(MPG) 2015 laramie longhorn limited 3.55

[jacobsën]

I just purchased a 2015 Ram 1500 Laramie Longhorn Limited with 3.55 rear end. It's got 175K and its mint inside and out. Motor is clean as well. So far it feels excellent. Being a bit of a convoluted package I figured I better join a forum, by the way I'm in Minnesota.
I have had it for about a week now and I have noticed my MPGs are between 14 and 16 even though I've been trying to hyper mile at 55 and 65 mph to test the efficiency. Also I had a pickle the first time I drove it more than a few miles where there appeared to be an ice dam in the filler neck preventing Diesel from being able to go into the tank from the filler nozzle. I theorize that the the return style fuel system was Heating the fuel in the tank. Causing the air inside the tank to condense. Subsequently steam was transiting up the filler neck, freezing near the opening making an ice dam.

I poured a bottle of heat into the filler neck and I watched steam rise out of the hole and the slight sound of sizzling. I assume that was the heat melting the ice. Then I put about 20 gallons in. Before this process there was one quarter tank and the truck was stalling, I had to restart it with an extended crank for a few blocks to get it to the filling station. So far that seems to have fixed it, when the truck either sucked up the bad fuel or an air bubble or whatever cause the motor to stall. The message service electronic throttle-control appeared on the dash at the time of stalling. However I think that is just related to the motor stopping unexpectedly.

The temperature around here has been as cold as -20 the last couple days and it is of course winter in Minnesota. Is it a vitriolic horror to run out of diesel in this motor as it was in that era gone by? Does anybody have an insight or opinion to share about my poor MPG? I realize winter fuel isn't as good as summer fuel but the truck is rated at 27 Highway. I am also aware there has been emissions recalls and being that I purchased from a dealer I assume those recalls have been performed but I will check. My dad owns a 2014 A6 3.0 TDI and apparently my truck and his car have the exact same ZF 8HP70 transmission. With the possibility being that mine might be the second of three revisions, not sure I'll have to check the serial number or manufacture date to find out. I did buy an extended aul warranty at the time of purchase which can be prorate refunded or transferred to a new owner.

I have ordered some hot shot Secret Diesel Extreme and winter anti gel on Amazon. Curious about their stiction Eliminator oil additive. Has anyone tried that? Opinions on these things?

Also I am in search of a scan tool that can perform simple functions like ABS pump activation on both the truck and a6 tdi to do our brakes at home. There are a lot of products out there and I would like to get one device that would work on both of our cars, without spending a whole bunch of money. Any reccomendation what to get?

Thanks.

 

[Ecopete]

Welcome!
Let me guess, you found too good a deal to pass up, as the dealer had it sitting on the lot for awhile now that most look the other way when they see "ecodiesel"?
That's what I did last Feb and it had the lower fuel door froze shut as well and lots of snow and ice inside the "sealed" door from sitting around outside. Hasn't happened again but I park inside mostly.
You need a winter front on it and use the block heater to get more mpg but it's still not like summer.
Oh and good luck to you!

 

[GearHead]

I just purchased a 2015 Ram 1500 Laramie Longhorn Limited with 3.55 rear end. It's got 175K and its mint inside and out. Motor is clean as well. So far it feels excellent. Being a bit of a convoluted package I figured I better join a forum, by the way I'm in Minnesota.
I have had it for about a week now and I have noticed my MPGs are between 14 and 16 even though I've been trying to hyper mile at 55 and 65 mph to test the efficiency. Also I had a pickle the first time I drove it more than a few miles where there appeared to be an ice dam in the filler neck preventing Diesel from being able to go into the tank from the filler nozzle. I theorize that the the return style fuel system was Heating the fuel in the tank. Causing the air inside the tank to condense. Subsequently steam was transiting up the filler neck, freezing near the opening making an ice dam.

I poured a bottle of heat into the filler neck and I watched steam rise out of the hole and the slight sound of sizzling. I assume that was the heat melting the ice. Then I put about 20 gallons in. Before this process there was one quarter tank and the truck was stalling, I had to restart it with an extended crank for a few blocks to get it to the filling station. So far that seems to have fixed it, when the truck either sucked up the bad fuel or an air bubble or whatever cause the motor to stall. The message service electronic throttle-control appeared on the dash at the time of stalling. However I think that is just related to the motor stopping unexpectedly.

