to smoke when cold because the car is dumping more fuel.

There seems to be few things the car does...

-Cold start after sitting several days: runs extremely rough, chugging idle, etc. doesn't go away, but go start the car 4-5 hours later and it will be much better.

-cold start after only sitting one or two days, runs rough, but I can "rev" the problem away and idle will smooth out,

-Car will sometimes have a wandering idle once warm, especially when coming to a stop. Idle will dip randomly. Once I get the the gas enough it takes off full power no problem, partial throttle will sometimes hesitate.

lexsc92

Another update today:

Car started up fine, maybe a little hesitant at first but no rough idle, didn't surge at idle. Did feel a couple hesitations at partial throttle.

The interesting thing is...the egr is one of the things I've been meaning to check. I popped the hood, tapped the egr with a screw driver and the car died right away. did it a couple more times to make sure it wasn't a fluke and it died each time.

Should that happen when you tap the egr, or does this confirm I have an issue with it?

lexsc92

Issue has hit its peak now, and is no longer just intermittent. It does it right at start up and is no longer drivable.

Lots of white smoke at start up, heavy fuel smell, can even see some fuel in the exhaust pipe, very rough idle.

It's definitely an overfueling issue. Dead miss in cylinders 2 and 8.

So it seems both of these injectors are sticking wide open and flooding these cylinders.
So either the ECU driver that controls these cylinders (they use the same one) are totally shorted, or there is a short to ground somewhere in the wiring harness.

Any advice to testing this?

dsolis12

OK............this is exactly what happened to me. It got so bad I had to take it in. The mechanic found #7 spark plug wire was arking under the fly wheel cover. I went ahead and replaced all of them. Runs great now.

ihiryu

iTrader: (7)

Yeah I've had that issue before too, mine was a spark plug wire got eaten by the cam gear. Did you ever replace the ECU though?

I know a symptom of a bad ecu causes a lot of smoking on start up.

lexsc92

Yeah I did try a ECU, but I think lots of bad ECUs are floating around. So I guess I'll find give a try and find another one :/.

lexsc92

So I ended up getting a noid light on the #2 injector. sure it enough it stays bright without any pulsing. The light also came on with just the key in the "on" position.

So I guess that confirms injectors 2 and 8 are either grounding out somewhere, or the ECU driver is dead for those particular injectors.

nlc

Its ur ecu...i had that same problem. The previous owner kept driving it n blew the headgasket...n i switched ecu n motor n now ive been driving fine since march..

nlc

Idk what it does to the injectors but i think they jus stay open cuz i let it idle with the bad ecu after i swapped a motor n i watch the gas drip out the tail pipes..with tons of white smoke like i was seafoaming the car. When i took of the oil cap off it smelled like straight gas also...i tried 3 different ecu's n i got the same thing..i wish i knew how to fix these ecus cuz i got like 4 of them n there all bad.

Hope u find out whats going...i kno it can be frustrating. GL

lexsc92

Yeah I think that was my problem to begin with. I tried another ECU and it still ran like crap.

Then I had this one "rebuilt" but I don't think they did a great job obviously.

Lots of bad ECUs going around I think.

lexsc92

Well looks like it was indeed the ECU. Popped in the new one, verified the ground was good with a noid light and fired it up and idled smooth.

Car blew a ton of white smoke though. That normal from all the fuel washing down the cylinders, and the new ecu calibrating, etc?

lexsc92

I can 100% confirm now the ECU was the problem. Seems the ECU has calibrated now after driving it for a day and it doesn't blow any white smoke at all on start up now.

Seems ECU failure is very common on the early 90s Lexus cars.

Next I need to change the oil as it is diluted with fuel. Also once the car warms up completely after about 20 mins, I noticed a very occasional miss only at idle. I'm thinking the overly rich fuel mixture may have affected some other things too. So I'm going to check and clean the EGR, then check o2 sensors if that doesn't work.

lexsc92

So it looks like I was battling two separate issues. Which is why I got such random symptoms.

First off the ECU fixed the injector issue, and the car fires right up and runs great now.

However, once the car is fully warmed up it's still having an issue at idle only.
When it sits for a while in traffic or in park the idle will randomly drop, almost stall, then stabilize. It does it randomly with no pattern. Anyone have any ideas? I already cleaned the IACV.. I should add there is no hesitation at all the car runs great, just randomly bogs down at idle and almost stalls.

Toyboxx

iTrader: (1)

I'm having most of the same symptoms, mainly just the bucking & hesitation. Originally when I got the car, whenever it was cold it would missfire occasionaly an shake inside the car. I then seafoamed it, and the cold starts are fin now, no missfiring while idling. But now, the intermitten "buck" isn't so intermitten anymore. Happens everyday at about half throttle or more. SO I've bought some CRC MAF Cleaner this morning, and I'm going to attempt to clean the MAF and see if that doesn't help.

Sorry to thread jack