I just finished getting the oil pressure gauge working on the Montero diesel. I used the stock '87 Montero 2.6 gas oil pressure gauge unit (NAPA Echlin OP6087) with a 1/8" NPT Female to 1/4" NPT Male bushing. The Ford Ranger diesel engine had an oil pressure switch in it that is 1/4" NPT instead of the Montero's 1/8" NPT. So here's my gauge configuration:

Speedometer - stock gas. This just worked since it was already hooked up and I reused the stock gas manual transmission.

Tachometer - I bought a Dakota Diesel DSL-1D Tach converter and hooked it up to the Hall effect sensor off of the diesel injection pump and hooked it to the stock gas tachometer on the Montero.

Fuel - I reused the stock gas Montero tank and sender. This just worked once I hooked it up.

Voltage - I used the stock Montero Gas alternator wiring harness on a Montero 3.0 V6 gas alternator. (shares the same harness with the 2.6 gas motor) When I hooked it up, the voltmeter worked.

Temperature - I used the stock temp sender that was in the Ford Ranger diesel. It has two blades so I hooked the wire for the Montero temp gauge to one of the blades of the sender. This worked but I think the gauge and sender don't match for calibration. It looks like the truck is running hot on the gauge but it's at 190*F. which is normal operating temp for the Ford Ranger diesel engine. I may see if I can use the stock Montero temp sender with a bushing adapter so it will screw into threads in the diesel engine and hopefully read in the middle? What is normal operating temp for a 2.6 gas motor?

I need to figure out how to wire the EGR light in the gauge cluster so it's not always on, rewire my glow plugs to a relay, install the straight exhaust and replace the clutch master and slave cylinders. (they are weak from sitting)

-Pmontero