2002 Mitsubishi Eclipse Car starts but won't idle

BRANDYWINE3478

MEMBER
2002 MITSUBISHI ECLIPSE

Engine Mechanical problem
2002 Mitsubishi Eclipse 6 cyl Automatic 152000 miles

The problem started when my daughter charged her cell using the car charger. She said she left the switch in the "on" position while doing so. When I tried to crank it, it wouldn't turn over or anything but there was a constant clicking coming from the ECU. So I replaced that thinking it would fix my problem. The car immediately started up with no problem until I got about 7 miles down the road and slowed down to turn into a parking lot. It died. It will now crank but won't idle unless I keep my foot on the gas. I took it to Express Lube to have them run a diagnostic. They said the only thing that came up was 2 of the O2 sensors were bad. So I then replaced the upstream O2 sensor located in rear manifold/exhaust pipe & upstream O2 sensor located in front manifold/exhaust pipe. It cranked right up and I let it sit and idle for at least 30 mins. I then turned it off then tried to re-crank it and I have the same problem: crank but won't idle.
Can you help?

1 Reply

CARADIODOC

MECHANIC
33,741 POSTS

Hi brandywine3478. Welcome to the forum. Sounds like you're "getting wrapped around the axle" looking for the wrong things. It sounds like the original problem was the battery was run down. Clicking relays are a common sign. Either way, a dead battery or unplugging the Engine Computer will cause it to lose its memory. Short and long term fuel trims will be relearned while driving and you won't notice that taking place, but until it relearns "minimum throttle" the computer won't know when it must be in charge of idle speed. The classic symptom is stalling when coming to a stop.

I only know the relearn procedure for Chrysler products but Mitsubishi and Chrysler have a lot in common. One other person said this worked perfectly. To meet the conditions that tell the computer to relearn minimum throttle, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the brake or gas pedals. There is likely nothing wrong with the old computer, but if you put it back in, you'll have to do this procedure again.

Caradiodoc