I have a '95 F250 that has developed some sort of (I believe) electrical or electronic problem. I first noticed it when starting and moving off one day. The truck had a *strong* tendency to die if I did not keep the RPMs above 1000 or 1500. (The truck has a 5 spd manual transmission and unloaded I normally start out in 2nd gear.) Once I got the truck moving, I noticed that the speedometer was acting erratically. It would jump about about 5 mph for a fraction of a second and then drop back to mormal. Occasionaly, it would jump about double, triple or quadruple this amount. The jump always seems to be in discrete steps. If I'm going 70 or higher, the jump can go high enough to cause a momentary engine cutoff, apparently as a result of a built in speed limiter. Sometimes after driving anywhere from 5 minutes to over an hour, the problem goes away. Very rarely (twice in several months) it has come back. The drivability problem shows by the engine dieing at idle in neutral or with the clutch in or dieing as I let the clutch out. Ordinarily I let the clutch out and hit the gas as the engine slows. When this problem is 'on', the engine cuts out completely before I can give it any throttle. Once the truck is moving, the problem goes away until I next come to a stop.

The problem seems worse in damp or rainy weather.

This is the 5.8L gas engine on an F250 Supercab 4x4 with the 5 spd OD transmission.

OK... I'm reading this back and thinking: Speedo sensor problem. I found references to several of those when searching the archives. Is it possible that a speedo sensor problem could also cause low speed/idle pronblems too? Otherwise, are there any common points between engine controls and speedometer? I'm guessing that there may be a loose connection or bad ground that is causing this.

thanks,
hank

 

I think you should check the magnetic speed sensor in the rear diff. It's really easy to get out. Just need a 3/8 or so wrench and out it comes. I had a speedo problem with my 99 where the speedo wouldn't move until about 20mph and then it would suddenly jump up. I bought a new sensor. However, when I took out the sensor it was covered with little metal bits, so I probably could have just cleaned it and it would have been fine. Since so much is tied to the speed, I think you may be able to correct some problems. I don't think it will help the idle issue though.

TXTrailerdaddy

 

Speed sensor's are noted for this ,on another point Txtrailerdaddy
I hope you changed that rear diff fluid lately if its that dirty its
messing up your sensor ,just think whatits doing to your gears and bearings back there.
Just my $.02

Rich

 

Thanks for the suggestions.

I fooled around with this a bit this morning. I pulled the connector from the speed sensor on the rear diff. No ABS, no speedometer reading and no problem. I could let up on the clutch w/ no gas and roll off at about 200 RPM w/out killing the engine. First I tried applying dielectric grease to the connector in case it was just a bad connectoin. This made no difference. (The problem remained) So I replaced the speedo sensor itself for $20. (The fact that the dealer stocks this part tells me that it is a 'normal failure' item.) Again no difference. The speedo still jumps and the truck tends to die at idle and is difficult to move off. Well... It seems a little bit better, but I'm not sure if that's my imagination or just variability in the problem. (Today is dry and sunny - conditions that tend to make the problem go away.)



I wonder what to try next. A newsgroup poster solved a similar problem by replacing the speedo head itself. I'm not excited about trying that since I'm sure it will cost a lot more than $20. I'm also concerned about the engine control computer itself.

<sigh>

If anyone has a better suggestion, please speak up!

-hank

 

Does your 95 have a Idle air control valve in the intake ,I don't have any manuals for a 95 ,so its a dumb ? on my part but,we have had some newer engines that don't want to idle because of this part being dirty or failing.
Don't think this is tied to your speedo sensor situation though .

Rich

 

I think I had that replaced a couple of years ago. IIRC the CEL light went on or some other unrelated problem caused me to take it in to my mechanic and he dumped the codes. They said that the idle control valve or something similar had gone bad. Replacing it fixed whatever the problem was. I'm already planning on taking it in to have my mechanic dump the codes and see if that tells us anything.

thanks,
hank

 

The final answer on this was the instrument cluster. I replaced the speedo sensor on the rear differential (for $20 in parts) and that made no difference. The dealer fixed the problem by replacing the cluster. According to them, the speedo cluster was "spiking the ECU" - probably putting noise onto one of the signal lines - and that caused the problem.

Now... I need to figure out what to do about the automatic front hubs that are acting up.:-X23

<sigh>

 

Glad you got your problem solved. As far as your ESOF hubs go, Yeti will probably tell you to torch them and go manual! (Sorry, just thought I'd get this in here before Yeti could use it as ammo on me).

 

>Yeti will probably tell you to torch them and go manual!
> (Sorry, just thought I'd get this in here before Yeti could
>use it as ammo on me).

Hm....let me pull up my soap box!!

Actually, I am not all that familliar with autos, I know there are plenty of post regarding them and why they fail.
They are operated by vacuum, so check your lines and seals.
Maybe do a search for this problem, or start a new thread that pertains to the auto hubs.

I promise, I will NOT comment on how prone to failure the ESOF system is!!

 

I've done some searches and found a lot of material. Most seem to favor manual hubs and I'm considering the change over myself.

BTW, this is not an ESOF system. I have a lever on the floor (aside from the shift lever) that goes from 2HI-4HI-N-4LO. I need to come to a complete stop to engage 4WD, but once in 4HI, I can shift in and out of it as long as I don't change direction (which would disengage the hubs.)

Thanks for your comments and I do appreciate your opinion.

 

[updated:LAST EDITED ON 15-Nov-02 AT 07:28&nbsp;PM (EST)]>I've done some searches and found a lot of material. Most
>seem to favor manual hubs and I'm considering the change
>over myself.
>
>BTW, this is not an ESOF system. I have a lever on the floor
>(aside from the shift lever) that goes from 2HI-4HI-N-4LO. I
>need to come to a complete stop to engage 4WD, but once in
>4HI, I can shift in and out of it as long as I don't change
>direction (which would disengage the hubs.)
>
>Thanks for your comments and I do appreciate your opinion.

The auto hubs on your year of truck have a reputation of "blowing".They are dependant on axle rotation to lock in.The manual hubs have a better reputation for reliability.
If you decide to switch to manual hubs you can go with factory Ford or aftermarket.Warn,SuperWinch and MileMarker are some of the aftermarket names.
With the manaul hubs you can shift in and out of 4wd. at random when the hubs are locked.I usually lock them in before I leave the house if I know I'm going to use them that day.Many people leave them locked in for extended periods of time.