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1991 Mitsubishi Mirage Fuel Pump

Took my mom’s Mirage in for a tranny problem (automatic). The shop kept the car for several weeks. I discovered that they farmed out the job and demanded the car’s return. It wouldn’t start, so I had it towed to another mechanic. They informed me that the first mechanic had removed the engine’s computer and had not re-installed it. It took a few sdays to get thte first mechanic to deliver the computer. It is installed, but the second shop says the fuel pump isn’t working now. Is there a possibility that the engine’s computer controls the fuel pump - and if so, that the computer may have gotten damaged or replaced with a faulty one? Is there a way to identify a car’s engine computer to the VIN?

A 1991 Mirage engine computer loaded with the car’s vin #? I doubt it very much.
Your problem,right now, is getting the engine started. If the second shop doesn’t know how to troubleshoot a no-start, you’ve ended up with another incompetent mechanic.
There might be friends, or neighbors, who know of an able mechanic. Ask around.

On OBD2 cars some systems require you to enter at least part of the VIN for programing, I don’t think your 91’s “computer” can be linked to your car by VIN

It is interesting that the cars “computer” was removed to adress a transmission concern (you don’t state what the transmission concern was)

I have seen customer’s cars used as parts donors to help diagnosis another car the shop had in at the same time, this would be quiet a coincidence, was there another Mirage in the shop when you went to get your car.

O.S is correct,no VIN writing,this car has a TCM and an ECM.

perfect case of wrong tech wrong car,what was the original problem?

and yes could be another bad puter,I have several mitsu puters on my bench waiting for parts that are on order(sorry but I will not reveal why they fail)but yes you got a crappy used or reman.(possible but not for certain)


good luck

The tranny was operating in “limp mode” (high gear only when shifted into drive). I have some leads on fixing that. The big question to me is if the fuel pump’s problem is caused by the engine’s computer. One source of information says that the computer does control the fuel pump. OK, what’s an easy way to find out if the computer is the problem? Thanks for all the inputs.

Here are instructions for testing the fuel pump Here are the wiring diagrams which show how the fuel pump is powered: All the models, and the years close to 1991, will be close to the wiring in your car. To get the specific wiring diagram for your car, you need a repair manual.
In general, the engine computer turns on the MFI relay which powers the fuel pump, the fuel injectors. Your repair manual will tell you what signal the engine computer has to receive for it to turn on the MFI relay. You would check for the voltage to turn on the MFI relay, and, make sure the ground wire has near zero resistance to ground.

Perfect! That’s just the info I need. Thanks a lot everyone!