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Smart quod bastardus
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high idle when cold
I recently started notciing that my 1979 930 turbo remains on a high idle now that the weather has gotten cold in Michigan.
I start the car and it never seems to come below 1200-1500rpm even when left to idle for over 10 minutes. -----After driving the car under load for 20 minutes or so the idle will still remain at 1200rpm or more when I stop at a light. The weather here is now in the 40 degree F range and I never had the problem in the summertime. ----Anyone know what is the cause and what I should check? The car is completely stock and the summer idle was 900rpm according to the tach. |
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11-21-2006, 02:19 PM
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Join Date: Mar 2002
Posts: 3,563
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hmmm, a bit strange. My Carrera idles high on cold start for a minute or two, but then settles to 850rpm's or so. I don't know much about the CIS systems, but sounds to me like you have a dodgey WUR (Warm Up Reg)? Hopefully someone more CIS-savy would tune in here. Good luck!
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Merv '89 911 Turbo Cab Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition 
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11-21-2006, 02:24 PM
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AAR sounds like it lost power to close in its time frame or it is shot..
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Ben 89 944,85.5 944 914-6 2.4s GT tribute. 914-6werkshop.com |
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11-21-2006, 02:49 PM
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Join Date: Aug 2002
Location: OverlandPark KS (Kansas City)
Posts: 526
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AAR or the AAV. Both will cause issues. You can take off the AAR and apply 12 volts to the plug. The unit should start closing down in less than 5 minutes. If it doesn't then it is bad. The unit will then only close based on the heat of the motor reaching the unit instead of the unit heating on its own to close the door. There is a bi-metal strip that heats up and closes the door. This is what goes bad.
If this is not the problem the AAV is stuck and or bad. This aids in start up around the AAR when you hit the key. It runs on the same circuit of hoses just is a valve that opens while the car is cranking and first starts. This is a common issue as well. Always has been on the SCs. The factory fix was to smash the valve in a vice 5mm. LOL, I am serious.
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Stephen 94 3.6Turbo 6-speed AWD |
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11-22-2006, 06:00 AM
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My car with the weather drop is the same. I also run very cold to begin with so it really takes alot of time for the idle to come down.
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1986 blk 930 2000 expedition 2000 bmw 3 series convertable 1996 Silverton 312 sedan bridge |
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11-23-2006, 05:57 AM
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Join Date: Mar 2001
Location: Marysville Wa.
Posts: 22,536
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78/79 930s had an obnoxiously high cold idle anyway. (after restarting warm after sitting a short while also). using a AAR from an SC helps a lot. we used to do that at the dealer in the 70s. winter to summer temps can require some minor mixture and idle speed tweeks. have you tried just turning down the idle speed when it's hot and checking the CO?
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https://www.instagram.com/johnwalker8704 8009 103rd pl ne Marysville Wa 98270 206 637 4071 |
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11-23-2006, 10:30 AM
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Smart quod bastardus
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Alot of good ideas so far, thanks for the info.....keep it coming.
As I just got the car a few months ago, I have not tried tuning it or changing anything with the CIS or fuel system as it ran fine until the weather got cold. I checked iginition timing and it seems ok, but it appears I need to do a little removing of components now to check them all, which I was hoping to avoid. |
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11-27-2006, 09:34 AM
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Romel
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i have a similar or weird idle problem when the air/winter is cold (not the car). its a euro 3.3 930 turbo. its in a temp controlled garage, approx 72 degrees F all year. It'll start (3 cranks) and idle at 950 in the garage (it does not idle high). I'll drive outside the garage where the temp is about 55 or below degree F. within 1min of being out side the idle goes up to 1400 and stays there. It might go down after an hr or so driving. If its really cold it says high sometimes 1600. In the summer when the air is hot (about 68 degree F) it idles just fine. I checked and verified its not the AAR ( crimped off the hose which doesnt makes a difference). any ideas? Thank you
Last edited by labdag; 11-06-2019 at 05:49 PM.. |
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11-06-2019, 05:11 PM
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Join Date: Jul 2008
Location: Central Washington State
Posts: 4,422
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IF it's the AAR and not the AAV, pinch the hose closed directly after the AAR. If the rpm's drop, the AAR is stuck open too far. Remember that it gets it's power through the rear fuel pump relay, so four things are possible: the rear relay (and thus the rear fuel pump as well) is not working and no power is going to the AAR, the wires to the AAR are compromised somewhere and it's not getting power, the AAR internal heating element is toasted, or the internal components are gummed up and not moving.
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Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, B&B intercooler, stock 3LDZ. |
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11-07-2019, 05:08 AM
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Romel
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Hi Mark, thank you very much for your input. That was one of the first things i did. As it was idling high in the cold air, I pinched off the hose from the intercooler to the AAR. It made no difference. Idling was still high. I also undo the hose and looked inside the AAR and it was fully closed while the engine was running. could the AAV (instead of the AAR-which has a vacuum port) cause this issue?
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11-08-2019, 02:46 AM
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Herman the German
1986 Porsche 930 turbo 3.3 litre
Blues
