91 International 4700 wiring diagrams?

[KevinF]

Hey all,

I have a 91 international 4700. The truck originally had a dt360 but a 466 was swapped in. I believe the 466 was a slightly earlier engine.

I have two current minor issues that I'd like to sort out, but I'd like to have access to good wiring information (IE complete wiring diagrams) because I am planning to swap a different body onto this chassis soon.

1) The tach doesn't work. The tach is electronic, not mechanical. I'm not sure if the 466 is using the alternator from the 360 or the 466. I am guessing that the tach should get signal from the alternator, but I am not 100% sure?

2) There is an electric pump under the master cylinder. It has been explained to me that this pump should be humming when the key is on and the engine is not running, to provide brake pressure should the engine die. Currently the little pump runs all the time with the battery connected (truck has a master cutoff so it doesn't kill the batts).

 

[GregsHD]

Can't help with a wiring diagram but I can help with your two problems. The electronic tach gets it's signal from a speed sensor in the flywheel housing, the early 466's i've seen with rotary injection pump usually have a mechanical tach. The hydroboost has a pressure switch in the system (usually on top of the unit, old style had 1 wire with push on connector, newer style has 2 wires with a weather proof plug) that activates the relay and turns the motor on. I'd check the pressure switch out first.

 

[KevinF]

Thanks, I had another gentleman tell me about the flywheel tach sensor. I measured the resistance across the terminals and got 660ohm. I will pull the sensor and check it out.

I will also check that switch out. I have a brake pressure warning light on the dash so there is an indicator that pressure switch might be the culprit.