Adjusting idle mixture bypassing computer

Feb 10, 2012 3 Replies

I am seeing several cars from the early 90's that are idling rich and we = can't figure out what the problem is. After checking the simple things =



- plugs, vacuum hoses and connections, next idea was the computer was = not getting the right signal from the mass air flow sensor. Swapping = that out didn't improve anything.



All we really need to do is manually adjust the idle mixture, but as far = as I can tell this is not possible due to all the controls coming from = the computer.



Anyone run across this before and have an idea what to look at next? Or = how to bypass the computer and adjust the idle mixture=20



Thanks in advance.



Bob


bad temp sensors - could be 3 of them bad IAC, MAT, MAP, MAF bad O2 sensors - could be 4 of them bad injectors air leak between intake and MAF blown pressure regulator

figure out what the problem is.

idea was the computer was not

didn't improve anything.

I'd suspect the IAC myself...

and we can't figure out what the problem is.

connections, next idea was the computer was not

that out didn't improve anything.

Thanks, Peter. Looks like I'll need to price out some parts and start = swapping the out. I'm not that up on emissions systems. Found this... =

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