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Idling issues just started...
Searched but haven't come up with any definite conclusions on what to look for.
When cold engine (air temp ~32F), the car idles at 400rpm and often stalls if the gas is let off. Car warms up after 2 minutes and car idles at 1050rpm and never threatens to fall below that. There is little fluctuation in the idling, very little pulsing. It just idles really really low. I've messed with the idle adjustment procedure per Clarks and no matter if it's set to 700rpm, or 1200rpm, the car idles at 400 when cold until a few minutes pass. New vacuum lines this autumn and no leaks as far as I can tell. New O2 sensor last spring. DME temp sensor is a few months old. Any ideas? |
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12-30-2008, 05:32 PM
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Greasy Member
Join Date: Mar 2006
Location: Indiana
Posts: 1,457
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First off, what oil are you running?
Second, when the idle is low is it rough? Like it is missing at all? If you can keep the car idling, try unplugging each injector connector and see if the idle is unchanged when one of them is disconnected. Could be a lazy injector, could be a little water in the fuel icing the injector. Hope it helps! -Nick
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Owner: Bennington Motorsports www.benms.com Sponsor for Midwest Region 944-SPEC racing series -When was your timing belt changed or tensioned?? -Yes, I'm the crazy man that will loan out my 9201. Just PM me, I will add you to the list and get it out ASAP. |
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12-30-2008, 05:57 PM
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Running 20W50 now only because I was having some oil pressure issues when warm. (Search my previous posts for info.) I have 4.5 bars on cold, and 2 bars on warm with the thicker oil. Car cranks at a normal speed and have no issues with the thicker oil. I wouldn't first attribute the idle issues with the oil.
It's not sputtering, stuttering, or missing, I don't believe. It's really low which makes the headlights dim slightly as if the car's about to stall. Then, it'll bounce back to 425/450 and be okay for a second only to nearly stall again. The idle sounds solid, just really really low. I'll attempt to test the injectors tomorrow. |
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12-30-2008, 06:42 PM
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Join Date: Jan 2008
Posts: 71
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May be the AFM.
Messed around with all of the half measures you listed....and it was ultimately a bad AFM.
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12-30-2008, 06:58 PM
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I've taken apart the AFM and made sure the potentiometer was operating perfectly. There are no hesitations in resistance/current as the door to the meter is opened. It's a smooth line all the way from idle to WOT.
What's the relationship between the idle screw and the throttle positioning sensor? I've seen some posts here relating the two. The TPS is verified to operate perfectly in all three settings, also, clicking the switches inside at the right positions. Are the two related? |
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12-30-2008, 07:43 PM
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1986 Porsche 944 2.5L N/A
