'91 4-Cyl OBD-I Problem

[Campranger]

My son was on his way home with the '91 Ranger, 2wd 4 cylinder. The CEL came on so he stopped and plugged his OBD-I code reader in. He got a couple codes, but when he unplugged the reader, the engine died and would not restart. I just towed him home. Is there a fuse that could have blown when he unplugged the tester? He needs it back badly by Monday. Any thoughts?

 

[Haywire6000]

Check the fuses under the hood, should be three, fuel pump, ecu and something else I can't remember what it is. But I would start there. Also what were the codes?

 

[Campranger]

I think he was doing it wrong, as he probably should not have had the motor running at the time. Might have contributed to the problem. He got a code 898.

 

[Campranger]

I have checked all the fuses including the ones under the hood. They are all ok.

 

[RonD]

898 is not a valid code, 98 is an invalid Computer program code.
Most OBD I were 2 digit codes but there are some that had 3 digits, those don't go above 6XX

Have you disconnected negative battery cable for 5 minutes, then reconnected it, that will do a hard reset of PCM(computer).

Also check the connector on the PCM, they often get moisture on them over the years, simply removing connector and reinstalling can get PCM working OK again.

Can you hear the fuel pump come on for 2 seconds when key is turned on?

 

[Campranger]

We will have to recheck the codes. I am not sure if the fuel pump is working. I can't hear it, but I am working outside in -18 degrees and the wind is making it hard to hear. The fuse under the hood is good; is there another related to the computer or fuel pump in the panel under the dash? Daylight tomorrow I will be checking for spark. I have disconnected the battery for a couple hours.

 

[Road Angels]

no run

He should have done a key on engine off test, then a key on with engine running test, then shut the engine down and key in the off postion when you pull the code reader, you can jumper the fuel pump at the diagnois connector witch will apply a straight ground to the pump taking the pcm out of that circut, Iam wondering if there was a suspected problem since he had a code reader with him, that is not telling the whole story here witch might help us help you???? also does he have gas in it you can check this by using a rag and screw driver to 1 open the valve for fuel and 2 a rag to keep it from spraying all over, you should cycle the key a few times be for checking, if no fuel at the valve but you can here the pump prime then your fuel filter is plugged or the crap in it has frozen in the cold sub temps, dont count on what the fuel gauge says

 

[Campranger]

I have decided this one is over my head, so I hauled it to an auto electric shop today. Rather sad to give up the battle, but it is too darn cold. Thanks for your help, neighbors!

 

[Campranger]

Problem Solved

Update: A connector had come partially disconnected. It looked connected, but appearances are deceiving. He fixed some other wiring issues while he was in there. Also, the auto electric guy found a wire on the exhaust manifold. Fixed, run and sold.

Now for the other three family Rangers...