1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

81 - 12a Problem

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Old 11-26-03, 04:25 PM
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81 - 12a Problem

I have a strange problem with my car and perhaps sombody else has had a similar problem and can help. Here is goes:

The engine will not stay at a constant RPM. If in neutral and I rev it up to 2,000 RPM and hold it, the RPM will wonder around 2,000 and will not stay at 2,000 RPM. Also, when driving down the road in the first few gears, when around 2,000 RPM, you can feel the car lose power and gain it (you can feel it chaning RPM). If I set the RPM to 2,000 using the choke, then the car will idle fine and stays at a constant 2,000 RPM. Also, at higher RPM (>3500) and at idle, the RPM is steady.

Anybody know what my problem might be?

Thanks in advance for any help!
Old 11-26-03, 05:40 PM
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Vacuum leaks. That's where I'd start.
Old 11-26-03, 11:59 PM
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You probably need a new BAC valve which is located on the upper dynamic chamber on you're intake manifold. You might also need a new Throttle Position Sensor.
Old 11-27-03, 05:49 AM
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Driven a turbo FB lately?

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**** that could be anything, id say fuel, or maybe igntion
Old 11-27-03, 05:50 AM
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Driven a turbo FB lately?

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Originally posted by theweasel
You probably need a new BAC valve which is located on the upper dynamic chamber on you're intake manifold. You might also need a new Throttle Position Sensor.
so Se motors are available in 81's? thats news to me
Old 11-27-03, 01:44 PM
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Sorry mike, brain fart. Came across good information, didnt think about the vehicle. My bad.
Old 11-27-03, 10:15 PM
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hehe i laugh
Old 11-27-03, 11:04 PM
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There is a throttle sensor on the nikki carbs....
Little black plastic piece of crap on the front passenger side... Never tuned mine like they say you should after tweaking the mixture... perhaps that's my problem?

lindr6, I had a similar problem when I first got mine on the road...
for the most part I'm not exactly sure what fixed it for me...
We believed the problem to be vacuum or mixture related and kept cleaning the carb... The problem seems to have gone away...
Just my 2 cents
Good luck
Old 11-28-03, 04:28 PM
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im no expert but could it be a problem with the transition circuit from low to main? that would explain why it is steady with the choke and stumbles when you use the gas pedal...
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