The temperature around here has been as cold as -20 the last couple days and it is of course winter in Minnesota. Is it a vitriolic horror to run out of diesel in this motor as it was in that era gone by? Does anybody have an insight or opinion to share about my poor MPG? I realize winter fuel isn't as good as summer fuel but the truck is rated at 27 Highway. I am also aware there has been emissions recalls and being that I purchased from a dealer I assume those recalls have been performed but I will check. My dad owns a 2014 A6 3.0 TDI and apparently my truck and his car have the exact same ZF 8HP70 transmission. With the possibility being that mine might be the second of three revisions, not sure I'll have to check the serial number or manufacture date to find out. I did buy an extended aul warranty at the time of purchase which can be prorate refunded or transferred to a new owner.

I have ordered some hot shot Secret Diesel Extreme and winter anti gel on Amazon. Curious about their stiction Eliminator oil additive. Has anyone tried that? Opinions on these things?

Also I am in search of a scan tool that can perform simple functions like ABS pump activation on both the truck and a6 tdi to do our brakes at home. There are a lot of products out there and I would like to get one device that would work on both of our cars, without spending a whole bunch of money. Any reccomendation what to get?

Thanks.

Welcome to the group.
Wow to start, even with a "tune" my wife and I both see about 2 to 3 MPG loss in the winter with winter blend. We use the OptiLube products as they have the highest lubrication factor on the market. Since you have experienced icing at the fuel neck I would at a minimum drain the water from the fuel filter and plan on changing the fuel filter at the next oil change at a minimum. Research all additives and buy what you are comfortable with.
Like you said there are a lot of obd scanners out there, again I would research what is available. There are several good ones less expensive than commercially available mechanic level tool. Some of the units sold at auto parts stores are good and have multiple levels of capabilities, like Autel. I keep hearing about a software that will do all FCA products for an inexpensive price, download to your laptop but you need communications capable obd 2 interface, Alfaobd.
Running out of fuel is not as bad as in the day, lift pump in the tank primes the system, but constantly running below half a tank does heat the pump and in my opinion shortens the life of the lift pump. Same thing I have been saying for years about gasoline pumps.
Block heater especially in your climate. FCA has been pushing the winter front, I have no experience with that as it is not cold enough in Oklahoma. Back in the day we used winter fronts even here on over the road trucks and they worked great then. Different technology.

 

[jacobsën]

So far so good with the truck. Hauled 1600 pounds of pavers home to test out the tow hall mode and no issues taking it easy and slow. Mileage continues to be dipping to 16mpg and peaking at 22. I have recently installed a bafx wifi single into the obd2 port to review what's available to see in the torque app. Egtb1s1, s2, s3 are reporting what look like accurate temperatures. However egtb1s4 is permanently stuck at -40f. Is this sensor bad or is there something else a foul?

 

[GearHead]

So far so good with the truck. Hauled 1600 pounds of pavers home to test out the tow hall mode and no issues taking it easy and slow. Mileage continues to be dipping to 16mpg and peaking at 22. I have recently installed a bafx wifi single into the obd2 port to review what's available to see in the torque app. Egtb1s1, s2, s3 are reporting what look like accurate temperatures. However egtb1s4 is permanently stuck at -40f. Is this sensor bad or is there something else a foul?

I would bet on that sensor is bad as at no time should the EGT be that low. There are four EGT sensors at different positions in the exhaust system. I would bet that you are still running winter blend diesel, as well as the intake manifold may be full of sludge from the EGR at this point and may well be affecting fuel mileage. My best mileage is between 65 to 70 mph, above 70 it starts to level out. Also the longer the run the better the fuel mileage, every time you start up you loose a mpg or more depending on the warm up.

