The Diesel Stop banner
1 - 9 of 9 Posts

·
Registered
Joined
·
24 Posts
Discussion Starter · #1 ·
Ok guys I have fixed a lot of problems lately and a new one is my truck will drop rpms at speeds above 6mph. If you try to just keep going it will die eventually. If you slow down to less than 50mph it will stop... Speed back up and repeat process.... The OD light is also flashing but does not flash all the time and the truck is not in limp mode because I can make it to these speeds..need help.
 

·
Registered
Joined
·
3,553 Posts
When the OD light flashes you have stored transmission codes. You have to pull the codes and post them before any help.

If you keep driving like that, you may possibly damage the transmission. It may be way overheating.

You can correct your post by going into EDIT.

Ford ? OBD Trouble Codes
 

·
Registered
Joined
·
3,553 Posts
You better find a mechanic that knows these old IDI's.

What's your location? Maybe someone or me on here can recommend one.

If you do, have them record the codes so you can post them on here. The codes have to be relative to a diesel not a gasser.

A diesel has to have the throttle held to the floor when retrieving the codes, most mechanics don't know that and get all kinds of codes that are not relative.

Did you click on the link to see how to retrieve the codes?

You cannot retrieve the codes with a OBDII scanner, only a OBDI scanner.
 

·
Registered
Joined
·
60 Posts
On the tranny OBD1 test if you've got a decent meter (Fluke or anything with a "beep" tone for continuity) just put it in Ohm beep mode and one wire to the pin that outputs the ground pulses, the other wire to a good ground, and shorting jumper installed to initiate the test. then you can run the KOEO from the Cab and just count the beeps for codes while holding the go peddle down FYI.
 

·
Registered
Joined
·
24 Posts
Discussion Starter · #7 ·
I'm near mccomb ms. I'll be sure to stand by and see about the codes. Be sure to use obdI not II and keep it to the floor and record
 

·
Registered
Joined
·
24 Posts
Discussion Starter · #9 ·
Ok guys got it scanned and all we got were 654 and a few others similar to this which he said was tot (transmission over temp)found out the owner before installed a temp gauge incorrectly he fixed that... Bye bye OD light. Now we still have the rev issue. We have it narrowed down to an issue when it's under a load it will rev up and down but rapidly not like it's shifting just rpms going crazy but ONLY UNDER LOAD if it's straight and 60mph we are good but 65and above it comes back. You can hammer it in park and never an issue . Please help
 
1 - 9 of 9 Posts
Top