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Discussion Starter #1
Figured out my really rich issue with my 1987 alfa spider that a bought awhile back and just got on the road the last 2 days. The car had a stuck open injector causing the car to run rich and I replace the faulty injector and the car runs well now with good power however my idle now goes up and down and wanted to know where to start. My o2 sensor is new and I believe my MAF to be in good working shape and the car has new wires, plugs, rotor and cap. I checked all my hose connections and everything seems to be tight. Would the idkle control valve do this or do you guys think that I have an air leak somewhere/ The car runs well throughout the rpm range just has an idle up and down issue. Any help would be appriciated.
 

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But Mad North-Northwest
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It's not the idle valve. If I had to guess I'd say a bad or misadjusted throttle position switch. But I'd suggest going through the whole L-Jetronic troubleshooting guide:

 

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Discussion Starter #3
If my car had a maladjusted TPS would it run well at all rpms except for idle?
 

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Yes.

The AAV (Aux Air Valve) is supposed to open when cold & close when warm. This increases the cold idle speed and returns it to normal when it warms up. When they get old the AAV fails - usually in a partially open position. I don't know if they are available new and used ones are a crap shoot. I've got a bin of failed ones. The one in our Spider still works. Cold idle is about 1300 - 1400 rpm, warm idle is 900 - 1000 rpm. To look inside an AAV see: Inside an AAV

Most likely cause for the irregular idle speed is a misadjusted TPS (Throttle Position Switch - not Sensor). Properly adjusted, the TPS will tell the computer the throttle is at idle, not at idle or wide open. At idle the computer follows its pre-programmed idle mixture map, at not idle it uses the input from the O2 sensor to adjust the mixture, at wide open is ignores the O2 sensor and supplies max fuel. Thus, if the TPS is misadjusted, the computer is probably trying to continually adjust the mixture at idle. It does this by varying the mixture from slightly lean to slightly rich - back & forth, back & forth with the average being correct. But at idle this is inexact.

Properly adjusted the throttle plate (aka butterfly) is barely open - just enough to not slam the throttle closed - and the desired idle speed is adjusted with the Idle Speed Adjuster. Inside the Idle Adjuster is a fat O-ring. Tightening the adjuster squeezes the O-ring to make its ID smaller, loosening the adjuster allows it to relax and the ID increases. But as it gets old the O-ring gets hard and doesn't allow this adjustment. Simple solution is to replace the O-ring.

With a supple O-ring in the adjuster, I close the throttle by turning the stop screw CCW then turn it in until the idle speed increases by 25 - 50 rpm. Now use the idle adjuster to set the desired idle speed (900 - 1000 rpm). Now you can adjust the TPS - its mounting holes are slightly oblong to allow it to move. It should 'click' when the throttle is moved a couple of degrees off the stop. This is all outlined in the L-jet Diagnosis page.
 

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Discussion Starter #5
Thank you both for your help. This car has sat for who knows how long with neglected owners,.
 

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Discussion Starter #6
Well it was the TPS. Someone had it all the way advanced. I believe that I have it dialed in correctly and even fine tuned the used AFM that I installed. Thank you alfa community for all the help.
 
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