BarryG

Well I finally got around to installing a capacitance type fuel sender to replace the stock unit. I have replaced it twice already and was unwilling to spend the money on it again.

What you need is a sender. I got mine from Centroid
http://www.centroidproducts.com/ . You need a 220/20 ohm unit, which is not listed but they will do it no charge. They have different mounting styles. I used the standard 5 hole SAE mount (no charge) but they have other options. You also need to know how long it needs to be and they will cut it and calibrate it for you. However you can cut it yourself if need be. I ordered mine 14.5 inches long. They say it needs to be 1/2 inch off the bottom mine ended up being about an 1 inch off the bottom. Had I been able to measure it accurately I would have gotten it 15 inches long. It will depend on where you place it as to the length you will need

You will also need a drill, 1 inch spade type bit or hole saw, 3 butt splice connectors 16-18g size, 3 ring connectors/ends. I also used a 3 wire GM Weather Pak Connector 1 ea male and female. Also need some type of gasket sealant good for diesel fuel. I used Permatex Form a Gasket #2, so far it is working fine. You will also need 5 bolts and nuts. I used 10/24 1.5 inches long with a washer on top, washer underneath with a lock washer and the nut. (1/4 inch will not fit nor will 6 mm)

Remove the tank from the truck. You might be able to do this by removing the bed but you may find your wires might be a bit short to work with.

Drain remaining fuel if not already empty.

Clean top of the tank to help keep any crud from getting into the tank once opened up.

Remove cannister lock ring. A few soft hits with a hammer and chisel got mine right off.

Remove the module. I checked mine and was suprised it was very clean very little stuff inside the screen was free of dirt as well. In fact the entire tank had little crud if any in it.

Remove float assembly from module (you could leave it in but why take the chance of the float disintegrating over time like has been mentioned on this forum many times in the past).

Set cannister aside in a safe clean place for now.

Drill your 1 inch hole in your fuel tank (it drills easily). I placed a couple shop rags inside the tank underneath the area I was going to drill to catch the drill shavings. My hole was placed on the step up about 12-14 inches forward of the module. From the manual this appears to be a spot for a rollover valve on the gas vehicles. There was a nice flat recessed area even had a centerline cross on it. The circular area was the exact same size as the sae mount for the new sender. (by the way my tank is from a 4x4 long bed qc truck either 35 or 36 gallons in size). It appears that not all trucks have the same type of tank so be aware of that.

Place new sender in your new hole and drill the 5 holes for the mounting bolts.

The sender came with a gasket and I used it but I also used some gasket sealant so if using it now is the time to apply it.

Put it all together and tighten down the bolts firm but not too much. You dont want to mess up the gasket or crack the sender head.

I reinstalled the module at this time but you could do it later especially if you are combining this with a draw straw install.

From the electrical plug that plugs into the module snip of the end connector (you might want to leave enough wire so that if you wanted to put it back you could).

From one side of your 3 wire GM weather pak connector (mine came with pigtails on them) attach 3 ring connectors/ends.

From the remaining side of the GM weatherpak connector attach two wires from the bundle you previously clipped. On my truck (2001) the two wires you need are black/light blue is sensor ground and dark blue/white is fuel level sensor signal. The remaining two wires(green & black) in that harness are unused by the vehicle they are for a gas truck. Use the butt splices(I also used shrink tubing) to connect the harness to the gm connector wires. The gm connector is labeled A,B,C (on each side) take note of which wire goes to which letter as you will need to know that later.

Now you need to run a 12v ign switched power wire to the remaining wire of the GM connector. Again take note of which one a,b or c it is.

Take the gm connector side with the ring terminals and attach it to the new sender per the directions. This is where knowing the a,b,c comes in handy.

Now put the tank back in place. Once in place just push the GM connector together.

Turn on the key in your truck and check your fuel level. Well at least after you put some fuel back in it. Mine read as follows being approx 1 inch off the bottom of the tank. 9 gals 5/16 of tank, 14 gals 7/16, 19 gals 9/16, 24 gals 11/16, 29 gals 13/16, 34 gals 16/16(full), 36 gals 17/16 (just over full). I only waited a bit after each 5 gals I pumped in then checked the level except for the inital 9 gals poured that all in at home.

Not sure if the low fuel light will work or not. Have no reason to think it wont but it was not on after I poured in the 9 gallons of fuel initially.

