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Grady Clay Grady Clay is offline
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Join Date: Dec 2003
Location: Arapahoe County, Colorado, USA
Posts: 9,032
Dom,

The place to apply some lube (money) is to establish a baseline for all the things that affect the performance of the MFI. If your only complaint is slight misbehavior at part throttle and 3500 rpm, it may be right on the lean limit. That’s OK.

Your question about the CDI is a good one. The Bosch CDI is very good at getting sparkplugs to fire in potential fouling conditions; too cold plugs, too rich, light driving, cold weather, etc. This is because the system has a very short risetime of the spark.

It’s not as good as some later systems in getting a lean, low pressure mixture to consistently fire; light throttle, 3500 rpm. This results in the too common surge at 3500 and light throttle. The “fat” spark from a regular Kettering ignition system is actually better in these conditions.

The current generation of very powerful ignition systems have the best of both worlds; they can fire almost fowled plugs, have a long duration spark for light throttle lean mixtures, and are very good at high rpm and cylinder pressures.

If you change ignition systems, be sure and keep all the original components carefully stored so they can be refitted.


Do some Pelican searches on MFI, CMA, CMA2, and more. Collect all available information. Start yourself your own MFI book for both you and your mechanic.

Here is Check Measure Adjust (CMA)to get you started.

What degree of familiarity does your mechanic have with Porsche MFI? You (and he) want to become world class experts. We can help.

BTW, welcome to the Forum. You will find this an indispensable addition to be the caretaker of and enjoy your ‘69E.

Best,
Grady
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Old 09-14-2005, 03:56 PM
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