Fuel guage, 3 wires, without circuit board?

[Wincks2]

My truck has a 6.2 diesel in what was originally a gas truck.

If I get the diesel fuel guage (lmc truck and a local supplier offer a different guage for the diesel truck than the gas truck) should it work connected to only:

Wire bringing power to guage.

Wire grounding guage to chassis.

Wire from sending unit.

So the circuit board behind the cluster isn't part of the equation? I'm asking because a prior owner cut a hole in the circuit board.

2. Would any generic fuel guage work as long as it is 0 ohms at empty and 90 ohms at full, and accepts the three wires? Lmc sells different gauges for gas and diesel trucks, but I wonder if the only difference is whether they say diesel rather than unleaded fuel only on the front.

3. In case it is relevant: The wires on my sending unit are:

Wire to fuel guage.

Wire to ground.

Wire to water in fuel light (it is a 6.2 diesel in what was originally a gas truck. I still have the water in fuel sensor from a 1982 sending unit).
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[ray_mcavoy]

Originally Posted by Wincks2

If I get the diesel fuel guage (lmc truck and a local supplier offer a different guage for the diesel truck than the gas truck) should it work connected to only:

Wire bringing power to guage.

Wire grounding guage to chassis.

Wire from sending unit.

So the circuit board behind the cluster isn't part of the equation? I'm asking because a prior owner cut a hole in the circuit board.

Yes, you can wire it direct like that to bypass the damaged printed circuit. I'd recommend checking with a wiring diagram to make sure you get the wires routed to the appropriate terminals on the gauge. Or if there isn't too much missing out of the printed circuit, you could follow the traces on that.

2. Would any generic fuel guage work as long as it is 0 ohms at empty and 90 ohms at full, and accepts the three wires? Lmc sells different gauges for gas and diesel trucks, but I wonder if the only difference is whether they say diesel rather than unleaded fuel only on the front.

As far as I know, the printing on the gauge face is the only difference between the gas & diesel fuel gauges. I believe both use the same meter movement and both work with a 0-90 ohm sending unit.

3. In case it is relevant: The wires on my sending unit are:

Wire to fuel guage.

Wire to ground.

Wire to water in fuel light (it is a 6.2 diesel in what was originally a gas truck. I still have the water in fuel sensor from a 1982 sending unit).

I don't think the added wire for the water in fuel light will make any difference as far as the wiring for the fuel gauge is concerned. That's a totally separate circuit (although it might share the ground wire in common).

[Wincks2]

Thanks!

Will give it a try.
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[cdm10700]

i converted my 82 jimmy from diesel to gas an never changed sender or gauge so as far as gauges being different i dont think they are other than face

[hatzie]

Diesel or Unleaded Only markings on the gauge face are the only difference on the gauge.

Some Diesels up to 1983 had the Water In Tank indicator built into the sender. Some of them also had a line attached to a valve mounted in the forward spring mount to drain water out of the tanks.

1984 and later... The Water in Fuel sender was part of the Standayne 80 filter housing. Hopefully you didn't use one of those leaky POS.

Since your 1985 truck was originally a 5.7 gasoline engine. The wiring harness will not have provision for either system.

[Wincks2]

When I discovered the water in fuel sensor on the old sending unit, I added a fuel line to the spring to drain water. There wasn't a drain line on it when I got the truck.

Haven't connected the water in fuel wire to a light yet. Do have a wire on it in hope of doing so at some time.

Currently using the pos fuel filter you have mentioned, but the prior owner doesn't have a wire going to that water in fuel sensor either. I haven't bothered to hook that one up either.

Should do them both, but right now it is 40 below. So perhaps in the spring.

In the meantime, later today, I hope to have the fuel guage working for the first time in the three years of so I've had the truck. Ran out of fuel about 5 times the first year, then no troubles until this winter when we ran out twice. My guess is because of wax flakes clogging the lower fuel tube. The additive I used to prevent flaking was from last year, so maybe it didn't do the job.

[hatzie]

I have this Top Loading Standyne Fuel Manager from the T400 trucks. on all three diesel trucks in my fleet.
The 6.5L motor in my 76 came from a T400 truck so it already had one. The 2000 GMC is a T400.
Any 92-2002 CK 6.5L engine will have this filter assembly. The unit on my CUCV came from a U-Pull-It donor engine with a big hole in the block. I didn't pay $200 for it and mine came with the hoses brackets and wiring plugs. It replaced a good CAT assembly I liberated from a bigger salvage yard machine a few months before. The CAT was great but the Stanadyne fits in a more compact location and it matches the filters on the other two trucks so I can buy case lots.

[Wincks2]

Thanks. Have read about those glass bowl ones. Some discussions around the net say the fm100 will work on the 6.2 too.