 Backwards idle RPM, On startup the RPMs are below 800, and after... |
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| Jamie |
 Sep 19 2018, 09:26 AM
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#1
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Senior Member  Group: Members Posts: 1,102 Joined: 13-October 04 From: Georgetown,KY Member No.: 2,939 Region Association: South East States 
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....reaching running temp the idle varies between 1400~1500 RPM. That's backwards from what it should be? I have replaced several hoses, checked all areas I could with spritzes of carb cleaner without any effect, so what other components regulate RPM at temperature? I'm no mechanic with the finer details of the D-jet system on my 1.7L motor.
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| 914sgofast2 |
Sep 19 2018, 10:27 AM
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#2
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Senior Member Group: Members Posts: 717 Joined: 10-May 13 From: El Dorado Hills, CA Member No.: 15,855 Region Association: None |
The AAR (auxiliary air regulator) is probably stuck in the open position. Needs to be cleaned by soaking in carb cleaner or replaced if the heating element has gone bad and no longer closes the valve.
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| Jamie |
Sep 19 2018, 08:24 PM
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#3
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Senior Member Group: Members Posts: 1,102 Joined: 13-October 04 From: Georgetown,KY Member No.: 2,939 Region Association: South East States
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QUOTE(914sgofast2 @ Sep 19 2018, 08:27 AM)  The AAR (auxiliary air regulator) is probably stuck in the open position. Needs to be cleaned by soaking in carb cleaner or replaced if the heating element has gone bad and no longer closes the valve. Now I'll just have to discover where the AAR is located and what it looks like! (IMG:style_emoticons/default/confused24.gif) |
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| era vulgaris |
Sep 20 2018, 07:48 AM
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#4
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J is for Genius Group: Members Posts: 983 Joined: 10-November 13 From: Raleigh, NC Member No.: 16,629 Region Association: South East States |
QUOTE(Jamie @ Sep 19 2018, 10:24 PM) Now I'll just have to discover where the AAR is located and what it looks like! (IMG:style_emoticons/default/confused24.gif) This is it. It'll be on the driver's side on top of the engine, just in front of the intake runners. Remove it from the car. Soak in carb cleaner, WD40, etc overnight. If you have a bench DC power supply, you can test it by putting 12VDC on the wire lead and ground on the body of the AAR. With power applied, it will heat up and slowly close until you can't blow air through it. Attached image(s) 
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| ndfrigi |
Sep 20 2018, 11:01 AM
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#5
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Advanced Member Group: Members Posts: 2,965 Joined: 21-August 11 From: Orange County Member No.: 13,474 Region Association: Southern California
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not against 914sgofast2. I think it is the other way around. Maybe your AAR is stuck closed, during cold start the engine will run in lower rpm since no air coming In from AAR. and when the engine is on the proper temperature, rpm will go up. Maybe try to adjust ur idle between 800 and 900 when engine is already on the proper temp. But your cold start may need some acceleration since idle will be too low and If AAR does not get some air.
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| pete000 |
Sep 20 2018, 11:06 AM
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#6
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Senior Member Group: Members Posts: 1,887 Joined: 23-August 10 From: Bradenton Florida Member No.: 12,094 Region Association: South East States |
Engine wants more air at cold start up. This is the job of the AAR. So if you adjust your idle back to 950-1000 when warm your car will probably not idle when cold.
Air leaks are sometimes hard to find. Start by checking the AAR and work your way through the entire system Worn throttle bodies can cause issues as well and are often overlooked. I spent a long time with my L-Jet air leaks to make it happy... |
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| TheCabinetmaker |
Sep 20 2018, 05:25 PM
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#7
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I drive my car everyday Group: Members Posts: 8,336 Joined: 8-May 03 From: Tulsa, Ok. Member No.: 666 |
QUOTE(ndfrigi @ Sep 20 2018, 12:01 PM) not against 914sgofast2. I think it is the other way around. Maybe your AAR is stuck closed, during cold start the engine will run in lower rpm since no air coming In from AAR. and when the engine is on the proper temperature, rpm will go up. Maybe try to adjust ur idle between 800 and 900 when engine is already on the proper temp. But your cold start may need some acceleration since idle will be too low and If AAR does not get some air. He had it right, and Pete00 explained it. |
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