Fuel Tank Size Calibration (Good and Bad News)
 

The good news is the latest IDS, version 71 is out - in fact it has already had two updates and the latest version is 71.02. As promised by Ford, the new version includes a programming parameter to change the size of the on-board fuel tank.

Now the bad news - the largest parameter is 40 gallons. Not sure why they limited it to 40 when most guys upgrading their tank size are putting in 50 gallon tanks. Perhaps Paul Bruckne can raise this issue and see if they are going to change this. It would be better if they would allow entry of variable sizes rather than fixed sizes as it is now in the IDS software. Here is a screen shot of the calibration screen and available sizes:

http://i57.photobucket.com/albums/g2...elTankSize.jpg

:-X15

That's a bummer. It looks like Ford is allowing only tank sizes that come OEM. This is disappointing. Thanks anyway Dennis.

IDS does allow you to select 2 tanks and any combination of volumes shown above - so you can select, for example, 2 tanks with 26 and 26 for a total of 52 gallons - not sure if this will actually program that way nor do I know if IDS will require 2 sending units (which is also programmable) if you tell it you have 2 tanks.

(I presume the dual tank config is for chassis cabs?)

Not knowing the DTE and fuel level calculation algorithms, I suspect they use these amounts for the initial estimates so theoretically if the BCM accepts this programming it will get the guys with 50 gallon tanks a lot closer than they have now.

I'll try programming my truck with these settings to see if it accepts them and report back.

I remember a post before Xmas that you had contacted the engineer responsible for the algorithm used to calculate the amount of fuel used - which seems to be inaccurate in some trucks (particularly canadian ones). Did you ever get a reply??

thanks

26 plus 26 = 52. My Titan tank holds 51 gallons. If this works, i am happy. If Paul can see if the capacity can be 100 gallons, even better.

Since ordinary people, like me, don't have access to one of the Ford programmers, is there a PDF showing all of the screens and values?

I'm just curious what things are adjustable in my truck.

Were you able to get the PCM to take the programming? A 52 gallon tank size (1 sender with 2 tanks at 26 gallons each) would be okay with me.

Sounds like this set up is more useful for people purchasing cab chassis that come with several tank configurations and are often altered at the upfitters.

Yeah. sort of. But even there these static tank sizes don't make sense. The customizers could build anything they need and shouldn't be restricted to these few options.

I am hoping to hear some good news from Paul Brukkne.

Okay here is where I am at:

I went and filled my tank this morning so I know what my starting volume is. I then programmed the PCM with dual volumes, both at 37 gallons. Checked for any DTC's, etc. and no problems so far.

I then changed the # of fuel tanks to 2 and immediately my fuel gauge went to zero and I got the low fuel warning. So I changed the # of fuel sending units to 2 along with the the # of tanks at 2 and same result. No surprises there.

I then thought I will replicate the issue of guys with 50 gallon tanks by putting one tank at 26 and the other to its original amount... Except, I can't since resetting to ?? is not an option. So I have both at 26 at the moment to see if it correctly calulates my fuel.

If it calculates correctly then we will know this will work for sure for the 50 gallon guys. But I have a feeling it will ignore the second 26 since there is only 1 fuel tank and 1 fuel sending unit parameter and there is no way for me to get the second fuel tank size to reset to either 0 or "??" which is what it was originally. I suspect it will calculate fuel thinking I have a 26 gallon tank instead of the 37 gallon I do have.

Anyway, hope my suspicions are proven wrong.

Later.

rd - I'm not sure I followed. I'm planning to try this combination:

2 tanks @ 26 gallons each with 1 sender. Will that work?

Epic

I doubt the computer would allow 2 tanks with 1 sender the logic just wouldn't flow

Nope, that was my first attempted "workaround". Two tanks, one sender = low fuel warnings, fuel gauge to empty and a couple of DTC's.

So with 37, 37, one tank, one sender as the settings - no warnings and no DTC's - it works, but I can't tell if it is calculating correctly or just ignoring one of the 37 settings since the other parameters are one tank and one sender. So the real test is 26, 26, one tank, one sender. If that works, we have a solution.



Convoluted huh?