Thread: Idle Questions
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Old 04-19-2003, 02:32 PM
Rato73 Rato73 is offline
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Join Date: Jan 2003
Location: St. George, UT
Posts: 11
Idle Questions

After sorting out some misconnected vacuum lines (DPO) I have resolved some cold start and acceleration issues. Now it seems that when I adjust the mixture lean enough to get rid of a stumble when pulling from a stop, the idle surges and stalls randomly when coasting to a stop, like the mixture is correct for acceleration, but is too lean for a smooth idle. The stalls are random and the engine usually fires right up again. The acceleration stumble is worse some days more that others. My theory is that the problem may lie in either the OVP or the idle control valve. Also, when accelerating, the car seems to continue the acceleration even when the pedal is brought back slightly and when brought back more, rapidly decellerates like a binding linkage releasing although it checks free.

Now, the questions:

Is the position of the idle control valve open (more air) when no voltage is applied? Would a sticking ICV cause a too lean mixture at idle?

Ditto for the OVP. Would a lower voltage output from this cause a leaner mixture at idle?

I have the timing set at TDC (without vacuum). Would a sticking retard mechanism in the distributor cause the "binding throttle linkage" feel upon acceleration?

I just want some direction on where to go from here without throwing a lot of new parts at the problem.

Even a broken clock is right twice a day.

'84 380SE
'66 MGB Roadster
'85 Mazda RX7
'91 Chevy P/U
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