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SC - 1st Gen (1992-2000)

Weird EFI Problem

Old Sep 23, 2014 | 04:27 PM
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Default Weird EFI Problem

Hey guys. I bought my 3rd SC in April and after driving her for several thousand miles, I've come to find a few problems that need to be solved.

The biggest problem is that since I bought the car, I've always experienced bog. I'd put my foot on the gas and instead of smoothly moving off, the car makes a sound that I can only describe as spitting gas out the exhaust. It will get up to speed and shift gears ok for the most part, but it for the most part always sounds like that, especially going from a dead stop or from 1st to 2nd.

Now initially I thought this was attributed to my driveshaft center support bearing being shot (I had it checked and know it needs changing). But then about a month ago, I stumbled across a thread suggesting to remove the EFI relay and put it back after a few minutes. I noticed the car ran considerably smoother after I did this.

The hesitation and bogging happened maybe twice in a 2 day period but other than that the driving experience was what I can only imagine a "factory SC" must drive like. What comes to mind to describe it is "instant torque" throughout the rpm range and the feeling was night and day. Whether I feathered it or put my foot in it it, it responded immediately the way cars are supposed to. Keep in mind my other 2 SC were basketcases and were done away with before I could even begin to fix them so I've never driven an SC that felt 100% but that was as close as any of mine have ever felt.

When my car began to run like before, I would take the relay out again but I noticed if I try taking it out after driving, it burns the crap out of my hand. I bought a new one from Lexus and the car ran better for a few days but the relay still heats up white hot and after a few days the car goes back to bogging.

None of the other relays get that hot and the fact that it gets better only for a period of time before becoming crappy again is stumping me. Any ideas??
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Old Sep 23, 2014 | 06:13 PM
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Following along from some suggestions I've received, maybe the ECU is learning from bad O2 sensors (or something else) after the EFI reset clears its memory?
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Old Sep 26, 2014 | 07:49 AM
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Wouldn't bad O2 Sensors throw a CEL? I haven't had that light come on not even once since I've had the car.
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Old Sep 26, 2014 | 12:12 PM
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Not necessarily. O2 sensors have to be pretty far gone, apparently, before they throw a CEL.
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Old Sep 26, 2014 | 03:05 PM
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The efi relay I imagine is supossed to get hot, but it does reset the ecu when you pull that more importantly.
the o2 sensors pretty much never through a CEL. if the are toast it can run rough. you can also disconnect the front ones at the plug and reset it, and if it doesn't do it again you know the o2's are making it act funny.
on another note it could be an ecu issue, but if you haven't done o2's thats a great place to start.
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Old Sep 29, 2014 | 07:14 AM
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Thanks guys. The first thing I'll do is the O2 sensors and if nothing, then I'll get the ECU repaired.
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