Topic: Mitsubishi Lancer Dire Help!

[Frostyboy]

I've attended a number of Mitsubishis with poor idle or stalling after either installing a new battery or after a discharged battery. The problem is related to the ECU memory losing its base idle setting.
Run the engine till normal operating temp, then remove the rubber bung over the idle bypass screw. Wind the screw out maybe two turns. When the ECU sees the RPM change without movement of the TPS it will drive the idle stepper motor to adjust the speed. Turn the screw back to where it was to begin with & I think you'll find the stepper motor will then revert to the correct position & idle speed will return to normal.
This won't fix the noise you speak of, but it should solve the stalling issue.
The rubber bung you are looking for is maybe 8-10mm in diameter.
Cheers.

[Retro Rocket]

My Daughter has an earlier model Lancer but it has the 4G63 twin cam engine {not standard} but it does this exact same thing, where is this "idle air motor" to which you refer ? I have replaced all the sensors but the problem persisted?

Mick

Mick, on most EFI motors, the throttle butterfly is closed all the way, with no adjustment. The idle air control motor screws a valve in or out, to allow air to bypass the throttle, and adjusts the idle speed under computer control. It's usually mounted on the throttle body, or on the manifold near when the TB attaches.

Thanks mate, i'll have a look and see what i can find.... The wire that goes to the TPS wasn't attached very well so i thought it may have been that but it made no difference.

Mick

[chrislib]

The low/crappy idle is probably because when the batt went dead it also cleared the adaptive memory from the engine computer. The computer compensates over time for the grunge that devlopes in the throttle body and when you lose elec power the ecu thinks it is working with a clean throttle body, hence the low idle. Two choices, you can leave it as the computer will eventually relearn and compensate or you can clean the throttle body. Either way it`s not really a problem.

[campbmic]

Thanks Frosty and Chris this is good news! I will look for the idle screw today and see what I can do!

[campbmic]

Made it back to Dallas and the problem seems to have pretty much gone away after the 2,000 mile trip back! Thanks guys