93 Jeep Grand Cherokee starts but only runs for 2-3 seconds. I have replaced the fuel pump first, then the fuel filter, the alternator, the battery, and finally the starter. I was told to check the ballast resister, but can't find it anywhere

Check the fuel pressure.It sounds like you may have a weak fuel pump.If its not within the specs then replace the fuel pump and filter.

Take 2 screws out of PCM and replace with shorter ones

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If the check engine light does not light up on the dash when you turn on the ignition, at those times when your jeep doesn't want to start, then your main jeep ecm is in need of repair. The fuel pump relay will get energized only after that check engine light comes on. It's a known problem, especially with the first and second year production Grand Cherokees, 93 and 94.

Clogged fuel filter and/or bad fuel pump

this is a fuel problem, fuel pump is bad, or fuel filter is clogged up. check to see if fuel pump is working. check fuses and relays if it does not work. to rule out a bad fuse or relay.

Based on what you noted, your system is not drawing too much, it is overcharging. Determine if you have an external regulator in your system (depends on alt. make and alternator design) Many of the Jeep systems have the voltage regulator as an integral part of the main computer. Likely it has failed. Also make sure that the charging system is properly grounded and the battery is fully charged and can undergo a load test without substantial voltage drop. If it cannot, it will over-work the alternator.

Battery should be around 12V the alternator puts out 14V. Sounds like a fuel problem, leaking injectors or injector's O-rings. Weak or faulty fuel pump, clogged fuel filter, faulty fuel regulator. Try this, when starting the car while cold. Put the key all the way to the ON position, wait five to ten seconds then crank the car to start. It should start the first time the longer you give it the more fuel pressure there will be to start the car.

Does the vehicle crank for extended period of time upon first starting? If so the fuel pump needs replacing.

how do you reset the computer for 1995 jeep grand cherokee changed the starter yesterday now it only runs 10 seconds and dies some one said to reset conputer but i dont know how tried the internet no luck please anybody help thanks ken

Could be a sensor.I'm thinking more along the lines of a fuel pump or fuel filter.If the fuel pump is going bad..similar symptoms.Would be advisable to install a pressure gauge at the engine,and check fuel pressure when it's acting up.