1991 Mitsubishi Mighty Max 2

  • 150,000 MILES
1991 Mitsubishi Mighty Max 2.4L base unit. VIN JA7FL24W7NP004263

The engine seems to bog down like its out of fuel. I have replaced the fuel pump, gas regulator, repaired the crappy job done on the ecu and replaced other components due to stress.

I don't have a computer, but if I did, wouldn't have an idea where to hook up, nothing is by the fuse panel, and on the passenger kick panel was the ecu and fuel injection relay. I am getting pressure from the pump, I removed the return from the pressure regulator and it was coming out of the point on the engine. I had a very hard time with the nuts and bolts due to age and couldn't replace the fuel filter because I didn't want to cause damage, and I was getting fuel on the output of the regulator.

The pump really needed to be replaced, the filter just fell apart when removing the pump, the tank was full of rust, I did mess up the fuel level sending unit, but it wasn't like it really worked before, but is still attached.

If you can tell me where to find the computer interface, I have read about how to test with analog meter. Have many years in electronics so that should be pretty easy, directions seem very straight forward. Guess this is another instance that a digital doesn't have a fast enough reaction time to be used, I do love my old faithful meter. Also can't use a digital meter when troubleshooting a radar unit because of the reason above, and I learned this the hard way many years ago.

I have read where this could be the coolant sensor or the O2 sensor.

Thank you very much, if you require additional information let me know.
Do you
have the same problem?
Monday, March 18th, 2013 AT 10:18 PM

1 Reply

It sounds like you have done quite a bit of work already which is great!

A few things worth checking-

Is there a check engine light? If so what code is the computer telling you is wrong? (IE 02 sensor, fuel injector ect)
Assuming it is throwing a CEL, you can use that to get closer to the issue at hand and test and replace parts as needed.

If there isn't any DTC, next I would check out the injectors and make sure that they are working without any issue and they are not clogged.

Assuming the injectors all test good, I would then check the spark delivery. IE cap, rotor and spark plugs.

If you want a different ECU because you are afraid that yours is shot http://www.car-part.com (assuming you live in the U.S) can get another one for cheaper then you can probably otherwise.

Make sure that your fuel system is rust free, I am worried that fuel filter holds the key to your problem.... Installing a new one : /

Good luck!

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Monday, March 18th, 2013 AT 11:05 PM

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