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mark houghton mark houghton is offline
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Join Date: Jul 2008
Location: Central Washington State
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Originally Posted by 911st View Post
After some 50 pages of ignition learning and discussion I still do not understand if the solenoid dose or dose not have importance when it comes to getting boost retard out of the dual connection pot.

If we get boost to both sides of the pot, do we get boost retard?

Or do we need the solenoid to block the Vac-Retard to ensure we get boost retard?

That solenoid which is in-line with the vacuum retard line on the later dual pot just blocks the retard signal on cold start for perhaps a minute or so to help with establishing a higher idle. I believe it is then triggered through a time circuit which is part of the Lambda control system, and the valve opens to let vacuum retard the timing. As I said earlier, it really isn't needed. The AAR does a sufficient job of raising idle at cold starts in my opinion.

There is one more doo-dad (a thermal valve, non-electrical) that 's in line with the advance side of the pot. It's normally closed until about 150 degrees F, when it stays open. I believe its' function is to delay vacuum advance until the engine is somewhat warm - for emissions purposes. It, too, is most likely not needed and just another item to fail.

To answer to your question: No. I sure hope not anyway, or I've been running with 38 degrees advance on full boost all this time!!
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 04-05-2010, 11:55 AM
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