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Extremely rough idle and lots of mechanical noises - resetting computer solved it

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Old 06-12-14, 10:16 AM   #1
Finn
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Default Extremely rough idle and lots of mechanical noises - resetting computer solved it

Cheers all!

OK, here's what happened:

Last Saturday I pushed my -91 out from the garage - pushed did not start - to make room to work on my Harley. After few hours I was done and I started the engine and drove said 15 feet back in. Engine was running slightly faster idle when I shut the engine off.

Today I went in the garage to take LS out. I started it and it did not start as it usually starts with ease but...well...differently. I noticed immediately that the idle was very, very rough and there seemed, well, that's what it felt, to be all sorts of mechanical noises. I shut the engine off almost instantly.

After a while I started it again and it was slightly better but not what it should be. I listened to the engine idling and reversed the car out and shut it off.

Something in the back of my head told me to reset the computer and I pulled battery cable off and let it sit for a while. I then put the cable back on and started the car. Most of the roughness and such were away and I went for a ride. Now after 20 miles or so computer seems to have re-learned and 1UZ-FE purrs again smoothly. With a tick-tick but smooth nevertheless.

QUESTIONS:

What exactly happened on Saturday when I shut the engine off in fast idle? Was it in some sort of warm-up phase that messed up the computer?

If I had not reset the computer today would it have learned and cleared the situation by itself?
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Old 06-12-14, 02:57 PM   #2
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have you had your ECU capacitors changed?

i don't like starting a car just to move it a few feet then shutting it back off especially when cold. i like to keep the car running for at least 5 minutes for the oil and fluids to circulate. this is where the most wear and tear happens on your engine.
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Old 06-12-14, 05:56 PM   #3
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Probably did not give the alternator enough time to recharge the battery correctly. I'm with timmy on this one, I also let the car run until it's at least warmed up before shutting it down.
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Old 06-12-14, 08:21 PM   #4
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I don't like starting the car for 15 feet either but that was a must - now I know better ie. either let it idle longer or take it for a spin.

We do not seem to have ECU capacitor problem on this side of the pond. Never heard anyone mentioning that here. Mine - apart from this hickup - works like a dream.
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1991 Lexus LS400 1UZ-FE | 1992 Audi 80 2.0E | 1978 Corvette 427" | 1986 Corvette 383" | 1992 Jeep XJ 4.0 HO
2009 Yamaha FJR 1300 | 1993 BMW K1100LT

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Old 06-12-14, 08:21 PM
 
 
 
 
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