I do not get to drive my 91 enough and it has been sitting for about a month. Prior to that I had driven it on the weekend and the tranny shifted fine. The motor has been starting hard and running rough until warm up. Today I cranked it up and it continued to run rough and the tranny would barley move it in forward (slipping real bad) reverse was fine and shifting it into first it would do a little better but not much. This tranny only has about 25K on the rebuild and has been doing fine. Checked the fluid and it is not over filled or burnt looks good. I then proceeded to pull codes and noticed my fuel pump does not shut off in the run position with the motor off. I then proceeded to pull codes with the little code puller you get at autozone for these EEC-IV units. Nothing, i thought maybe the scanner is bad (it is older) I then did it the old fashioned way by jumping the connector to flash the CEL and nothing. I cannot get the codes to pull. This makes me feel that all is the same or similar problems. The CEL is on with the key in the run position but no flashing. Any help would be greatly appreciated. I am in the process of trying to get this thing running good to sell it Thanks.

 

Check to make sure you have power on pins number 1, 37 & 57 with key on and pins number 40 & 60 have a good ground.
If so change out the Computer.

 

FUEL or EEC Relay could be bad or getting there.

 

Thanks subford, I checked the pins and was getting proper voltage at all those pins any other ideas?

Prozon
In my experience with the relays especially the eec relay is that if they are bad you will not get a CEL at all since no power to the eec. Proper power is getting to the eec. Fuel pump relay is working. Thanks

 

One other thing I noticed is that when I pushed my OD button it did not turn off, I did not get any reaction from the button.