Hey everybody, well recently my speedo started jumping. It jumps between 10-15 mph diffence. Now what I have found different than archived posts regarding the abs light is that instead of others having the light on all the time my abs light doesn't come on till the speedo starts jumping around the 75-80 mph range then it stays on. I have recently replaced my spider gears and rear diff fluid. Any ideas if these two could be related? I think my speedo is electronic (93 ford bronco, e4od) so i don't have a problem with the cable. I no of a sensor on the top of the 8.8 which i'll check out tomorrow but the light is always on. Any ideas?

Gabe

 

The sensor on top of your 8.8 is the abs sensor, that might cause the light to be on.
Don't know about electronic speedos, but on mechanical speedos, when the needle jumps or vibrates all the time you are moving, it was usually a lack of grease in the cable.

 

Ive found over the past few days the abs light only comes on when the speedo is jumping around the 75-80mph range. I can drive all day on city streets and it will never come on... but once i get on that freeway it lights up. Is this still a sensor problem?

Gabe

 

Mine is doing the same thing. Of course this had to start on Christmas Eve night just before we left on our 1500 mile cross country holiday odyssey and 30 minutes after every auto parts store closed. (Cruise control doesn't work too well when it thinks the truck is doing 75...then 60...now 80....back to 70...) I pulled the sensor and it looked like some bit of crud had come around and dented the bottom side.

I really don't know why that should be, I had the entire rear end apart and cleaned about a year ago to fix damage from when the original plastic bodied sensor fell apart and dropped into the rear end. (Another not-too-fun experience)

Anyway, if you hold out 'till tonight, my sensor should be in and I will let you know if it "did the trick" Or if you have the original plastic body sensor, you may want to go ahead and up-grade it to a metal one to avoid the sort of gear-crunching experience I had.

 

its probably your vehical speen sensor not sure about the 93s but its either located on the front of the tranny or the top of the rear end on the same side as fill plug but on the top.

 

just wondering why you pick 4xfordbronco i picked 4x cause im on my 4th

 

I'll check out that VSS also. I picked 4xfordbronc because instead of 4x4 its 4xford (some of my friends while I was in college which I just graduated from) all had broncos, one explorer and one ford ranger. One of my friends then made a sticker that said 4xford wheelin. Thanks for the help.

Gabe

THats my story and I'm sticking to it...

 

Well, after laying on the ice in the balmy 10F air and changing out the sensor, my speedo is still bouncing. Dunno what the problem is. Like you said, it doesn't (appear) to do it below about 55MPH (at least in my case). Then when you get up to 55+ it starts snapping back and forth +/- 10 MPH or so.

I'm stumped for the time being It was working fine, then it just started out of the blue. If I come across anything I'll post back. Let me know if you find the cause, too!

 

hey corey I'm going to try to pickup a vss unit tomorrow and try that out. Then I'll get back to you.


Gabe

 

Well, I bought a new vehicle speed sensor for the rear diff and it was like 25 bucks from ford. I installed and no luck. My speedometer starts to jump around 50 and my ABS light comes on around 70. I see some pretty wild jumps. Like from 70 to 45 back to 70. I also checked the two connectors on each front wheel and the connections in the engine compartment were attached. I'm not sure what is up. Hows it coming along with you?

Gabe

 

I think the was a TSB about high speed needle bouncing. Had to do with the amount of space between the vehicle speed sensor and the toothed ring on the carrier. As the vehicle gets older the bearings wear causing the ring to run a little untrue. Some times the ring would be closer to the sensor on one end and farther on the other. It would cause the sensor not to pick up a signal in spots and then the needle would bounce. If it was bad enough I think there was a software update to counteract the problem. I'll see if I can find the TSB number on Monday.

 

I went to alldata.com and punched up the TSB list on my '93...it's a bit long to post here, but the link is:

http://alldata.com/TSB/20/93200102.html

Anyone else can go in the front door and check TSB's for any vehicle. But this list for the '93 describes about every leak, squeak, squeal, vibration, break down, blow up, burn out, fire, failure, freeze up, or other nightmare repair I have had on my Bronco. Item #122 mentioned something about speedo recalibration.

I suppose this bearing issue means that the rear-end is due for it's two-year tear down / rebuild maintenance interval

 

number 61 talks about the Speedometer/Odometer - (Programmable) Pointer Waiver. Maybe they had an update for the ECU. TSB number62111

Gabe

 

bump

gabe