Fuel sender wiring connection

[isaac_alaska]

Fuel gauge stays pegged at full, i pulled the cover off in the bed and took a look, there is one wire connected to the sender which goes to the frame, and another wire that probably used to go to the sender which is taped over. I'm not sure why it was disconnected or where it reconnects to. Is this even the sender that's supposed to be installed?

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[just me]

That is not a 'sender'. That is the fuel guage. To keep from damaging your guage, ground the sender wire. It will go to empty on the guage.
My experience with the sender's sold by the MV suppliers is that they are junk. They do not have long enough arms for the float to touch the top and bottom of the tank. The floats are junk and sink in a year. I used a fully adjustable aftermarket sender and am much happier. It is the same ohm as pre 64 GM. 0=empty and 30=Full.

[isaac_alaska]

Where is the sender located?

[Cal_Gary]

The fuel sender descends down from the top of the fuel tank.
Gary

[w30bob]

Hi Isaac,

Well...........I have to admit..........I've never seen "that" before. If you have an original M37 fuel tank there are two holes in the top of the tank, a big hole and a smaller hole. The sender goes in the smaller hole, the pickup tube and vent line attach to a plate that goes in the larger hole. It looks like what you have there is a fuel gauge that someone mounted into the top of a sending unit........or some kind of composite gauge/sender from something else. The M37 sender has a single Douglas connector that connects to the wiring harness, or a single Packard connector for the later B1's, and is grounded by being in contact with the fuel tank (which is grounded to the frame). It's basically a variable resistor that changes resistance as the float moves up and down, which in turn changes the voltage which is read by the fuel gauge in the dash (which is acting like a voltmeter).

I have to agree with Just....the repop senders are junk, from what I've seen. What you can do is get a good used sender from an M38 or M38A1 (depending on which type of connector you need) and modify it by lengthening the part that sits in the tank. That will give the arm that holds the float enough "swing" to go from the bottom of the tank to the top. The other option is to get an older original brass float and use it with a new repop sender.

regards,
bob

[isaac_alaska]

This must be the new repro junk sender?

http://m.ebay.com/itm/M38A1-M38A2-JEEP- ... nav=SEARCH

If it's just the float that goes bad, it looks like it would be easy to cut the end off the plastic float and glue a cork inside it. Protection of plastic, floaty ability of cork

There's another available that says it fits M37, looks the same though but probably just a stock picture. For $44 bucks I think I'll order one.

[just me]

Don't waste your money. Just order a sender from Summit or Jeg's and get one that will work correctly and has a warranty.

[isaac_alaska]

JustMe,

Would you post a link to the one you used? The ones I see have no specs listed other than length, it's a tube style so there's no arm to swing, seems ideal if the resistance is right and I can measure the depth of the tank for length.

[Carter]

What you have is a tank from a 3/4 ton generator trailer. The tanks are almost the same size and the only other differences are the gauge you have on top of your tank and it lacking two holes for the sender and for the fuel pick-up. Had one like yours once but sold it.

[just me]

What I used.
http://m.ebay.com/itm/GM-Fuel-level-sen ... nav=SEARCH

I'll try and post a pic of the setup and the worthless ones they are selling as m series replacements. This site is difficult to post on from a smartphone. ( I have no computer ) I can post on the Facebook page easily.

[just me]

The ones they sell in your link are m38 and not m37. The m37 sender moves 8" and the M38 sender only travels 4.5"

[isaac_alaska]

Thanks! Just what I needed. Got one on the way I'll sacrifice some originality for some functionality any day of the week, especially on this truck. I've been daily driving it in and out of town and getting smoother in it every day.

[just me]

Depending on your tank, you may find the hole in the tank is a tad small to fit the sender. I opened mine up about a 16th of an inch using a conduit hole punch and it all fit easily. (And no sparking to cause issues.)
I've posted pics in the m43/m37 Facebook group.

[isaac_alaska]

it looks like the correct sender for my truck is 10-60 ohm? with the float maxed (30 ohm) it's reading a bit under half tank, and with the float bottomed the needle sits on the left horizon.

it did fit though, i just filed the hole a little bigger where i needed clearance, with a magnetic file to keep extra filings out of the tank. now i just have to find the same thing but with the resistance range i need. or i wonder if someone swapped out my dash gauge for something different?

I'd be pretty close if i just put a 15 ohm or so resistor in line with the sensor wire.

i'll also check and make sure the panel gauge is grounded well. and that it has good power to it

[isaac_alaska]

the gauge i have is marked on the face

MS 24544-2
MFR. - 09527
Faria Corp

but so far i haven't found what sender is supposed to go to it. i checked the gauge wires, they seem to be making contact but i will verify for sure tomorrow. it was late and i didn't check the gauge ground yet