2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Low Idle with lights on

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Old Nov 10, 2008 | 11:13 PM
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From: washington
Low Idle with lights on

Ok now my idle is soo low during i turned on my lights. When i turn on my lights or applied my brakes my rpm goes down during idle, i step on the gas to reach it to 2500rpm and let it go to idle then my rpm wents down to around 300rpm. But when i turned off my lights the rpm still low but when i rev it to 2500rpm then let it go, my rpm shoots down to a nice 900-1000rpm at idle. I believed that my TPS needs adjusment, but does my alternator failing? My alt and battery are recently been changed.
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Old Nov 10, 2008 | 11:35 PM
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From: atlanta ga
this is common. the electrical load makes the alternator have to do more work. this in turn puts more resistance in the alternator making it harder to turn.
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Old Nov 11, 2008 | 12:01 AM
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fc3s
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From: bay area
Sorry, I keep trying to search this every few weeks but I don't really know what to search..

My car's idle bounces up and down after my car is warm and I've been driving for a while. When I come to stops and brake with my clutch in, the car gets low enough to make my lights dim really badly.

The biggest problem is when I turn my steering wheel, it get's really bouncy and almost dies, when I'm moving and making a turn on a street where the corner is really sharp, I have the clutch in and about half way through the turn my car dies..


Could this also be because the grounds are bad or maybe a dirty fuel socket?
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Old Nov 11, 2008 | 02:29 AM
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Depends. . . fuel sock by the way. . .

Does the idle bounce when sitting still and activating the power steering? Or only while moving?


The dying around turns would indicate a probable clogged fuel sock (located in fuel tank attached to the fuel pump). . . as for the erratic idle when warm. . .I don't know, could be many things.
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Old Nov 11, 2008 | 10:25 AM
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HAILERS
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From: FORT WORTH, TEXAS,USA
Originally Posted by galaxy convoy
Ok now my idle is soo low during i turned on my lights. When i turn on my lights or applied my brakes my rpm goes down during idle, i step on the gas to reach it to 2500rpm and let it go to idle then my rpm wents down to around 300rpm. But when i turned off my lights the rpm still low but when i rev it to 2500rpm then let it go, my rpm shoots down to a nice 900-1000rpm at idle. I believed that my TPS needs adjusment, but does my alternator failing? My alt and battery are recently been changed.

The BAC plug isn't connected. Or if it is, one of the contacts inside the elect plug is *pushed back* not making contact. OR the BAC transistor inside the ECU is burnt out from faulty wiring at the BAC plug.

900rpm is Rather high for an idle. Must be trying to cover up a fault with it. Ain't a TPS problem.
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Old Nov 11, 2008 | 11:52 AM
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From: bay area
Originally Posted by DavidHolmesIII
Depends. . . fuel sock by the way. . .

Does the idle bounce when sitting still and activating the power steering? Or only while moving?


The dying around turns would indicate a probable clogged fuel sock (located in fuel tank attached to the fuel pump). . . as for the erratic idle when warm. . .I don't know, could be many things.
The idle will bounce when sitting still also when it's fully warm.
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Old Nov 11, 2008 | 12:48 PM
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From: Old-Town BrightTown, CO
Well. . . try warming it up and unplugging the BAC plug. If you notice no change in the idle you will know its BAC related. Does it still start up normally? In other words. . . does it do the normal rev to 3000 and hold for 30 seconds before dropping to 1500 for a while before dropping to a final 750ish ?
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Old Nov 11, 2008 | 01:30 PM
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From: Rohnert Park CA
Originally Posted by galaxy convoy
then let it go, my rpm shoots down to a nice 900-1000rpm at idle.
idle should be 700-750 not 900-1000
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Old Nov 11, 2008 | 01:32 PM
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From: bay area
Originally Posted by DavidHolmesIII
Well. . . try warming it up and unplugging the BAC plug. If you notice no change in the idle you will know its BAC related. Does it still start up normally? In other words. . . does it do the normal rev to 3000 and hold for 30 seconds before dropping to 1500 for a while before dropping to a final 750ish ?
It.. Does start up, out of the 1.5 years I had the car, I've only had two troubles starting the car up. One was when it was a real cold morning, took me two cranks to get it started. The other was recently when I got my car back from Rick's Rotary, it seems one of the employees moved it out front to the pick up area without letting it warm up (lol) and he gave it a bit of gas to start it up.

My car DOES rev up to 3000 sometimes.. Sometimes it revs up to only about 1.5k-2k.

And it doesn't take mines 30 seconds, more like 8 - 10 seconds till it drops to 1500-1200 for about 1 minute, and then to about 850.
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Old Nov 11, 2008 | 01:42 PM
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From: Rohnert Park CA
Originally Posted by HeyITZthatFC
My car DOES rev up to 3000 sometimes.. Sometimes it revs up to only about 1.5k-2k.

And it doesn't take mines 30 seconds, more like 8 - 10 seconds till it drops to 1500-1200 for about 1 minute, and then to about 850.
If you start the car with the shifter in the neutral position (and the clutch in) it will rev to 3000 on cold start, but if you start the car in gear (with the clutch held in of course) then it will only rev to around 1500 on cold start.

It should then drop to 700-750 over the next 5 or so minutes as it warms up. The faster it warms up, the quicker it will drop.
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Old Nov 11, 2008 | 02:11 PM
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fc3s
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From: bay area
Originally Posted by Icemark
If you start the car with the shifter in the neutral position (and the clutch in) it will rev to 3000 on cold start, but if you start the car in gear (with the clutch held in of course) then it will only rev to around 1500 on cold start.

It should then drop to 700-750 over the next 5 or so minutes as it warms up. The faster it warms up, the quicker it will drop.
Hmm, I practically always turn my car on with the clutch in and on neutral.. Is there any cases where it does what my car does? Maybe I'll show a video of it if I can catch it in the act.

I really don't know what the problem could be when it does this, will the engine rev to 3k when it's a little warmed up? My memory is jogging me right now so I can't remember if I ever cold started my car and it did this..
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Old Nov 11, 2008 | 10:25 PM
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From: washington
Originally Posted by HAILERS
The BAC plug isn't connected. Or if it is, one of the contacts inside the elect plug is *pushed back* not making contact. OR the BAC transistor inside the ECU is burnt out from faulty wiring at the BAC plug.

900rpm is Rather high for an idle. Must be trying to cover up a fault with it. Ain't a TPS problem.
Ok Ill try to check my BAC

Originally Posted by Icemark
If you start the car with the shifter in the neutral position (and the clutch in) it will rev to 3000 on cold start, but if you start the car in gear (with the clutch held in of course) then it will only rev to around 1500 on cold start.

It should then drop to 700-750 over the next 5 or so minutes as it warms up. The faster it warms up, the quicker it will drop.
My car rev to 2000 on cold start clutch in and in neutral, is that bad?
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