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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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[QUOTE=DailyDriven'88;4968462]No O2, but the dizzy does have the thermo valve and the other switch still inline with the vacuum lines. I believe they are working correctly. The idle will kick down after a minute or so during cold starts. I believe thats one of the functions of either one, or both, of those dizzy devices? Can I simply leave those items out of the loop for testing purposes? I think the answer is yes but just double checking. Frequency valve still installed. How do you check its function? [QUOTE]

You can just route arouind those solenoids and valves, and you would primarily just lose the additional advance for the first minute of cold start. Instead, the vacuum retard would be there right from the start instead of being delayed. To be honest, I suprised the solenoid even works since your O2 sensor is disconnected, but it's obviously an isolated function controlled by the same box under the seat that controls all the other Lambda functions. I was just wondering if the solenoid was being spassmic; stopping retard/allowing retard either because it's triggering when it shouldn't be or it's internal mechanisms are beginning to fail (i.e. leak). If you were to unplug and then plug back in your retard vacuum line at the dizzy once every half second, would you get the same weird idle?

Testing the frequency valve....well, all you can really do is listen to it buzz (engine off, key on, force the pumps to run and you'll hear it buzz away). Unplug the connection, plug it back in and listen to it. If it failes, you'll have problems with very lean conditions. Can't run without it (at least not without adjusting all 6 fuel plungers in the fuel head to compensate).

This is a diagnostic mystery. I just seems to me that you're chasing a vacuum issue somewhere.
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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.

Last edited by mark houghton; 10-23-2009 at 11:06 AM..
Old 10-23-2009, 06:57 AM
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