1991.5 FSM

[Arville]

Hey, Fellas. First post here...Wondering which factory service manual to purchase for my 91.5. Should I just get the 92 book? I heard somewhere that you can get some kind of supplement to the 91 manual that covers the changes, but aren't the 91.5 trucks and the 92's essentially the same?

[cummins king]

91.5 and 92 are almost the exact same

[Arville]

Does the 91.5 have the crank sensor and wire for a tach?

[Arville]

So, a 92 service manual would be sufficient? Does the 91.5 have the crank sensor and tach plug like the 92's?

[cummins king]

92 will be good i thought that it was just the 92s and 93 s that had the tach sensor, but im not 100% sure

[CumminsPride]

Some of the early 92's didn't even have the tach plug. 91.5's do not have them and they should have the early voltage reg on the firewall as well as no crank sensor.

[PToombs]

Get one for a '93. It has the Getrag repair section in it. This might come in handy someday.
Most of the wiring is the same from '89 up. I have used my 93 manual to help guys with older trucks, no difference.