Alternative Fuel Sender

[GhostZero]

Hey CTD folks-

I am thinking of putting one of these in the fuel tank of my 06:

http://www.aircraftspruce.com/catalog/inpages/westfuelqty3.php

And then installing an additional digital gauge for it in the cab. The goal is to accurately measure fuel consumption, for which I will need an accurate reading of the fuel level before and after fueling.

The idea behind this sender is that it works on capacitance, rather than a float, to determine the fuel level. There's no moving parts (to wear out) and my impression is that the readings are much more accurate (after all, this is an aircraft grade piece of kit).

I find myself dissatisfied with trying to figure out how much fuel is in the tank with the standard gauge, and what my fuel economy is. With the incredible prices of fuel I seem to have this compulsion about being able to accurately measure just how much I'm burning.

Does anyone know of a digital gauge that works off the factory computer that will save me this kind of effort?

The other option is to simply take a feed of some sort off of the factory sender (I can work out some electronics to make sure there is no signal drop to the factory gauge) and install a digital gauge of my own design/construction.

Does anyone have any thoughts about weather or not this is a horrid idea?

Thanks for your thoughts!

 

[rweis]

I am working on puting a Stewart Warner sender attached to the OEM canister. Better quality etc etc etc. Have to put in a 2700 ohm parallel resistor to match (SW 35 - 240 ohm) the OEM gauge ohms (20 - 220 ohm).



Also changing the float to a poly or brass float to avoid the deterroiation problem of the OEM float.



Parts are enroute and will take about another week to get here, then + 2 weeks to get time to drop the tank and install.



There is a thread about going to a capacitance sender you might want to lookup.



The DC fuel system expects 20 - 220 ohms. Feeds 12v to the sender, gets back a voltage (. 6V - 7. 0V) then converts that to a data bus signal through the PCM.



Should be interesting,



Bob Weis

 

[GhostZero]

Ok that is REALLY useful information Bob... Let's keep in touch. I was actually thinking of not touching the factory fuel system just in case I ever want to sell the truck, and because of warranty issues. I figure with the additional sender I'd only jack the warranty of my tank, and my dealer is actually pretty relaxed about user mods (with the exception of chips/programmers).

If I simply dump the fuel from the tank, drill a hole in the bottom, and install the wastach sender I should be able to get a real precision reading from the sender- Initially I'd only have to use a vom, but then could just install a digital gauge on the dash.

Alternatively, I could just take a splice off of the factory sender, and put in my own gauge. I might try doing that before I muck with the tank.

 

[JR2]

A buddy of mine (and fellow tdr member) mentioned that he was using a sender from centroid for his tanks. They set one up so it had the proper voltage output to match the stock sender.
All I could find online was http://shopping.rexmar.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=centroid

 

[BarryG]

JR2:

Would you please tell me who that is or ask them to PM me. I would love to do it. I have been in contact with Centroid and they have what I want and for fairly cheap. However my problem is I want to use the stock gauge and am unsure of the wiring connections needed to make it work and so are they. It interfaces with the ecm and pcm and does not go straight to the gauge. I do not want to fry either one of those and my electrical abilities are limited. There was a member tractorface who posted and said he did it a couple years ago or longer but have been unable to contact him. He doesnt accepts pms and hasnt responded to email but I also noticed he hasnt posted in quite a long time so not sure if he is still really around. In any case if you could ask your buddy how he wired it up I would very grateful

Thanks in advance

Barry

 

[rweis]

The voltage is suppose to be . 6v to 7. 0v. I would think as long as the Centroid fed that to the PCM it would not know the difference as to where it came from.



The PCM feeds 12v to the tank rheostat, the rheostat feeds back . 6v - 7. 0v, the PCM takes that and converts it to a data bus signal to fed to the gauge. I think that's how it works.



Bob Weis

 

[juicedcummins]

I did this on my 99 and it worked flawlessly. I got a sender from JC whitney that was in the right ohm range.

 

[BarryG]

While reading this please remember I am an electrical idiot.



The CTD has a two wire connection. Bob says one wire feeds 12v to the stock rheostat and the other wire sends back the signal to the pcm. If I remember from looking at the manual that seems right but would need to double check.



Now the cap sender has a 3 wire setup

The send wire on the sensor is supposed to go to the send wire on the gauge. Which I would guess is the one going to our pcm and then on to the gauge.



The POS wire on the sender is supposed to be 12v ignition switched. Which I would guess would be the positive 12v from the pcm or wherever it is coming from.



Next there is a ground terminal that obviously should go to ground.



Asssuming I can find which stock wire is which does the above sound right. I am thinking if I reverse the polarity 12v is going to cook something down the line compared to the . 6v to 7v Bob mentioned.

 

[Vaughn MacKenzie]

Hey CTD folks-

I am thinking of putting one of these in the fuel tank of my 06:

http://www.aircraftspruce.com/catalog/inpages/westfuelqty3.php

And then installing an additional digital gauge for it in the cab. The goal is to accurately measure fuel consumption, for which I will need an accurate reading of the fuel level before and after fueling.

Ghost, not to knock this thread off fuel sending units but for accurately monitoring fuel flow and consumption how about one of these fuel flow sensors http://www.floscan.com/html/blue/generators.php

Check the one further down the page - it's a combo gauge showing engine hours, fuel odometer (total lifetime fuel burned), etc.

Vaughn

 

[Vaughn MacKenzie]

Just looked some more on the site and found one for vehicle applications (one posted above is for generators) http://www.floscan.com/html/blue/offroad.php (scroll down page)

It reads 0. 3 to 30 GPH so it should cover most Dodge/Cummins applications. It uses a sensor on supply and return lines so it can compute usage. It's a spendy bugger but just imagine how cool it would be to have one. Then if someone could interface it with the Dodge electronics to get instantaneous ACCURATE MPG readings that would be the BOMB.

 

[rweis]

The second one is "off road" and I think it says it only records when the vehicle is stationary if I read it correctly.



Bob Weis



I have a fuel float from the stationary gauge I am puting in the bed aux tank. I cut it in two pieces and it seems to be a light "coke" type material. I am going to float the cut sides in diesel fuel and see what happens to the exposed material.



The orgional float had a hard pressed type skin and that might have been a mechanical "seal" to the actual float material. We'll see