Hello - I am working on a 3.0L 1980 Porsche 911 with MSII for a friend - it starts easily but the pedal must be pushed to keep it running - if I adjust the Throttle Body screw to get a higher idle speed it will run great when cold but the idle when warm will be too high. Have searched for vacuum leaks (3 different people have searched) and I even adjusted the throttle lever adjusting screw to allow the butterfly to close farther. The VE table is set to default - fairly lean but with no backfires.
1. Should I adjust the throttle level to fully closed and try that? any negatives to having the butterfly closed completely at idle? Will it even idle closed?
2. Any other things to cause this (other than vacuum or VE) ?
Thx -
Normal Idle when cold - High Idle when warm
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0). For tuning/troubleshooting questions, please attached a datalog and your MSQ file to your post.
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
The full forum rules are here: Forum Rules, be sure to read them all regularly.
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Matt Cramer
- Super Squirter
- Posts: 2951
- Joined: Sat Jul 03, 2004 11:35 am
Re: Normal Idle when cold - High Idle when warm
What are you using for an IAC valve?
Re: Normal Idle when cold - High Idle when warm
An IAC i not typically used on the Porsche 911. There's not one on my '74 which I installed 3 years ago (and have no problem with idle) and there's not one on the 80 911 which I'm working on. Same for the TPS - the software uses the MAP as a substitute for the TPS after a study showed the MAP follows RPM very closely.
Anyway - to answer your question - there is no IAC. Perhaps if there were one this problem could be fixed easier!
Thx
Anyway - to answer your question - there is no IAC. Perhaps if there were one this problem could be fixed easier!
Thx
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Matt Cramer
- Super Squirter
- Posts: 2951
- Joined: Sat Jul 03, 2004 11:35 am
Re: Normal Idle when cold - High Idle when warm
Yes, without an IAC you'll often have the engine behave like this. A lot of D-Jetronic systems used a similar device called an auxiliary air valve that works without a connection to the ECU.
Re: Normal Idle when cold - High Idle when warm
Yes, the 911s re-use the AAR that was originally used on the factory installed CSI system. It's been checked and was found to be working - it's basically a controlled vacuum leak. It starts out open and as the engine warms it closes.
Thx for trying -
Larry
Thx for trying -
Larry