joejoe

Went into town to fill car and noticed it was using quite a bit more fuel. After fill up did a little math and the fuel economy had gone from 18/19 to about 10 mpg. Pondering this on the way home I noticed that the odometer would register about 1/4 mile and then stop. After a few hundred yards it would start again and 1/4 mile later stop. My usual 7 mile trip ended up at 5.2 miles.

When I got this car in July I replaced the odo gear, and it has worked perfect until now. It has been to sharktoberfest and driven locally for about 2k miles. I have the speedo out now thinking I must have missed a small part of the old gear, but it is clean.

Not sure where to look next. Any advice is greatly appreciated.

Mrmerlin

check the speedo connections in the spare tire well.
if you have the speedo out then make sure there isnt a small flash on one of the teeth of the new gear you installed,
if there is, then file it down this will cause the gear to stop turning

Opelotus

What year car?

Does the speedo also quit working when the odo stops?

joejoe

Thanks merlin have checked the connections in wheel well, and made sure there was no flash. I am not sure why would run good then start this. Sorry car is '86.5/and speedo runs as should.

joejoe

Well think I may have found problem. Upon more inspection found the plastic housing that holds the gear shaft has a crack in in. As the worm gear turns the shaft is pushed not allowing the gear to be straight. I have another speedo with 63k, and will disassemble to roll odometer to 119k that is needed for this car. Thanks for replies, and I hope this takes care of it.

Opelotus

Good find! Let us know how the swap works out.

Mrmerlin

check the new gear for flashing on one of the teeth,
this may have caused the damage you found,
use a magnifying glass

joejoe

Wellll... swapped speedo again with a 170mph one. It does not have the kilometer markings and starts at 20 mph (I canot remember where I got this one) odo worked well, but speedo seemed to register slow, so out it came also. I noticed that the circuit board is bigger than the one that was in the car (speedo goes to 160 and starts at 10)

Dug through my speedo clusters and found another from '85. Unfortunatly there is the same split in it. This speedo looks better, and the split does not look like a break, but manufactuered (it also has a smaller circuit board). Anyway pulled it apart to set mileage and installed. Seems to be o.k., but will drive a bit tomorrow to verify.

As an aside it took about 20 minutes to remove cluster (helps if you've done it a bunch, lol) and resetting odo took about 15 min each time. When I did the gear change checking for flash was the longest part merlin. As you say a good magnifying glass is needed and good light.