Is my pcm srewed

[motoman196]

I have a 94 ranger with the eec-iv pcm. I have been replacing sensors and clearing and checking codes using the jumper wire and test light procedure. Well the other day I replaced the ect and reset the codes. Now My check engine light comes on like two to three seconds after startup. So I hooked the jumper wire and test light up and get nothing. Like it won't go into test mode. When I used to check it koeo you could here the fuel pump prime a few times then you could here valve opening and closing now I get nothing. Truck still runs fine though? What the heck?

 

[Joelzme]

On my 91 You can reset the ECM by pulling the jumper cable during the test but I have a ODB-1 system and not the newer ODB-II. That will clear out all the codes without having to disconnect the battery.

Have you tried doing that and see if it fixes the problem with not being able to read them?

 

[motoman196]

Yes I have pulled the jumper wire while it was spitting codes in the past to clear it. I did that this time after changing the ect. Went to start it up and the cel immediately came on. In the past when I would clear the codes it would take about a 10 min. ride down the road to kick a light again. Now I've got the light and am unable to pull the codes.

 

[motoman196]

forgot to mention my truck has yhe old obd-1

 

[Joelzme]

Sounds strange to me. Have you tried putting the old sensor back in to see if that correct the problem with the CEL? Maybe you got a bad replacement or not the correct one, but that's just a guess on my part.

Keep us posted.

 

[motoman196]

Haven't thought to do that yet. I'll give it a try.

 

[motoman196]

Well, I tried putting the old sensor back on and it didn't help. I think something must be wrong with the pcm.