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Doug, ASE Certified Technician
Category: Mitsubishi
Satisfied Customers: 6953
Experience:  Mitsubishi employed and Factory trained ASE certified technician
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What is the failure rate of a pcm 2009 mitsubishi eclipse

Customer Question

what is the failure rate of a pcm for a 2009 mitsubishi eclipse 2.4 liter? it came in with the converters so plugged it wouldnt even run. now converters replaced im looking for the root cause of the rich running and sputter problem. timing belt has been replaced and checked and double checked for proper time. front o2 sensors have been replaced with the converters. coolant temp sensor reads right on the scanner. crank sensor has been replaced during t-belt job. cam sensor has been scoped and is putting out wave pattern. canister vent solenoid hose has been pinched off, injectors have been ohm checked and pulled up on the rail and leak down checked and spray pattern checked. its dumping fuel and flooding out. i can run the car if i stepp it down then hold it at around 1000 rpms, it sputters and gives a random missfire code but no cylinder id code. it doesnt sound like a uniform ignition miss and i have tryed coils as well. thinking the pcm has failed and went into enrichened loop?
Submitted: 1 year ago.
Category: Mitsubishi
Expert:  Doug replied 1 year ago.


I have worked for Mitsubishi since before this model was released and I can count on one hand how many bad PCMs I've seen... to say they are reliable is an understatement for sure. When I have seen them fail it is exclusively for charging problems or throttle body operation problems. Never anything like you describe with fueling.

Were aftermarket cam or crank sensors used on the vehicle? This era of Mitsubishi has nearly zero tolerance for aftermarket hall effect sensors and can lead to this behavior.
What is your operating fuel pressure (engine running pressure)?

Was the timing belt changed trying to correct this issue, or had the belt failed?

Customer: replied 1 year ago.
it was an aftermarket bwd crank sensor. fuel presure is 42-45 lbs timing belt was inspected because of this problem (suspected jumped time)but replaced due to age timing was on. I should have mentioned that the maf and map have also been replaced. the cam sensor was in a bwd box but had mitsubishi on the sensor.
Customer: replied 1 year ago.
front o2 sensors are switching downstreams are staying at high 800s low 900s
Customer: replied 1 year ago.
new converter is glowwing already
Expert:  Doug replied 1 year ago.


When you changed the converters did you do the big under car converter too or just the manifold one?
If both, are you able to set up an auxiliary fuel supply (pressurized fuel can etc) to rule out any fuel quality related issues?

Expert:  Doug replied 1 year ago.

Also if we could put the original cam, maf and MDP sensors back in that would be helpful to rule out aftermarket related issues (Again this model does not get along with chinese reproductions unfortunately).

Customer: replied 1 year ago.
i did drain the fuel into a mason jar and let it settle not cloudy and no water but i can get a pressure can setup just to make sure. manifold converters have been replaced and rear converter has been eliminated(behind sensors).
Expert:  Doug replied 1 year ago.


Lets get the pressure can with fresh fuel (not from the tank of course) set up and compare behavior, and the original sensors reinstalled too while we are at it.

Customer: replied 1 year ago.
ill swap them back
Customer: replied 1 year ago.
will do, im running a shop and im the tech so itll take just a bit as i have the rail up for testing. i do appreciate your promptness to respond.
Expert:  Doug replied 1 year ago.

No problem at all. I will be here off and on throughout the day and evening, just post when you have some results and I will get back with you as soon as I see it.