Hi guys im new to this site and hoping you can help me. I have a 93 f-250 with a 7.3 diesel in it. The O/D light is flasing had it on a scanner showed the speed sensor was bad, put one in it went away for awile then came back. So then i decied to put a t.p.s. on it went away for awile then came back. The Trans has has about 5000 miles on it since a complete rebuild. I also checked voltage at t.p.s and at idle it was 1.3v and at w.o.t. it was at 4.0v. All connections look fine also. It seems like that when the temp outside gets cooler it starts to do it then it does it for awile. When you start it and take off it dont start blinking until you stop for the first time and take off and hit 2nd or 3rd gear. I dont know what else to do and really need to fix it any help will be well apperciated. Thanks in advance

 

4D3,
Welcome to FTE and the IDI diesel forum.

I can't help you at all on the automatic, but there will be someone along shortly that can.

Just from the fact it seems to be temp related, I am going to guess a bad connection on the speed sensor.

 

You Said Its When You Come To A Stop It Starts Flashing. I Would Look Into A Tach Sensor Unit On The Ip Gear Housing Where You Put The Oil In At. Mine When Its In Gear Will Not Flash Untill I Make The First Stop, Then It Will Start Flashing. It Doesn't Do It All The Time And Only Happens On Lower Rpms. The Tcm Requires A Good Tach Signal Or It Will Throw A Code. If You Have A Tach On The Dash, Does It Work At All Rpm And Work Smothly? If Not, Then That Is Definatly Your Problem. It Can Also Put Out A Weak Signal That Appears Good On The Tach But Not Acceptiable For The Tcm. Good Luck..

I Can't Get My Computer Not To Type In Lower Case, Just Caps If Anyone Was Wondering.

 

Yes it does it when i make the first stop. It does have a tach and seems to work fine. Is there any way to test this and could you explain more of where the tach sensor is located, im kinda new to diesels. Thanks for the info!!!

 

Location of tach sensor:

(from Dave Sponaugle's gallery)

 

Thanks for the pic, thats looks easy enough to change is there any way to test these to see if they have a week signal or not. Also can you pick these up at any parts store.

 

I think its a ford dealer only part, but it would cost you nothing to phone around.

 

I haven't got a part number for it yet for mine and have not priced one at ford. Since your tach works, Im not 100% sure if thats your problem but its something I personally would replace since you replaced the other sensors. If its a week or broken up signal, the tach may appear ok visually be not be good for the tcm. No garentee that it will fix it but you can try.
Im not sure if its the same way for this sensor as for a speed sensor on a mack, but I screw them all the way in till it stops, then back it out 1/2 a turn and tighten the nut down snug, not tight!!! You may want to check and see if it is adjusted properly. If its not in far enough, it will give a bad reading. When you check it, Pull it all the way out and wipe the end off. These sensors have a magnet which will hold pices of metal and if enough metal is on the end of it, it will throw it off as well. These are just some sugestions so don't depend on just these to fix it.
You say the light is still flashing when you come to a first stop. stay stoped and read the code and what flash code do you get? Good luck.

 

I would recheck for other codes since you have already changed sveral items. Also your TPS sensor voltage may be a bit off at 1.3 at idle. If your happy with the shifts don't adjust it, but I found best performance at 1.1 idle, and I get about 3.9 wide open.

 

Ok guys i just pulled some codes off of it and i got a code 67 and also 2-3 shift error. i am not to sure what these mean though.

 

Code 67 might be from the AC or defrost being on during the test. The climate controls should all be turned off and thorttle set to full for the test (engine off, key on).

The 2-3 code (code 59)......hmm that could mean slipping.

How does the shift feel when it shifts from second to third? Hard or soft? How about at full power?

how many miles are on this transmission?

When did this problem first start?

 

It started last winter for a while but went away so i fogot about it until it just stared again. It only between 7,000 to 10,000 on a complete rebuild. The shifts are firm and it dont seem to be slipping at all

 

Have you tried checking the bulkhead connector for signs of corrosion or crud?

 

Is the bulkhead connector the big one on the side of transmission?

 

The bulkhead connector is what plugs the solenoid body into the wiring harness. Its a grey connector on the passenger side behind a heat shield (its the only electrical connector on that side of the tranny).

To disconnect it, you first have to remove the heat shield. Then you will see the plug. To disconnect it, there is a central thumb tab that you have to push in while gently pulling up on the wires. Do not use a screw driver. It is a very stupid design and the plastic is prone to breaking.

What you are looking for is any signs of corrosion or crud inside the connector. Some electrical grease is a good idea when you reinstall it.