missing, popping back thru inake
07-05-2013, 10:18 AM
#1
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Location: west of st louis mo.
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missing, popping back thru inake
hi, my name is mike, aka "tailgunner". my girlfriends 1992 4X4 laid down on her. i think it if the ecm. i value you opinion. cant find my code reader. think it is in storage, anyway. started running rough and missing. very hard to start. plugs were shot. put a cap , rotor, wires and plugs in it. no better. checked out all vacuum lines. repaired the bad ones. thought possibly an injector. they all ohm out ok. what im seeing on the engine off, key on, injector harness connections is 12 volts. book says 10.5 volts. i can pull fuel pump relay and hard wire it and get good engine start but still have miss and pop thru intake. i can pull injector wires and no effect, new one on me. i think she has a bad ecm with a hard failure due to the fuel pump over ride and the goofy injctor thing. timing is good. no intake leaks. opinion would be appreciated. 
07-05-2013, 02:40 PM
#3
Unplug the neg cable for 5 mins and put the ecm into a learning mode. Drive it a few miles and then pull the codes...then, do it again. if the codes change or they don't register at all, it's prob the ECM. About $125 from a reputable remanufacturer. I have had 2 replacement ECM's in my 90.....
