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Low idle when cold

 
Old 03-10-2010, 11:22 AM
  #16  
Cosmo Kramer
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I have a local guy here with a Blinkr so I may give it a try, I just have the MAF set at the base value right now. Cold idle right now the wideband shows around 13-1. Drove it to work today and it is good.
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Old 03-12-2010, 04:13 PM
  #17  
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It's back! I started the car yesterday aft and it idles really slow, didn't stall but was around 500 rpm. I quick pulled out a jumper and disabled the ISV and it went lower, so the ISV is working. This one has me puzzled, something intermittent and those problems are always the worst.
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Old 03-12-2010, 04:58 PM
  #18  
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Did you also test the throttle position switch?

Dan
'91 928GT S/C 475hp/460lb.ft
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Old 03-12-2010, 08:33 PM
  #19  
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It could be that your idle switch is working intermittently, your idle may be set when it is not working and when it does work the idle is too low. If you adjust the idle with th diagnostic port jumped does it stall, that is the only way to set your base line it disconnects ICV valve and lets the engine idle where it should be. Test at the LH to see if it is closing and while your at it check the Wot switch, it's easy to get it out of adjustment.
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Old 03-14-2010, 04:27 PM
  #20  
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Tested the idle and WOT switches. Both are operational, but are showing around 30 ohms resistance when closed, car cold (I thought it should show 0). The WOT switch doesn't close until the pedal is right to the floor, again I thought is was supposed to close at about 2/3 - 3/4 throttle.
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Old 03-14-2010, 04:44 PM
  #21  
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Hi Ted, just copied this thread( r&r intake again!!) should help you.
https://rennlist.com/forums/928-foru...questions.html
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Old 03-14-2010, 06:01 PM
  #22  
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Did you check your meter does it zero out when shorted?
I found a ton of oil in my switch on the Euro it should be less then 10 Ohm's.
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Old 03-21-2010, 08:51 PM
  #23  
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Update: I tested the switch at the connection under the hood and it worked perfectly, and the plug connection there was loose so I fixed it. I also pulled the plugs at the LH and EZF and discovered that I had bent the connectors inside while testing. Straightened them up and the problem seems to have disappeared.
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Old 10-08-2010, 10:50 AM
  #24  
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Gonna resurrect my thread here because my haunting problem is back. It was probably always there in the summer but now the outside temperature is lower it is more noticeable.

Car is idling low when cold and fine once warmed up. Today was interesting, about 8 Celsius out and started the car in the garage this morning to take it to work. Idle was noticeably low but not on the verge of stalling out or surging, I would say it was 400 - 500 rpm. Left it running to warm up while I moved a car out of the driveway. Was standing beside the car after it had idled for about 4 min and it was like someone flipped a switch, it went to perfect cold fast idle all by itself. I have noticed this before in the past, low idle while backing out of the driveway then all of a sudden perfect cold idle. There have also been times when I get a perfect cold idle at startup but probably only 20-30% of the time. Obviously something intermittently electrical, but not sure what.

In the spring I was working on this issue and it is not the ISV, I disabled it while it was idling low/cold with a jumper on the diagnostic terminal and the idle went even lower. I also bench tested the ISV when I refreshed the intake and it was working perfect no sticking at all.

I have tested the temp 2 at the LH and the EZF connectors and it always shows in the proper range, but is it possible that it could have an intermittent fault? Does anyone know if there any other sensors that could cause a change in mixture or timing and cause a low idle?
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