It has been awhile since your first post a couple of questions, have you changed your fuel filter? The "Service Electronic Throttle System" is a common glitch that can be set by a multitude of situations and sensors, this condition sets the "Limp Home Mode" which stops the Exhaust Regeneration Cycle which causes a clogged Diesel Particulate Filter, catch the down hill slide there. Have you had any re-occurrence of the error message? Have you had the first AEM installed? And now the fix for the AEM hesitation and stall condition? Have you caught up with the EGR cooler recall for the 2014 to 2016 model engines?

I have really enjoyed my 14 Laramie Longhorn Limited, the transmission is flawless, not withstanding the hyper active shifting cycle of the AEM shift parameters, my air ride has been flawless, cab space is great and the number of cubby holes and storage is amazing. I really like the flat platform when the rear seats are up. I have turned off the automatic wipers and do not use the auto headlight setting, also the entry/exit of the drivers seat, too much stuff. Just a great vehicle all the way around.

 

[jacobsën]

Apparently there is a new 8 speed shifter software update, occupant restraint update and 3 l motor software update. I believe this has had the initial or original AEM fix. But apparently there is a new software update for the three liter motor according to the dealer. Has anyone else heard of this being released within the last few months?

 

[jacobsën]

Update: I called the dealer to inquire if the three studs that hold the flex pipe to the DPF are covered under warranty. The service lady said it would cost $75 diagnostic fee before tax before she could answer that question. However on the forums it seems like many people get that taken care of under warranty. I think the last entry I read on here we are someone got it done by the dealer for free was from 2019. Also she informed me just now that there is a recall for crankshaft position sensor software update. I'm scheduled December 6th for that. I wonder if I should tackle these pressed in studs myself, with a C clamp press I could probably get them out but the top one is a bit tight. Anyone else have input on that?

 

[Augiedoggy]

So far so good with the truck. Hauled 1600 pounds of pavers home to test out the tow hall mode and no issues taking it easy and slow. Mileage continues to be dipping to 16mpg and peaking at 22. I have recently installed a bafx wifi single into the obd2 port to review what's available to see in the torque app. Egtb1s1, s2, s3 are reporting what look like accurate temperatures. However egtb1s4 is permanently stuck at -40f. Is this sensor bad or is there something else a foul?

That mileage is pretty bad by comparision my lifter 2015 crew cab eco 4x4 with 34' AT tires and 3.92 gears gets 17 in the city and 23 on the highway... before the lift it was lowerer 2/4" and had 31" tires and got a whopping 24mpg mixed mileage 22 just stop and go city and 34mpg on the highway.

My guess is something is up, what size and type tires does it have? is it doing a regen? perhaps the intake is plugged? winter diesel generally dropps mpg 2-3 . maybe try some hot shots cleaner cetane booster?

Disclaimer, my tune has a tune on it which replaced the AEM tune which was forced by epa to meet promised emissions goals but killed torque and made the truck sluggish according to multiple threads on multiple forums ive read. Ive aslo been told there is a newer twaeker tune which helps that was released recently.. maybe thats what they are talking about.

 

[jacobsën]

So because I didn't like the attitude from the service lady on the phone I called another dealer who gave me the number for Customer Care. Customer care says they almost never have any good information to share but in this particular case luckily they had access to a file that was a long list of things covered under what is known as the x 78 diesel warranty. I have 195.5k miles and they informed me that I still have 35 months or 39000 miles of warranty remaining. And everything from the dpf, EGR, def system, catalytics, fuel system, sensors, intake, ecm, TCM, cylinder heads, turbo systems, throttle, any diagnostic and any repair are free of charge under this warranty. Specifically the dpf is listed as d p f and assembly so that spells it out that it should be covered. As the DPf studs are built into the DPF and there are no separate part numbers for those bolts. My next question is will they replace on warranty the intake manifold which is completely plugged with heavy greasy Coke from exhaust regurgitation. I believe that is what's causing my poor MPG. Currently my MPGs are between 19 MPG in winter and as high as 32 MPG on a very long distance Highway run to Florida from Minnesota. Otherwise City I would say I'm 21 summer and the highest I've seen for Highway in town is 27 very briefly. If I had to summarize I would say between 21 and 24 MPG average and this is with the diesel lawsuit tune.