diesel conversion wiring help please

The place to discuss problems and routine maintenance questions and tips. This is for topics that are specifically diesel-related.
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Joined: Wed Feb 10, 2010 10:15 pm
Location: Hutchinson MN
Isuzu vehicle(s): spacecab diesel Holden rodeo 1993, 1986 pup spacecab, 1987 pup spacecab

diesel conversion wiring help please

Postby downunderyank » Fri Jun 01, 2018 8:44 pm

Hey guys, I'm doing another diesel swap in an 86 spacecab after many years since the last one and I'm attempting to use the gas harness and just use a pushbutton and 10.5v GP's. I can figure out the glow plugs and the stop solenoid but I've completely forgotten how to wire up the alternator. The pup had a 2.3 gas with what appears to be an internally regulated alternator (I don't see an external regulator). Diesel is out of an 86 trooper so has the square plug and one thick black wire. Does anyone have a similar setup they could take some pictures of? Thanks!
converted '86 diesel spacecab

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Posts: 119
Joined: Wed Mar 10, 2010 8:25 am
Location: Liberty, TN
Isuzu vehicle(s): 91 diesel conversion, 1986 4x4 pup diesel

Re: diesel conversion wiring help please

Postby heathw » Tue Jun 05, 2018 9:28 pm

It should be 3 wires in that harness. One is obvious because it was the largest(from what I remember). The other 2 I cranked the truck and got 12V from the alternator but 0V fro the harness. Connect it. The other I got 12V from the harness and 0V from the alternator. Connect it. (you will know if you get it wrong because you can not cut the engine off with a key. lol The 12V will backfeed to the IP).
91 Isuzu p/u Converted to diesel
86 4X4 Pup diesel