Question about 1989 Mitsubishi Mighty Max
For the life of this truck it has always idled high. Not sure if it has something to do with my problem or not. Lately when I've been driving it I get to about 35/45 mph and it bogs down, stops accelerating, and the engine will cut off. I put it In neutral and start it back up. Maybe get another mile or a half down the road before it does it again. Also there has been a loud whining sound (like a belt) but not a belt. Please help
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Posted on Jan 02, 2017
It sounds like your balance belt might be broken. I have a 1991 Mighty Max that experienced the same problem. My water pump started leaking and as I was replacing it, I discovered the balance belt was also broken after removing many parts on the front of the engine in getting to the water pump. It's a small rubber belt that turns opposite of the crankshaft to keep the engine from shaking at idle. My engine is still torn down, as I don't know how to replace the balance belt. Sure could use some advice on this repair.
Posted on Oct 25, 2009
not sure about engine light as i dont think it has one at this age but the CO2 is caused by either a O2 sensor of which you will only have one in front of the cat or the cat as well is past its sell by date ,Test the O2 sensor with a automotive meter for readings and continuety in the heater circuit ,but as a rule i change both at the same time as a four wire sensor is not a lot of money ,well a universal one isnt anyway and make sure the air filter is clean ,if they argue about the engine check light then go to dealer and ask for a copy of the certificate of homoglonation as this will state if it has a light or not
Posted on Mar 07, 2011
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SOURCE: 1994 Mitsubishi Mighty Max, 2.4
Hello brian..these are great little trucks, i have a 87 (hitachi carb) with over 300k on it---still going strong and gets good mileage. Sounds like a fuel delivery problem on yours--- You can test the fuel pressure and the pressure regulator with a manual gauge...autozone has loaner tools if you dont have a fuel pressure tester. You should have aprox 36 psi ---remove the vacuum line on the pressure regulator with the engine running, the pressure should come up about 5-10psi, if it dont the regulator is bad. (Make sure there is vacuum on that hose) Make sure the MAF sensor is clean, if dirty clean it with MAF sensor cleaner, don't use brake cleaner.
Check for vacuum leaks around the manifold and emissions hoses...a good way to do this is with carb cleaner...spray it on the areas you are checking, it engine rpm change, you found the leak.
Also check the coolant temperature sensor, if it is out of range it will send a false signal to the engine controller, the controller will not open the injector circuit to squirt enough fuel under a load.
I hope this helps & good luck with your mighty max.
Posted on Aug 27, 2011
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