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mike_a_mechanic, Mitsubishi Mechanic
Category: Mitsubishi
Satisfied Customers: 51
Experience:  17 years experience as a auto mechanic, foreign and domestic.5 years running my own repair business.
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I am hoping you can help. I have a 1997 Mitsubishi Challenger

Customer Question

I am hoping you can help.
I have a 1997 Mitsubishi Challenger 2.8
VIN/Chassis number - K971100184
Engine number - 4M40184.
It has developed a fault whereby the car although starts blows black smoke when depressing the accelerator, also the rev counter has stopped working.
I have replaced the front seal on the fuel pump and also the throttle position sensor as this was diagnosed by my local Mitsubishi dealer. As this car is a grey import the result of the diagnosis was at my own risk and fully accepted that any cost associated would be picked up by myself. so I am where I am £500+ spent and a car off the road now for 5 months.
Any suggestions would be greatly appreciated, my next step was to replace what I believe to be the sensor that provides the signal to the rev counter which is mounted on the fuel pump - it has a part number engraved on it 767-07, but this is another gamble.

Thank you

Submitted: 4 years ago.
Category: Mitsubishi
Expert:  Shantal-Mod replied 4 years ago.

I'm Shantal and I'm a moderator for this topic.

We have been working with the Experts to try to help you with your question. Sometimes it may take a bit of time to find the right fit.

I was checking to see if you had already found your answer or if you still need assistance from one of the Experts.

Please let me know if you wish to continue waiting or if you would like for us to close your question?

Thank you,

Customer: replied 4 years ago.


I can confirm I still require assistance as I am struggling to identify the source of the problem.

Any assistance would be greatly appreciated.

Kind regards


Expert:  Shantal-Mod replied 4 years ago.
Hello Ian,

Thank you for getting back to me. We will continue to look for a Professional to assist you.

Thank you for your patience,

Expert:  Shantal-Mod replied 4 years ago.
Hello Ian,

I apologize as we have not yet been able to find a Professional to assist you. Do
you wish for me to continue to search for someone to assist you or would you
like for us to close your question at this time?

Thank you for your patience,

Customer: replied 4 years ago.

Yes please

Customer: replied 4 years ago.

yes please

Expert:  Greg replied 4 years ago.
Name is Greg, My goal is to provide you with excellent service – if you feel you have gotten anything less, please reply back,

Did you always have this problem .

Was any work done on this engine to cause it to blow black smoke .

Has the basics been done for black smoke diagnostics like air filter blockage

Rgds Greg
Customer: replied 4 years ago.

Hi Greg

Thanks for taking the time to try and help me.

The car has never had any work done to it other than routine services and an exhaust system replacement.

However there is some history leading to this fault which I forgot to mention. From cold the car would start after warming the glow plugs by turning on the ignition 3 times then turn the key all the way to engage the started motor. The car would drive approximately 1/4 mile then cut out, at this stage it would be a devil to restart, when it eventually did restart there would be clouds of black smoke. After this initial problem the car would continue running fine all day, I replaced the heater plugs which did make a difference but not totally solve the problem. The air and fuel filter was changed for new Mitsubishi ones in October last year at the same time I replaced the front seal on the fuel pump as recommended by the guys on the Mitsubishi owners forum. What I did fail to mention was that when I took the fuel pump off I noted that there was heavy oil deposits around the butterfly valves that connect to the Intercooler. Other things I noticed that when sat in the cabin whilst trying to start the car there was some electronic / electrical clicking coming from behind the dash on the left hand side.

I am really scratching my head on this one, I think I have one fault that connects the rev counter to the poor starting and lack of power. But is it 2 unrelated faults that just happened at the same time, I just don't know.

What I have just remembered was that when the fault arose prior to it becoming undriveable my wife had called me saying she had broken down about 20 miles from home, I arrived at the where she had broken down about 40 minutes later and with much swearing got it to restart, when following her home the car would let out a little black puff from the exhaust about every 3 to 5 seconds for the duration of the journey.

The problem as I see it is that the engine does not know where it is as the throttle is either nothing or flat out within a slight amount of depression of the pedal the remainder of the depression has no effect, hence the reason I purchased a new throttle position sensor (£450 quid down the drain). Now the car will start but when you turn it off then it will not restart typically until the next day.


I hope this helps with your diagnosis. I am at the point of scrapping it but it is a super car that is structurally sound and her that must be obeyed insists that I can repair it even though 2 of my local garages have given up. I guess I am hoping you can help pull a rabbit out of a hat or any other such magic trick.


Kind regards



Expert:  Greg replied 4 years ago.
Hi Ian .

First check the compression of then engine, then lets work from there ,as i want to know if its worth repairing this engine .

Customer: replied 4 years ago.

Ok I will have to go and get a compression tester in the morning and get back to you if that is ok?


Expert:  Greg replied 4 years ago.
Sure no problem get back to me when you can .

Regds Greg