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Registered
Join Date: Jan 2006
Location: New England
Posts: 215
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'70E part-load miss -- plug wires?
The car starts and idles well, and responds well to generous throttle, but has definite and very consistent issues with, say, mild acceleration off idle and into mid-range rpm in normal driving. I've been wrestling with this problem as time permits, trying to go gently into step-by-step diagnosis of what I perceive is an MFI problem. Dwell, timing, advance, valve adj., etc., are all good.
It's suddenly dawned on me that it might be plug wires, which have not been replaced in several years, if ever in its 48,000 miles. I realize that there is no substitute for actual diagnostic technique--I'm just doing a little sanity check. Does this sound, possibly, like the symptom of aging and failing wires, or am I dreaming? Last edited by JohnKo; 05-08-2007 at 10:03 AM.. |
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05-08-2007, 09:52 AM
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Registered
Join Date: Jan 2004
Location: Sydney
Posts: 327
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John,
As well as the electrics maybe you should consider correct fuel pressure from the gas tank to the MFI pump. I have had my car for three years now and my mechanic has only just now found the last piece of the puzzle. Starting in the gas tank,empty it and check for blockages in the gauze filter in the tank.If in doubt,get a new one. From the tank to the fuel filter,make sure the fuel lines are not kinked or deteriorated.This is also a safety issue. How recent is the fuel filter ? Is your fuel clean at your local gas station ? Are you using the right octane gas?with or without an octane booster? Only then consider adjustments of the MFI pump. After all these items checked,plus many more,my car is just superb to drive !! Cheers, Dennis. 
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The 914-6 from my 'Lotto'garage has finally arrived. 1971 911S 2.2. 1975 Carrera Targa (ROW) - missed. One of us is fast becoming a valuable antique. Last edited by gulf908; 05-09-2007 at 03:02 AM.. |
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05-09-2007, 02:59 AM
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Moderator
Join Date: Dec 2001
Posts: 9,569
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John, it sounds like a great opportunity to run through Check Measure Adjust.
Any competent Porsche driver tracks faster if brakes come smoothly-- Air-filter compression-loss plugs dwell timing fuel-pressure injectors belt correlation smog.
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'66 911 #304065 Irischgruen ‘96 993 Carrera 2 Polarsilber '81 R65 Ex-'71 911 PCA C-Stock Club Racer #806 (Sold 5/15/13) Ex-'88 Carrera (Sold 3/29/02) Ex-'91 Carrera 2 Cabriolet (Sold 8/20/04) Ex-'89 944 Turbo S (Sold 8/21/20) |
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05-09-2007, 06:35 AM
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Registered
Join Date: Jan 2006
Location: New England
Posts: 215
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Thank you both. Check-Measure-Adjust is definitely the main plan. And, Dennis, your fuel system recommendations sound good too. I have a new filter ready to install, etc., etc. I just got a little too excited thinking about the possibility of plug wires being a simple fix.
Thanks again. John |
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05-09-2007, 08:25 AM
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