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Old June 9th, 2007, 08:51
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markaboo929 markaboo929 is offline
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Renix!!!!!!! why does it back my IAC motor all the way out????????

ok i know the renix uses a battery latch relay to power the ecm to know where the iac needs to be for next engine start up. BUT what in the hell does it fully pull it all the way in so my engine starts up and goes directly to 3000 rpm?????: i have to coinstantly tap on the iac to make it go back to normal..IT IS NOT THE IAC-all 3 i have put in do the exact same thing..can i just leave the latch relay out or just keep it constantly providing power to the ecm????? sucks man i wish i could make it so it does not fully retract the MOFO!!!!!!!!!ANY BODY MODIFY THERES NOT TO DO THIS????????
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Old June 9th, 2007, 12:00
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Re: Renix!!!!!!! why does it back my IAC motor all the way out????????

Quote:
Originally Posted by markaboo929
ok i know the renix uses a battery latch relay to power the ecm to know where the iac needs to be for next engine start up. BUT what in the hell does it fully pull it all the way in so my engine starts up and goes directly to 3000 rpm?????: i have to coinstantly tap on the iac to make it go back to normal..IT IS NOT THE IAC-all 3 i have put in do the exact same thing..can i just leave the latch relay out or just keep it constantly providing power to the ecm????? sucks man i wish i could make it so it does not fully retract the MOFO!!!!!!!!!ANY BODY MODIFY THERES NOT TO DO THIS????????
It is my understanding that the latch relay keeps power to the ECU and IAC for only 5 seconds after the ignition is turned off, allowing the ECU to reset the IAC. That is what I read somewhere anyway, not sure what the rest of the story is. IF you are having to tap it, it sounds more like a problem with it sticking or something. I would check and clean the throttle body, look for anyway the IAC could be hanging up in the throttle body, look for a poor electrical connection on the harness to the IAC.

Lastly I would REALLY suspect the TPS is bad, and that it is giving bad idle speed data to the ECU and the ECU is setting the IAC based on that bad data, or something like that. The tapping that is fixing the problem may not be affecting the IAC directly, It it may be afecting the TPS, which is a sign of noisy TPS that is going bad. You can test that by back probing the TPS idle voltage with a multi meter, using pins B & C on the 3 pin TPS conector. Do it while the TPS 3 pin connector is assembled and back probe the B & C connection or peirce the two B & C wires and read the voltage. Should be about .8 to .83 volts. Try it with power on, engine off, get a reading, start the jeep, and recheck the idle voltage, then tap the throttle body and see if the volatge is changing when the engine RPM drops. You can tapthe throttle body, and excercise the TPS sensor with the power off too, to see if the TPS is repeatable going back to the same idle volatge setting or not.
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