The best way to diagnose a non-working speedometer?

[rjd2]

Hi folks-both of my Deloreans have non-working speedos. One of them intermittently worked with my reseating the plastic cap for the square drive at the spindle, but then went dead again. Is there a means by which I can systematically work my way "downstream" from the wheel and figure out where the speedo is failing? I used the search function cause I recall folks having issues with this, but couldn't find mention of a "top to bottom" assessment. Thanks.

[WHO1DMC]

Hi folks-both of my Deloreans have non-working speedos. One of them intermittently worked with my reseating the plastic cap for the square drive at the spindle, but then went dead again. Is there a means by which I can systematically work my way "downstream" from the wheel and figure out where the speedo is failing? I used the search function cause I recall folks having issues with this, but couldn't find mention of a "top to bottom" assessment. Thanks.

Are the cables still connected to the lambda service counter? I would check there first by disconnecting the end from the wheel and see if it spines. Mine was deleted by the PO so I have no idea if it works.



Dave B.

[82DMC12]

The lambda counter adds some unnecessary binding and complexity to the speedo. I would suggest removing it from the car and using a one-piece speedo cable from the angle drive (hopefully a rebuilt Smiths drive by Rob Grady) to the back of the speedometer. I bought a one piece cable from Rob earlier this year and it solved all of my speedo problems including clicking and bouncing. Highly recommend it.

[Ron]

^+1^

The Lambda counter is also a good place to start checking to see if the cable is at fault. Rather than top to bottom, divide and conquer...jack the left front up, spin the wheel and see if the cable is spinning at the counter. If so, the problem is between there and the speedometer, if it spins at the speedometer, the speedometer is bad.....

[David T]

^+1^

The Lambda counter is also a good place to start checking to see if the cable is at fault. Rather than top to bottom, divide and conquer...jack the left front up, spin the wheel and see if the cable is spinning at the counter. If so, the problem is between there and the speedometer, if it spins at the speedometer, the speedometer is bad.....

I usually start by taking the left front wheel off. Most of the time the problem is either the dust cap or the angle drive. Check the dust cap to see if the hole in the center is rounded out and no longer square. Then take the cable off the angle drive and see if it turns and you can hook a drill to the cable and see if the speedometer moves. If everything is good, lubricate it all and then next stop is the Lambda counter. If that checks out, last stop is the speedometer head itself.