|
|
|
|
| Author |
|
|
Registered
Join Date: Dec 2002
Location: Olympia WA
Posts: 68
|
80 3.0 cis surging missing
My 3.0 is surging when I start it cold (for about 30 seconds), and when its warm (after sitting for a few minutes.) Also misses at a constant speed ie. Any ideas? Ive replaced: cap, rotor, plugs, wires, coil, injectors. Messed with: timing, air/fuel, idle. What do you all think? Warm Up Regulator? Cold Start Valve?
Any help would be much appreciated. Last edited by 80sctarga; 12-08-2002 at 08:33 AM.. |
||
12-08-2002, 08:02 AM
|
|
|
Registered
Join Date: Mar 2002
Location: Miami
Posts: 599
|
I have a very similar problem with my 2.7L. On cold start my idle searches (surges) until car is completely warmed about 20 minutes or 190 degrees. Idle searching will begin to taper off then. I have replaced accumulator, fuel filter, thermo switch, fuel injectors, adjusted co.
__________________
1975 911 Carrera BLK/BLK |
||
|
12-08-2002, 08:13 AM
|
|
|
Recreational Mechanic
|
Have you tried unplugging the O2 sensor? This won't explain your cold start problem (O2 sensor does not function until warm), but has been known to cure warm idle "hunting". On K-Lambda CIS you do no harm by disconnecting...the O2 sensor system was an add-on auxillary system. Reset the mixture once disconnected.
Worth a try. Nick.
__________________
P Cars: 2022 Macan GTS / One empty garage space ---- Other cars: 2019 Golf R 6MT / 2021 F-250 Diesel / 2024 Toyota GR86 6MT ---- Gone: 1997 Spec Boxster Race Car, 2020 GT4, 2004 GT3, 2003 Carrera, 1982 911SC, 2005 Lotus Elise and lots of other non-Porsches PCA National DE Instructor #202106053 / PCA Club Racing / WRL Endurance Racing |
||
|
12-08-2002, 10:55 AM
|
|
|
Registered
Join Date: Dec 1999
Location: Novato, CA
Posts: 4,740
|
My 78 3.0 would surge on cold start if it was set too rich. Setting the mixture correctly seemed to help constant rpm surging too.
Cheers, Joe |
||
|
12-08-2002, 11:27 AM
|
|
|
Registered
Join Date: Sep 2000
Location: Shreveport, La.
Posts: 1,710
|
I had a similar problem with my 83 last year. Turned out to be intermittent relay (under pass seat) that operates the frequency valve.
__________________
Robert Stoll 83 911 SC 83 944 |
||
|
12-08-2002, 11:42 AM
|
|
|
Registered
Join Date: Dec 2002
Location: Olympia WA
Posts: 68
|
OK. got the "surging". (a little air fuel, alot timing, 1/2 turn on the idle.)
So what about the miss? Thanks guys! |
||
|
12-08-2002, 01:14 PM
|
|
|
|
Registered
Join Date: Dec 2002
Location: Olympia WA
Posts: 68
|
Sorry..........its doing it at a constant rpm. ie 2nd gear at 30 mph 3100 rpm you can really feel it.
Thanks again |
||
|
12-08-2002, 01:17 PM
|
|
911SC 3.0
