99 MCI 102DL3 Speedometer Questions

[Matt Crowder]

The PO of our 102DL3 removed (and somehow lost) the speedometer sensor and bracket when replacing the drivers drum.

I tracked down the bracket and magnetic sensor, installed the 4x 1/4-20 bolts at 90 degree separation in the drum, and set the gap on the sensor. The speedometer now moves, but it and the odometer are about 50% low.

From reading other posts on here, I recall that the dip switches on the back of the speedometer are for the odometer and the set screw adjustment is for the speedometer. Unfortunately, even at the extreme on the set screw, the speedometer is still off by at least 15%.

I also haven't been able to find any documentation on what the dip switches should be set at. We are using 315/80R22.5 tires that are 481 rev/mile.

I thought about doubling the number of bolts on the drum from 4 to 8, but the speedometer and sensor are both the correct MCI parts for which the manual states 4 bolts is correct.

Does anyone have any thoughts on fixing this? I guess it's possible the speedometer is just bad.
Does the gap adjustment on the sensor alter the reported speed?

Thanks!

[Gary Hatt - Publisher BCM]

For what it's worth, I never look at the speedo on my Eagle bus dash. I monitor it on my Garmin GPS as it is digital and easier to see.  I also reset my Trip 2 Odometer on my GPS every time I fuel up, as my gas gauge also does not work.

[luvrbus]

Install a digital speedometer there are 2 cavities'  on the  ECM for those  E-2 and E-3 if you have the series 60 Detroit

[Matt Crowder]

Just wanted to follow up with the solution in the event anyone else runs into this.

I think there is a typo in the maintenance manuals I have. The maintenance manual says the Dixon speedometer is supposed to have 4x bolts. It says the same thing for the alternate Sigmanetics. Given that information, I had initially installed 4x 1/4-20 bolts which was giving me about 1/2 the expected speed.

After looking closer, I noticed that while the maintenance book says 4x bolts, the parts book actually lists 8x 1/4-20 bolts for the installation. Once I verified the front wheel speed sensor wasn't used for anything else like tag steering (it's speed switch is tied to the transmission / road speed generator), I decided to give it a try.

Sure enough, after changing to 8x bolts both the speedometer and odometer were pretty much spot on accurate.