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-   -   Problem with 'points' or MFI? (http://forums.pelicanparts.com/porsche-911-technical-forum/30219-problem-points-mfi.html)

TWJ 05-01-2000 10:33 AM

Problem with 'points' or MFI?
 
Having read through a number of old threads I believe I have narrowed the problem that raised it's ungly head this past weekend to one of two issues. The problem, which occured very suddenly, is that my '72 911T (with engine rebuilt to 'S'specs) first began to idle irradically (up and down slightly) then began to pop (misfire?) occassionally, then both got dramatically worse quite quickly. That is the idle would drop suddenly with lots of popping and it would pop some at any RPM level. All the time the tachometer seemed to have a mind of its own, sometimes reading correctly and others times on a wild ride. Is this an indication of a problem with the points (I think) or potentially with the MFI (running to rich)? Having rebuilt and fine-tuned several VW's 25-30 years ago nothing on this engine looks to unfamilier or intimidating to work on (maybe the MFI). As always the help is greatly appreciated!!!

Early_S_Man 05-01-2000 10:54 AM

Without much doubt, it it is points or distributor-related ... as nothing in the MFI could make your tach misbehave, and it would take two simultaneous failures to have mixture problems AND tach problems ... both at once!

I would recommend turning the engine over manually to Z1 mark on Cyl. 1, then pull out the complete distributor as a unit for further work and diagnosis, because they aren't much fun to work on in the car!

I suspect one of three possible problems:

1. Bad point set needing replacement

2. Loose point plate inside distributor

3. Broken/loose ground wire to point plate inside distributor ... the bare wire spot welded to the plate has been known to break right at the spot weld!

All three are easy fixes, but maybe not so easy to recognize to the inexperienced ... so let us know what you find inside the distributor!!!

------------------
Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 05-01-2000).]

TWJ 05-01-2000 11:24 AM

Thanks Warren!
I will post my findings.

TWJ 05-06-2000 10:36 AM

Upon examination the points were barely opening, dwell angle way off. Removed points, cleaned, reinstalled and set to spec gap. She runs like a champ!!! Seems like I found 50 hp.

Thanks for you help Warren!


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