Anyway I hope this helps someone I wanted to do a cap type sender but was afraid of the wiring and as it turns out it is nothing at all. 3 wires two of which are already there and a simple 12 v feed. No problem what so ever.

I have some pictures but cant figure out how to put them in. If someone can help with that it would be great. I could email them to you and you could post them up.
__________________

BarryG

Here are a few pictures

BarryG

And a couple more

torquefan

Nice writeup. I hadn't heard of that upgrade. Hope it works well for you.

BarryG

Well I filled up this morning just as the needle hit "E". When I filled up after the inital install I put in 36 gallons. I put in 31.4 gallons this morning and think I filled it the same as the inital fill. So just as the needle hit "E" I had 4-5 gallons left in the tank.

By the way the low fuel light came on right at 1/8 tank.

'pants

I've been trying to communicate with these manufacturers and it's like they don't want to sell anything. In Centroid's case, it's like they stopped paying attention to shop-by-mail trends when the fax machine was invented.

Centroid: four phone calls only got me their lame 'no messages taken' answering machine, helpfully inviting me to call back another time. Emails and faxes to them went unanswered - I even went to the trouble to understand and fill out their user-hostile fax (!?) order form. Why are they so...1983?

ISSPRO: toll-free number apparently only works from lower 48?? And no toll number listed? I tried going through one of their dealers, and the needed answers were just not there - in fact, it seemed to be suggested through the dealer that they'd be happy to sell me a sender... that they helpfully indicated was of the incorrect resistance-range, and without offering whatever the correct one might be.

I might have to go with a sight-glass at this rate.

cguyfish

Just wondering if anyone else has try'ed this.. Can'nt tell where he mounted it on the tank

'pants

I mounted it at the high-point, a plateau that's obvious when you've got the luxury of seeing the tank from above. No sense in making the sender's gasket work to hold back any more fuel than necessary, and you'd want to gauge from there anyway, since that's the point that allows you to check the full range (from empty to over-full). It's an air-pocket that won't fill until the truck is moved, so it's not likely to see much fuel under pressure at the gasket.

My sender is still installed, not wired, useless, filling the hole I made for it. I'd not likely go through that costly exercise in futility again, unless the manufacturer provided a guaranteed-fit package that was pre-engineered to work with the level gauge...(never, that is.) Consider also that I've got a dump kit installed, so access to the top of the tank is super-easy - if it hadn't been for that, I'd probably not have even tried this approach - I can't imagine how many times I'd have had to lift the bed or drop the tank to get to anything...

-Dave

cguyfish

Thanks I've got my bed up now. Pulled my module out. Was wondering what was best rought to take. Most probally gonna get one of them straw outfits from Raptor or Fass

cguyfish

Guess I'll replace with stock sender....?

BarryG

Well my install is still working good so far. Since I have driven it for several years now I would stick with the 14.5 inch sender assuming it was installed in the same place and it is the same tank. I did not mess with calibrating mine at all it worked out just fine. One thing of note is that the calibration adjustment will only lower the full level it will not raise it above the high point which is how it was sent to me

Stock sender replacement would certainly be easier as long as your truck doesn't eat them like mine did I was only getting about 40-50k out of them however not everyone has it that bad not sure why mine crapped out so frequently but nonetheless less it did so I opted for a different route as outlined earlier in this thread

Steven Turner

Hey Barry G. Was looking at your pics and was confused to why you wired back into the old module instead of from the wires from the truck. Dont understand how you are getting power and getting the fuel gauge to work

BarryG

Wow this has been awhile
in any case I did not go back to the oem sender. That pic while it shows the plug on the old sender it is just laying there. The other side/half of the plug is just not in the picture. I cut off the original oem electrical plug and wired in those GM weather pack plugs. The oem harness has multiple wires in it but the diesel only uses two of them can’t remember which two but I may have noted it in this thread. The new sender needs three wires the two from the oem sender and an additional 12v ignition on only power wire that’s is why I used a 3 terminal GM weather pack plug

fyi I added length to the wires and length to the fuel lines which I replaced from the oem sender unit to filter head. I had done that previously so as to make dropping the tank easy (I had dropped it multiple times previous to this install). That way I could drop the tank and disconnect the fuel lines and wire harness on the floor instead of trying to fight them with the tank in place