Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
> Backwards idle RPM, On startup the RPMs are below 800, and after...
Jamie
post Sep 19 2018, 09:26 AM
Post #1


Senior Member
***

Group: Members
Posts: 1,025
Joined: 13-October 04
From: Georgetown,KY
Member No.: 2,939
Region Association: South East States



....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.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
914sgofast2
post Sep 19 2018, 10:27 AM
Post #2


Senior Member
***

Group: Members
Posts: 613
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.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Jamie
post Sep 19 2018, 08:24 PM
Post #3


Senior Member
***

Group: Members
Posts: 1,025
Joined: 13-October 04
From: Georgetown,KY
Member No.: 2,939
Region Association: South East States



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)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
era vulgaris
post Sep 20 2018, 07:48 AM
Post #4


J is for Genius
***

Group: Members
Posts: 982
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)
Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
ndfrigi
post Sep 20 2018, 11:01 AM
Post #5


Advanced Member
****

Group: Members
Posts: 2,928
Joined: 21-August 11
From: Orange County
Member No.: 13,474
Region Association: Southern California



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.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
pete000
post Sep 20 2018, 11:06 AM
Post #6


Senior Member
***

Group: Members
Posts: 1,885
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...
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
TheCabinetmaker
post Sep 20 2018, 05:25 PM
Post #7


I drive my car everyday
*****

Group: Members
Posts: 8,300
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.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 28th April 2024 - 02:50 PM