1998 int 9100 wont go over 1500rpm speedo no read until 50mph help

Beat that horse!, When my speedo went it was very similar.
The reason you can't go over 1500 RPM is due to the ECM wanting (in my case) both sensors.

The Celect Plus ECM has in the features something like " If no speedo signal derate to ???? RPM"

After I changed both sensors - couple years ago- I still occasionally get a derate to 1500 RPM.

This past week I hooked up Insite and set that parameter from 1500 to 2100.

Haven't gone anywhere yet to test, but thinking that may be the issue.

I crawled under and looked at mine today, if you do not get your head above the drive shaft you cannot see the top sensor - the wires come in from the other side also.

The horse is DEAD!