I can't drive 55!

[Poppy01]

Originally Posted by WyoFree

Hi Judy and welcome to the forum.

One thing you may want to check is the Cummins computer diagnostic center. My coach has a Detroit Diesel but all coaches from around lets say 1989 on have a computer with built in diagnostics that will tell you (or should tell you) where the problem is?

Some will tell you by blinks you have to count but on your 98 it should produce an actual code. Look up that code in your manual and it should tell you where to look.

Harry

Fyi, there a lot of DPs built after 1989 with purely mechanical engines. I have a 1994 with a mechanical diesel. The only thing that needs electricity to operate (on the engine) is the fuel shutoff solenoid. The tranny is a different animal, but you won't find any diagnostics from the engine.

[NHRA225]

Call Spartan Chassis with your Serial Numbers. They Installed your gauges and the sensor . They will assist you with the simple trouble shooting process - Unless your all ready at a Spartan Chassis shop !
Cummins did your Engine and Spartan did your Chassis.

[Judy Harris]

I think this is the route to take. The Cummins shop was great for other issues but their AC repair was down and they admitted that they dont work on them much. And, the dang spedo worked the next trip out, so we'll see.

[OLYLEN]

To get by use a GPS if you have one, you will want one. If you have smart phones, free GPS app GPS Speedo. Also then can relate RPM in top gear to speed. If you can find the sensors a wiggle on the wires to reconnect might work also the connection to the Speedo itself.

LEN

[JFXG]

Judy.....
as others have said, it should be an easy fix. In the meantime, there are myriad ways to estimate your speed. On small/local streets go a bit slower than you think is right. It's misleading to judge low speeds in a large vehicle, particularly if you're not accustomed.
On the highway:

GPS

Tach- in most DPs top gear and 1600-1800 rpm will put you somewhere about 60 mph.

Mile Markers- 1 every 60 seconds; in some states there are smaller signs showing every tenth of a mile-- one every 6 seconds.

Lane stripes- stripes are 10 ft, gaps are 30 ft. Two stripes/sec will give you 55 mph.

There are more, but that'll do. Have fun!