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The idle problem won't go away

745 Views 2 Replies 3 Participants Last post by  Teutone
Car was idling at 900-1000 rpm in Park/Neutral. First i tried replacing the idle control unit with used one from eBay and cleaned the idle valve with carburettor solution. When i first started the car the idle was down to 600-650 rpm in park/neutral and i thought the issue was fixed. But after a while, the problem became worse, it now idles at 1400-1500 rpm.

This is what i found:
The voltage at the idle control valve is 4.4 , resistance is 10 ohms. When i remove the connector to the valve, the rpm raises above the 1400rpm to 1800rpm and when 12v is applied at the leads, the rpm cuts and the engine almost stalls. So looks like idle valve is working.

Also, if i press the idle control unit at certain place(on the smaller upper board bottom right corner) , rpm drops and if i press hard enough, engine stalls.

How to absolutely confirm it's the idle control unit that is the cause for the high idle?
1 - 1 of 3 Posts
You can of course buy a new unit, or try to find a good used one at the wrecker.
They tend to get hot, If the unit smells more than a little burned, don't even bother to open it, pick another one.
They are fairly easy to open, and looking at the board will tell you more.
In good rebuilds, transistors have been replaced, and extra heat sinks added.
1 - 1 of 3 Posts
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