'93 Ford 7.3 IDI E40d computer issue help

[scott reavis]

I think my computer is toast but need to be thorough before sending it off for repair/replace. Any help would be greatly appreciated. Sequence of events over several weeks/month. Intermittent loss of tach signal coupled with E40 only having 4th gear in 'D', 2nd in '2', reverse ok. When tach signal returned all OK. Replaced tack sensor, did not fix, checked continuity of tach wires to first harness junction-OK. Checked TECA relay (both switch operation, continuity and with a 12V load-OK. Checked any fuse associated with tach or computer-OK. Tried to download fault codes with OBD1 and reader would not link to computer, checked reader with another vehicle-ok. Tried to download codes with paperclip method and noticed my "check engine light" does not illuminate. If it ever stops raining I was going to remove underfender to get access to computer. Any suggestions of next step? I would take the truck to a shop but none of the local diesel shops have much interest in tackling these early trucks.

 

[nostrokes]

Do you have any tranny shops in the area?? Preferably someone that has been around a long time they usually have lots of experience with these since does started using the in everything.

Check you're plug at the tranny, might have a loose wire or water intrusion.

 

[scott reavis]

Will check under at the tranny but not sure why there is no tach signal and the computer will not generate any codes

 

[trackspeeder]

Check the TCM connector and wiring for damage or corrosion.