|
|
|
|
| Author |
|
|
Registered
Join Date: Aug 2009
Posts: 5
|
81 sc rpm surge
Starts up great but after a few seconds RPM surges from 4/500 to appx. 1500 and then drop back to 4/500. Will die when pull up to traffic light. Help!
|
||
08-06-2009, 08:25 AM
|
|
|
Registered
Join Date: Jun 2009
Location: Manhattan Beach, California. Factory Delivery-Original owner-Retired engineer
Posts: 5,238
|
From personal experience,
this is just one of the many possibilities. Check these vaccum lines from the back of the air meter to the fuel pressure regulators. If you remove your oil filler cap, any change? Also your idle rpm's should be around 850-950. Is your idle set correctly? Good luck, Gerry 
Last edited by 86 911 Targa; 08-06-2009 at 08:41 AM.. |
||
|
08-06-2009, 08:37 AM
|
|
|
Registered
Join Date: Aug 2004
Location: San Antonio, TX
Posts: 1,814
|
It should idle higher than 400-500. It should be more like 850+/-50 if I remember correctly. There is a large spring and flat head screw assembly front and center on top of the CIS. You can turn that to raise the idle.
I had a similar problem when I drove up to high altitude.
__________________
Paul 1980 911SC Targa - Sold 1972 914 - Sold |
||
|
08-06-2009, 08:40 AM
|
|
|
Registered
Join Date: Aug 2009
Posts: 5
|
Gerry/Brother
Thx for the quick reply-I'll investigste. |
||
|
08-06-2009, 08:59 AM
|
|
|
Registered
|
as an aside, I have no way to turn that screw with a screw driver with everything installed, so you just need to use your fingers.
__________________
T-Shirt wearing, sticker toting, SCWDP registered member  Why when you misplace something is it always found the last place you look? Because you stop looking after you've found it  '83 911sc ROW Targa '84 BMW 320i (what did I get myself into?!) |
||
|
08-06-2009, 09:34 AM
|
|
|
Designer King
Join Date: Mar 2004
Location: Toronto, ON Canada
Posts: 5,499
|
If it is a rhythmic up and down fluctuation of the speed, it is usually a too rich mixture.
If it holds a speed, then drops, comes back up, holds and repeats, then it is often a too lean mixture. There are various reasons for this. Has this symptom suddenly appeared?
__________________
Paul Yellow 77 Sunroof Coupe/cork interior; 3.2L SS '80 engine/10.3:1/No O2; Carrera Tensioners; 11 Blade Fan; Turbo tie rods; Bilstein B6; 28 tube Cooler; SSI, Dansk; MSD/Blaster; 16x7" Fuchs/205/50 Firestone Firehawk Indy 500s; PCA/UCR, MID9 Never leave well enough alone |
||
|
08-06-2009, 11:25 AM
|
|
|
