Mitsubishi -90 start problem

SV1JANSSON

MEMBER
1990 MITSUBISHI MIGHTY MAX
6 CYL
4WD
MANUAL
75,000 MILES

I have a Mitsubishi Mighty Max 1990, 75000 miles, with 3 l engine. I have two problems with the car and it is impossible to find a car repair workshop in Sweden that knows anything about this model.

1. The lamp "check engine" lights very irregularly, sometime for several hours and sometime for a few minutes. It can also stay off for several days. I can not see any difference in behaviour of the engine when it is on or off. This has been going on for 2 years.

2. In the last 4 months I have starting problems. I have to run the starter very long before ignition and when it starts the power is weak. After been running for a couple of minutes the engine behaves normal. It starts easier after using the motor heater or putting some startgas in the air filter. I have checked all sensors and cables and assured that there is a good contact. It must bee some failure in the fuel injection system. Can you tell which one of the boxes that is bad or if it is the temperature sensor.

5 Replies

RASMATAZ

MECHANIC
75,992 POSTS

https://www.2carpros.com/articles/service-engine-soon-or-check-engine-light-on-or-flashing

Have the computer scanned for code/s-you have a problem within the engine management system that caused the CEL to turn on-This is your starting point of diagnosis,finding out what's going on

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Tuesday, April 12th, 2011 AT 8:22 PM

SV1JANSSON

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4 POSTS

Even a Mitsubishi service center can not read codes from the computer in this car. Is second problem related to this first one?

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Wednesday, April 13th, 2011 AT 6:58 AM

SV1JANSSON

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4 POSTS

My Mitsubishi service center has the hadware to analyze the car computer but probably not the correct software. Can you specify the software that is required for Migthy Max and where my service center can buy it?

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Wednesday, April 13th, 2011 AT 7:51 PM

SV1JANSSON

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4 POSTS

Dear rasmataz, sorry but yor answer did not help me at all. Please describe how to read out the codes, which equipment is required and what the codes mean in clear text.

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Saturday, April 16th, 2011 AT 8:34 AM

RIVERMIKERAT

MECHANIC
6,110 POSTS

There are hundreds of possible codes, so listing them all would take too long.

The starting problem, does the engine turn over slowly? You said it is easier to start after using the motor heater or using starting fluid. Have the battery checked for load voltage. Also, Sweden, I'm guessing that we're talking temps around zero Celsius or lower? What oil are you using in it? Are you using a cold weather, light weight or a warmer climate thicker oil?

If the battery is fine, check each plug wire for quality of spark. If the spark coming from the wires is anything less than a bright blue one, replace the coil.

I'm not surprised the dealership doesn't have the right scantool for that year, it's fairly old. Unplug the battery, leave it unplugged for about 30 minute sor so. This SHOULD reset the computer as far as codes are concerned. If the Check Engine Light comes back on, find a smaller, independent shop to read the codes for you. Usually, at that age, the problem is the Oxygen sensor. How is the power output? If it's pretty weak, take a look at the catalytic converter, if it has one.

One way to check the codes yourself is as follows:
Find the diagnostic connector under the steering wheel.
Run the truck until the engine reaches normal temp.
Insert a jumper wire with a small 12 volt bulb between the upper right and lower left locations on the connector.
Turn the key to "Run" and count the flashes of the light. This will be your trouble code(s).

This won't always work, but should with your vehicle.