my speedo is going crazy!!

[Blackgeetee]

Okay guys, figure this one out.

A couple weeks ago I was driving and all the sudden my speedometer quit working. Then after about five minutes it started working again when I was going down the interstate. It worked fine for awhile up until last night. It quit working again. So today I reset my computer to see if it would help. It didn't. I went for a drive and about five minutes later it zoomed from 0-65mph in less than a second lol as it started working again. So now it's fine again. What do you guys think the problem is? Is it computer related, I do have a custom chip that was burnt last spring. Or is it a mechanical problem? Any feedback would be nice. Anybody else ever have this problem?:beer:

 

[Blackgeetee]

No ideas eh?:shrug:

 

[GR8WHITE]

I don't remember if you had a gear change or not. It could be the plastic speedo gear in the tranny, or maybe the VSS wires that connect into the tranny could be grounding on something. That one is weird, unless you've been under there lately. It might also be the "speedo calibration box" either going bad or grounding out if you have added one. It could also be a bad positive, switch or ground connection if you have added one also. It does sound electrical, but like I said I don't remember if you added a gear.

 

[Blackgeetee]

Thanks Don!

No I never did change the gear, still have the stock 3.27's. The speedo is working fine again now. Those pesky wiring problems can be a pain to find. Hopefully it continues to work.

Thanks again:beer:

 

[Blown306]

I'm not really sure about this and it might not even apply but I'll throw it out there anyway. Kinda had the same problem on my F250...cruising along at 75mph then all of a sudden the cruise control went off, ABS light flashed and the speedo went crazy. When driving it to the dealer, the speedo quit completely and the trans was stuck in first (good thing it was only a block away). Turns out it was the ABS sensor causing all the havoc...

 

[GR8WHITE]

Couldn't remember if you'd done the gear or not. Still it does sound electrical. Sounds like maybe Blown306 hit it on the head. You get it buttoned up?

 

[Blackgeetee]

Thanks again for all the help guys but it's been working fine for the past week now. If it happens again I'm going to hook it up to Steve's laptop and see if the computer says anything.

 

[CobraCallie]

ya know.. my friend back in Dallas has the same problem with her '98 mustang.. but I've never had a problem with my cobra..

her thing will get stuck at around 60.. and then when it lowers it won't stop at 0 but it'll go past 0 and go back to 120...

 

[Blackgeetee]

Originally posted by CobraCallie
ya know.. my friend back in Dallas has the same problem with her '98 mustang.. but I've never had a problem with my cobra..

her thing will get stuck at around 60.. and then when it lowers it won't stop at 0 but it'll go past 0 and go back to 120...

That's kind of weird. Mine won't do that because there's a little peg the speedo needle rests at 0.

 

[CobraCallie]

yeah but I guess her peg is short or something.. cause she says it goes right past the 0.

I told her to give my brother a call up at Dallas Mustang and he'd come over and check it out. I never heard about it again.. so I never found out what the problem was.

 

[IUP99snake]

I was driving my mom's outback on the highway at around 70MPH, and the instruments went crazy like that. It turns out that the alternator was going bad, and wouldnt charge the battery over 3500RPM's (the outbacks are geared real lowwww)
Cruising under 60MPH would keep the rpm's low enough that the alternator would charge the battery.

-Homer