6.2 diesel to gas engine.

[custodian]

I bought an 85 SWB with an AT and 6.2 diesel and will be switching to a 350 gas. I'll be replacing the gas tanks. Will the wiring harness have to be replaced? Anything else that will need replacing? ETC?

 

[1987 GMC Jimmy]

I’m assuming this is going to a run of the mill carb, HEI setup? No fancy EFI, TBI, etc.?

 

[custodian]

Yes, Carb and HEI. Nothing fancy. Giving this truck to my youngest granddaughter.

 

[Rickf]

Should be able to adapt the 6.2 harness to gas. Injector pump wire will power the HEI, water temp sender may need extending, if the carb has an electric choke you'll need to supply a switched & fused 12 volts. Won't need glow plug wires.

 

[bucket]

Should be able to adapt the 6.2 harness to gas. Injector pump wire will power the HEI, water temp sender may need extending, if the carb has an electric choke you'll need to supply a switched & fused 12 volts. Won't need glow plug wires.

This sounds right. I've been told a few times that the harness is roughly the same, just different lengths on some connections.

 

[Dmack]

Mine has the conversion before my son bought it. Hope you do a cleaner job. They had pulled the ignition switch off the column, then drilled two toggle switches in the dash for ignition on and starter engage. The harness was butchered. I swapped in a factory harness.

 

[custodian]

Thanks. Sounds very straight forward. Will not cut any wires.

 

[K5ride]

I deleted my post due to misinformation.

 

[Blue Ox]

The 6.2L is not the Olds diesel. I has Chevy bolt patterns.

 

[Hondo78]

This sounds right. I've been told a few times that the harness is roughly the same, just different lengths on some connections.

The 6.2 tanks should work fine with a carb I'm sure the diesels don't have a fuel -pump in them.

 

[Blue Ox]

You'd probably do well to change the pickups if you have evap. Also, the screens on diesel pickups are different. Don't know if that would cause a problem, but they have a relief valve that gassers don't.

 

[K5ride]

@ Blue Ox......... OOPS...... your right. After seeing your post, I looked it up and it was the 5.7 diesels that were made by Olds. I guess my memory isn't as good as it used to be....LOL.

 

[Hondo78]

K5Ride

Easy mistake: The 5.7d and 6.2d Diesels were originally great engines for the time, however back then GM had a planned obsolescence plan that cheapened the original concept. A former neighbor now 90 years young, had both his original Oldsmobile 5.7 diesel wagon and a GMC 6.2 diesel step-side half ton, till he stopped driving last year. He was an Oldsmobile engineer on the diesel program.

 

[custodian]

Any tips on starting a diesel that has been sitting for along time? Going to see if it runs before I take it out.

 

[Blue Ox]

Is it in the truck?