Speedo quit working

[Super Gnat]

My speedometer and odometer stopped working. Scanmaster shows error code 24, which is the speedometer sensor circuit.

When it happened, the needle got very jumpy then i thought i heard something fall either behind the dash or under the car.

Does anyone know if there is a write up somewhere on troubleshootin g this or what i should look at first? I have the service manuals for my car but sometimes they get hard to decipher.

Thought i would check here if its something simple that i can do before i take it to a mechanic.

Thanks.

[Steve Wood]

cable is broken somewhere between the tranny and the speedometer

[Super Gnat]

Thanks Steve.

[SuperSix]

Yep - It got jumpy because it was binding, and finally snapped. You can buy a new, one piece unit on NOS4GN.

http://www.nos4gn.com/servlet/the-234/Buick-Grand-National-GNX/Detail



Rock Auto has some lower priced options too.
http://www.rockauto.com/catalog/raframecatalog.php?carcode=1020957&parttype=1440

[Super Gnat]

My current cable is the two piece. If i get a one piece replacement, what happens to the knuckle where the cables meet and a third cable comes out? I have a GNX style dash. Originally it was digital.

[earlbrown]

You'll probably have to relocate the knuckle to the side of the trans (if the threads match that is). Otherwise you'll have to find out which side broke and try to source one/both of those.


As A test, take the T out and hook a drill to the cable that runs in the firewall. Spinning in reverse should make the needle move if the top one is good.

[tb3]

aha!  so thats the story with the 2 piece speedo cables???
they where for the digi option?
I have seen many many original analog speedo equipped dashes with the 2 piece cables just connected together

[earlbrown]

I believe it was for assembly reasons.   When you marry the body to the chassis, both the cables are right there.

  My analog car came with a 2pc and I'm still getting used to not having a bouncy needle (and a working cruise control) after putting in a new one piece.

[SuperSix]

I believe it was for assembly reasons.   When you marry the body to the chassis, both the cables are right there.

  My analog car came with a 2pc and I'm still getting used to not having a bouncy needle (and a working cruise control) after putting in a new one piece.

Correct - it was for ease of assembly.

[Steve Wood]

I have never been able to separate the two cables at the joint without fear that I would end up breaking the "joint" so I will definitely go to a one piece cable if mine ever acts up.

I just replaced the cable in my Challenger.  It failed because I was not running an aftermarket fuel management system, or because it was hanging down in front of an open header when I broke the new cam in.....

[daveismissing]

What were you not running? FAST or MegaSquirt?

[Steve Wood]

MoTeC with Megasquirt as back up

That way, when timing retard is incurred, I don't have to take my foot off the gas because I have back up

[earlbrown]

How's it feel to go faster than 100 in the 1/4mile?   I'm still running a stock ECM/translator.


Amazon has the cheapest delco 1pc I could find.

http://www.amazon.com/ACDelco-88959481-Speedometer-Cable/dp/B000C9QRCY/ref=pd_ys_iyr2

[Steve Wood]

I don't know...I did go 102 in the 1/8 on an old tw chip

[Super Gnat]

I ordered the one piece. Ill post some pics of the install. Hopefully its straightforwar d. I can get behind my dash and all that but where is the other end connected on the transmission or whats the easiest way to get to it?