98 speedo drops to 0 at 115+ mph

[BlackMagik]

Hey SHOZ123....the comment about the speedo on the 98 being crap.....you know, now that you mentioned it...it is malfunctioning. I took the car out for a high speed run recently and when I eased it up to about 115mph the freakin speedo needle dropped like a rock down to zero. What gives? Is this a VSS problem or do you have any other good ideas? It only happens at 115+ so it's no biggie but it is strange!

 

[nothingtoseehere]

I believe there is a write up on this at V8SHO.com Kind of hard to get Ford to fix..."Yeah, I was running the car to ungodly speeds and the speedo crapped out" thumbs_u

 

[AutoSHO]

BlackMagik:
Hey SHOZ123....the comment about the speedo on the 98 being crap.....you know, now that you mentioned it...it is malfunctioning. I took the car out for a high speed run recently and when I eased it up to about 115mph the freakin speedo needle dropped like a rock down to zero. What gives? Is this a VSS problem or do you have any other good ideas? It only happens at 115+ so it's no biggie but it is strange!

Yes, go to http://www.v8sho.com/ , they have an article there on it. The newer cars use an ABS sensor to pick up speed, and for some reason, some of them get confused at that speed.

 

[wdnitro]

Got the same problem with mine. Happens between 110-115. Sometimes drops to 0 and sometimes drops and hangs around at 40. No fix to the problem as of yet.

 

[Diamond Jim]

From what I have been told and have been able to figure out on my own, The V8 SHO cars suffer what is best described as "sensory overload" Plainly put, the control modules are recieving input from so many different places and sending outputs to many different things, that when you reach higher speeds the speed of the processor just is not fast enough to keep up with everything. Since the speedo is considered "non critical", in oder to free up resources for other critical devices, it simply drops the speedo.

Jim
'93 MTX

 

[SHOZ123]

It's only the '98s. The SHO uses the ABS brain to run the speedo as stated. My theory is the changed the ABS brain in '98 and the way they fixed it was to drop the SARC suspension in '99. This also uses the speedo signal. Data transfer collisions.

 

[SHOZ123]

Just thinking. Try pulling the SARC fuse and see if the speed still falls out.

 

[pete c]

The ABS sensor is a magnetic switch. That magnetic switch can open and close just so many times a second. Apparently at 115 it can no longer keep up.

Atleast you got an excuse when the cop busts you at 130. "Sorry officer, I didn't realize I was going that fast, the speedo ***** the bed at a buck fifteen."

 

[wdnitro]

Still fails if you pull the SARC fuse. I've done a run with it on and off. Doen't really concern me that much. One of those things I can live without.