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Old 06-14-2007, 10:03 AM
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gdpedersen gdpedersen is offline
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L-Jet idle too fast

My 85 graduate has an idle problem I'm trying to resolve and I would appreciate any advise.

At start up when its cold, the idle is a nice, stable 900 rpm, but as it warms up the idle starts to creep up. When its fully warm it's turning about 1300 rpm. I've adjusted the set screw on the throttle body, but if I use that to set the warm idle, the cold idle is too slow.

The maunal shows another adjustment where a hose from the hard rubber intake sleeve connects to the plenum, but this doesn't seem to do anything. Maybe I haven't backed it off far enough yet? Is there something else I'm missing?

Thanks for any help!
Gene
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Old 06-14-2007, 10:08 AM
Greg Gordon Greg Gordon is offline
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May I humbly suggest you pay a visit to my site here: http://www.hiperformancestore.com/Ljetspider.htm

Three of the sharpest people on this board took an old GTV6/Milano article I wrote and adapted it to the Spider for just this situation.

Good Luck,
Greg
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Old 06-14-2007, 11:39 AM
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gdpedersen gdpedersen is offline
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Hey Greg.
Thanks for the great article. It's very clearly written and illustrated.

I read through most of it and I think I'll start with the "donut" in the idle speed adjustment in the plenum (then go through the complete procedure when time premits). That adjustment in my car was screwed all the way into the plenum. Is the donut just a standard O-ring I can get anywhere or is a special part I will need to order? Thanks again for your help.

Gene
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Old 06-14-2007, 12:10 PM
BlackAlfa BlackAlfa is offline
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Quote:
Originally Posted by gdpedersen View Post
At start up when its cold, the idle is a nice, stable 900 rpm, but as it warms up the idle starts to creep up. When its fully warm it's turning about 1300 rpm. I've adjusted the set screw on the throttle body, but if I use that to set the warm idle, the cold idle is too slow.
It sounds like a warming up idle management problem. The primary device for this is the Auxiliary Air Valve (AAV). Perhaps yours is frozen in one position (perhaps slightly open so your cold idle speed is not high enough and your warm idle adjustment at plenum was screwed all the way in in an attempt to lower the warm idle). This device should open at cold letting more air in and thus higher idle and then it should gradually close up to full close while the engine is warming up. There's a heating element inside (hence the electrical plug) to heat up the bimetal spring (or whatever). You might want to check and clean that. The set screw on the throttle is for the amount of air to get pass the throttle plate at idle. Without a air flow/pressure measuring device, just set it back to almost close but without binding at the throttle plate. You need to check the throttle position switch adjustment (to make sure you hear a click when throttle open) since you played with the throttle plate set screw.

Quote:
The maunal shows another adjustment where a hose from the hard rubber intake sleeve connects to the plenum, but this doesn't seem to do anything. Maybe I haven't backed it off far enough yet? Is there something else I'm missing?
This is where you set the warm idle speed and you need a good (special) rubber donut there.
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Old 06-14-2007, 02:09 PM
ghnl ghnl is online now
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Quote:
Originally Posted by gdpedersen View Post
Is the donut just a standard O-ring I can get anywhere or is a special part I will need to order?
I took the old O-ring with me to the hardware store and bought a few in various sizes that appeared close to the old one. Then I used the one that fit the best. So, nothing special. It might be best to buy the O-ring at a auto supply store - perhaps the material they are made from might be better suited for an automobile? But, so far so good.
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