 OT (somewhat) 911S 2.2l Motor maladies, Steady Throttle popping issue |
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| Cupomeat |
 Oct 22 2010, 02:16 PM
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missing my NY 914 in VA  Group: Members Posts: 1,338 Joined: 26-November 07 From: Oakton VA Member No.: 8,376 Region Association: MidAtlantic Region  |
My Dad's 911S has an issue with intake popping while normal driving.
BACKGROUND; Engine fully rebuilt (within 1.5k miles) and valves adjusted about 2 weeks ago. Engine was an MFI engine converted to PMOs before we bought the car. (someday I dream to go back to MFI.) SYMPTOM: Prior to the valve adjust a sporadic 'Popping" was coming from the intake as a small backfire on a regular basis. After the valve adjust (first since rebuild), it runs better but still pops. When I go up there, I am going to check the rotor and dist cap, but anything else to check? Sadly, the motor does not run nearly as strongly after the rebuild as it did before the rebuild (crazy, I know). The top end, just isn't there now like it was before. I don't get the needed time to spend with the car, tinkering, as I'd like to see why. But, back to the popping, It seems to happen mostly while cruising at part throttle. My logic says that it is ignition and that a spark plug (or carbon build up?) is firing while the intake valve is open. Does this makes sense? David asked me if they carbs had been rebuilt, and it has been years since they have, but there are no flat spots or stumbles while driving. Thanks |
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| sixnotfour |
Oct 24 2010, 07:25 PM
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914 Wizard Group: Members Posts: 10,906 Joined: 12-September 04 From: Life Elevated..planet UT. Member No.: 2,744 Region Association: Rocky Mountains 
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if you went from 2.0 to 2.2 it needs rejetting
http://members.rennlist.com/webercarbs/Web...et_Settings.htm |
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| Cupomeat |
Oct 24 2010, 08:25 PM
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missing my NY 914 in VA Group: Members Posts: 1,338 Joined: 26-November 07 From: Oakton VA Member No.: 8,376 Region Association: MidAtlantic Region |
QUOTE(sixnotfour @ Oct 24 2010, 09:25 PM)  if you went from 2.0 to 2.2 it needs rejetting http://members.rennlist.com/webercarbs/Web...et_Settings.htm This is a good reference, but it shows that the 2.0s and the 2.2s have the same initial setting on all parts. |
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Posts in this topic
Cupomeat OT (somewhat) 911S 2.2l Motor maladies Oct 22 2010, 02:16 PM
Eric_Shea Clean the idle jets and richen it up. Oct 22 2010, 02:21 PM
Cupomeat
Clean the idle jets and richen it up.
Ok, Great... Oct 22 2010, 02:30 PM
SLITS
Clean the idle jets and richen it up.
This from... Oct 22 2010, 02:35 PM ArtechnikA
SYMPTOM: Prior to the valve adjust a sporadic ... Oct 22 2010, 02:39 PM Cupomeat
SYMPTOM: Prior to the valve adjust a sporadic ... Oct 22 2010, 03:00 PM ArtechnikA
So, in theory, what is causing the popping? How i... Oct 22 2010, 05:40 PM mskala Depending on what you mean by rebuilt, things coul... Oct 22 2010, 06:09 PM Cupomeat
Depending on what you mean by rebuilt, things cou... Oct 24 2010, 06:50 PM Cupomeat
So, in theory, what is causing the popping? How ... Oct 24 2010, 06:46 PM Eric_Shea
I speak from "experience". I also thi... Oct 22 2010, 03:20 PM Eric_Shea
Usually a lean condition. Oct 22 2010, 03:22 PM Rav914 Who rebuilt the motor?
Hopefully not Motor Meiste... Oct 23 2010, 06:59 AM 9146986 Read my carb tuning thread, it'll help. Oct 23 2010, 02:49 PM mskala This is a good reference, but it shows that the 2.... Oct 25 2010, 09:47 AM |
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