6.7L MegaCab

A few days ago when I was diagnosing the issues I was having on my truck, I decided to go through the TIPM configuration menu and came across an area to change the fuel capacity (good to know if you are installing a larger tank). The number that was in there, was 129. Not sure if that was reading the current state of the tank (it was at 1/4), but rather clicking the back button, I clicked 'Done' which stores whatever setting you changed or if there is an option to exit, scroll to the exit and clicked done to get out of the menu without making changes.

Anyhow, after I refueled, the fuel gauge only read 3/4 tank. So I went home changed the number to that of a 35 gal tank but in liters (assuming those numbers are reported in liters instead of gallons) and the gauge then read full. However, I have driven a lot the last couple days and the gauge should be reading at least 3/4 by now. On my way home from work last night, the EVIC showed 800 miles DTE.

Does anyone know if the fuel capacity setting in the TIPM is in gallons, liters or another setting? Is there a proper way of setting the fuel capacity, such as if you are installing a larger tank? I need to get it back to it's proper state, just not sure what to do at this point.

I did order the service manual from Tech Authority a few days ago, so hopefully that will shed some light on it.

Thank you in advance for any help or insight into this.

BigIron70

Dealer can do a TIPM reconfigure but will charge you for it. Most likely the TIPM needs to be updated along with brake controller and PCM and CCN.

6.7L MegaCab

Thank you, Sir for the help. I was thinking I may have to do that. What would you recommend I do about my Black Maxx? That is the reason that has kept me from going to the dealer in the past? I'm already out of warranty, and about 12K shy of 100K miles so that is no longer a concern. I just don't want them to lock my BM out of the ECM. Do I return the ECM to stock when I bring it to them? Anything else I should do?

BigIron70

I would have them do a Reconfigure only if you are using a programmer. That will set every thing back to stock but do not have them program PCM. It could disable your programmer.

6.7L MegaCab

Thanks for the info. Considering the dealer closest to me is not known for their service, I'll have to wait. Can't afford the downtime if they lock out my programmer.

The good thing is, I pulled up the digital readings for the fuel capacity and fuel level sensor. It was reading 44 gallons and 1.65V. So I changed the value (in the fuel capacity settings of the scan tool) to the smallest number, which is 36, and it read 19 gallons. So I topped off the fuel (around 13 gal), still wasn't reading right. I changed the number to 100, then the digital reading displayed 36 gallons and the fuel level sensor showed 0.65V which would be about right for a full tank, except isn't the tank 34 gallons on the Mega Cabs? The fuel gauge on the IC appears to be working right and the DTE was closer to what it normally reads after filling up: ~580 miles. Next week, I'll top off again and see if I can adjust it to read 34 gallons.

After all of this, I'm still uncertain what the fuel capacity readings are in the TIPM. It is definitely not in gallons or liters, so it may be a percentage, but that doesn't make sense as the value must be between 36 and 290. Maybe the FSM will shed some light on this when it arrives Thursday.

To note, I called AutoEnginuity thinking it was a way they set up their software, but they said the scan tool and software only pulls and displays data that the TIPM or any other component is configured to display so all the values come directly from whatever system you are looking into: TIPM, ITBM, CCN, ECM, Radio, ect.

BigIron70

I have a 2011 I'm working on at my job, it was a trade in. I'll take a look at what the settings are in the TIPM, I can then print out the setting in TIPM. You can thank me later

6.7L MegaCab

Thanks BigIron! What's your favorite pastime beverage?

6.7L MegaCab

Well, I received the 2010 FSM this morning from Tech Authority. It doesn't say anything about the fuel capacity other than a Fuel Tank Size of 20.5 gallons, Fuel Level Sensor #1 @ 0.65 volts, and Fuel Level Percent of 80% all read from the PCM with the Key On/Engine Off.

For the TIPM, all it provides is Fuel Level Sense 1 @ 1.9V and Fuel Level Sense 2 @ 5V.

It doesn't mention anything about what the setting should actually be and it doesn't list everything the Scan Tool is reading from the TIPM, which is strange as it obviously provides a reading for Fuel Capacity as well. Oh well, I'll fill the tank up again and change the setting to read 34 gallons, since it was reading 36 gallons with the Fuel Capacity setting @ 100.

Thank you again for the help BigIron, but it appears that what my Scan Tool reads will probably be the same as what the wiTECH will probably display, but I am interested in what you were able to find out.

BigIron70

Sorry I didn't get back sooner but our internet went down for 2 days. Just came back up today and I was back logged with check engine lights and RRT's all day. I did check a few TIPM's and was unable to find any setting for fuel capacity in the configure report.

6.7L MegaCab

It's all good! It's kind of funny how Chrysler in their infamous wisdom has made it so productivity comes to a stand still with no internet. The fuel capacity setting is probably one of those settings Chrysler doesn't want messed and only includes the settings listed in the SM.

I filled up this morning and brought the laptop and scan tool along with and fixed it.

The fuel capacity number I had to use was 92.5 = 34 gallons. 100 = 36 gallons; 90 = 33 gallons; 95 = 35 gallons...so there definitely doesn't appear to be any logic with those numbers. I guess you would have to be an engineer to figure it out.

At least I know if I ever decide to get a larger replacement tank I can manipulate the numbers to what the tank is rated for.

Thanks again for the help!