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Discussion Starter #1
Hello everyone,

I'm new to posting on this forum and searching for any ignition and/or fuel control systems tuning information on, specifically, the 1980 iteration of the Alpina B7. My customer's car has a Pierburg type 52700101 mechanical fuel distributor (Alpina sourced this from an aviation application). The ignition system uses three dual outlet coils, crank-fired from the flywheel (Alpina simply drilled a hole in the bellhousing for the pickup). The ignition box has absolutely no ID tag or external adjustment. After waiting 14 months for Pierburg's contractor to complete the rebuild of the fuel distributor, the car still won't tune properly. The installed Pierburg fuel pressure regulator is unobtainable through any of Alpina's sources and I have no operational specs on it. The water temp sensing auxiliary air valve (633 CSi type) was previously replaced, along with spark plugs and plug wires. The car runs puke rich according to my wide band (no cats installed). Idle is somewhat erratic and none of the fuel/intake air system adjustments alter the idle rich mixture. Initially, I had to open the flapper door air bypass circuit of the mechanical fuel distributor (same function as the air bypass on an L-Jetronic air flow meter), to full open. This helped with idle quality, but has since become less functional. Both the mechanical throttle plate stop on the throttle body and the large brass idle air bypass screw on the throttle body affect idle speed, but not idle CO% when targeting a 1000 r.p.m. idle speed. This Turbo management design is horribly unsophisticated by today's standards and must have been a bastard from the get go. Susan at KSK distributing (Alpina USA) has been a great help, but doesn't know anyone in Alpina's organization who can assist me. I realize the fuel injectors may be an issue, but at $160/US each, it's a hard sell to the customer after spending $3500.00+ on the fuel distributor. And, even with jacked up injectors, I would expect a bit more tuning resolution, but perhaps not. My shop is at just over 5400 feet above sea level, although the Pierburg aviation unit was applied for altitude compensation with a boosted motor. Does anyone have practical hands-on experience with this system? Any help is greatly appreciated.

Thank you,

Mark
 

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Have a search for Pierburg on this forum. There are a few members that have done some great analysis on the topic.
 

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May be here?

 

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Yes, search for threads I have started or been heavily involved in. We have discussed how to adjust/tune the pierburg setup. It;s CIS, so it;s not that difficult. If you can work with Bosch K-jet, you can work with this.
Can also email a copy of the original Pierburg manual. In German, but still very useful, and the critical bits have been translated by various folks.
 
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