Intro and Some Questions

[mach5]

Hello all,

My name is Josh and I live in Oregon. I'm new to this site and have a couple questions.

I've recently purchased a '92 Ford F350 Crew Cab. It is a diesel with a Banks Sidewinder turbo setup and automatic transmission. It has 175,000 mi and is a great runner. It has a trans temp and pyrometer gauges on the pillar. I've recently performed a maintenance including fuel filter, oil change/filter, also replaced all return fuel lines, and O-rings.

Shortly after I bought the truck, the tachometer stopped working. I checked the fuse, as well as checked all wiring and cannot see any obvious problems. Any idea what I should check next to troubleshoot the tach? Also, what is an acceptable operating temperature for the transmission? I am seeing 180^ pulling a heavy load.

This is my first Ford diesel and I'm a newb. [img]/ubbthreads/images/graemlins/smirk.gif[/img] Any help is appreciated.

Thanks in advance.

[fordguy09]

I have the same problem with my tach, it sucks and my fuel gauge skips around all day.

[Bill1013]

Check the wires on the tach sensor next to the oil fill cap, mine are bare and just about ready to break. The tranny temp can be as high as 250F* for a short while, if you are only running 180F* your tranny temp is prolly only about 20F* higher, 220F* is normal.

[cdnsarguy]

Fordguy.....your fuel guage would most likely be a bad sender in the tank if not a bad wire connection.


A dead tach sender should/would send the automatic trans into a "failure management mode" (limp mode) with harsh engagements and firm shift feel and an abnormal shift schedule. It has no effect on a manual trans only the Tach readings.

Check the wires where they exit the big nut on the oil filler housing , known to short out due to bare wire.....

Replace the tach sender on the oil fill housing a big 1" nut with 2 wires. Ford only part Engine RPM sensor E5TZ-17B384-A about $50. You can remove and clean it but usually changed later too.

You can test it too, hold it in the air away from ferrous metal, using an ohm meter lead on each wire you need DC resistance between 2000-3000 ohms.