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Re: Odd idle when AMM unplugged but hesitation solved ?!$*@!~! Posted by Ari [Email] ![]() ![]() In Reply to: Odd idle when AMM unplugged but hesitation solved ?!$*@!~!, Tomee, Fri, 3 Aug 2001 13:26:59 Members do not see ads below this line. - Help Keep This Site Online - Signup |
But without the AMM, the ECU is still using the Oxygen sensor to control mixture.
There are two control loops here - one controls the fuel mixture - AMM and O2 sensor, and the other tries to keep the idle speed - AIC valve, which lets air into the system.
If the idle speed is a little low, the AIC valve will open to let more air in. But there's no AMM to detect it, so the ECU has to go by the O2 sensor. If the O2 sensor is a little slow in responding (as they get slow with time and age), there will be a delay in adding fuel, so there will be an overshoot of idle speed, and you'll yo-yo up and down. Idle speed isn't mixture, but the two are interrelated. Hesitation off the line is usually a mixture problem, but idle speed is the amount of air going in.
If you think the AMM is bad, replace it, THEN if you still have an idle problem, trace it down.
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