I learned something the other day about the electronic speedometer and tach used in the 90's medium duty trucks. A guy on the IDI Facebook page posted a picture and said the needles made a full sweep when you first turned the key to "on". He said the tach had about 5 little switches on the back that changed the calibrator different vehicle applications and there was a sticker with a chart showing how to set the switches. He said the speedometer had switches on the back also, but no chart to explain the settings. (Maybe for different gear ratios or tire sizes???) not that it helps us pickup guys that much, but he said his 3500 rpm tach got its signal from the flywheel teeth which he remembered to be 128 teeth on his 12 valve Cummins.

 

 

I wanted to update this thread with some pictures and info of a tach type not yet covered: a closed style (non-integrated circuit) 4500 rpm gas engine tach. Only the later style has been detailed so far. It came from a 1986 F700, so I expected it to be integral circuit, but it wasn't. The engineering number is E0TF-17360-Y (cast into the plastic) and BA stamped in ink next to it. Just below the cast numbers is F191 (also in ink). The face of the tach has the engineering number E0TF-17B316-B.







I removed the rear cover and unmounted the circuit board for cleaning. Then I painted the gauge needles and the cluster is now ready to try out in my 1981 F150 straight six.

 

Looks good! May I use your pics on my web site?

 

Absolutely Gary, it's always an honor to have my photos published on the Garagemahal

 

Ok, go take a look now: Tachometers - ???Gary's Garagemahal. I sorted the pictures out a bit using the "tab" feature.

 

That looks GREAT Gary! I really like the tabs. It is so much more organized than a maze of linked pages or endless scrolling. You have done such a nice job of making the information accessible

 

Thanks! I enjoy doing it. And comments like yours, or the one I got recently via email, add to the enjoyment.

 

I know this thread is old but i've been looking for info and coming up dry. Does anyone have a bench testing solution for the 85/86 diesel tachometer from the F250/F350 trucks? The gassers are easy. I have a HEI and a drill with oil pump drive set up to test those.