OMG!!! How do I drive this thing! (Yes I'm the newbe)

[CoreyPerez]

Alright, here is the situation. I've just driven the truck barely over 300 miles today, and used just under 1/2 tank of fuel. The truck was driven about 65/75 mph in O/D (Automatic). Now for the questions:



How does this truck use fuel. IE: does the fuel hit "F" fast, then settle down through the rest of the fuel range on the guage? (mine hit it at aprox 60 miles (in town)



What type of fuel economy should I expect on a full tank in both O/D & D (towing) I've seen 17towing & 20unloaded. Is this correct? About how many miles will I get off this tank?



I seriously doubt, but I'm going to ask, can these trucks tow in O/D? if so, under what conditions. (Automatic)



I've heard that these diesels are more fuel efficient when ran at high RPM's. Is this true?



What speed should I expect to beable to drive in "D" for long durations (12hrs etc... ) & at what speed.



I wanted to get an "Idea" of what to expect when I would be towing this coming weekend (14' covered trailer). I ran the truck at aprox 65mph in "D". When I ran this way, the truck felt "Heavy". I don't know if it was because of the rpm's or due to the lack of the "O/D" Is this beyond the limit of the design?



Do pickup's get better fuel economy with the gate up or down. (Has anything ever been proven on this)?



Lastly, does this truck have a "Low Fuel Light"?



Well Thanks for any information. This is the first time I've driven it for any duration. As I said, I put about 300 miles on it just in a few hours. Thanks guys!



Corey

Ya, the newbe

 

[Vaughn MacKenzie]

Well Corey I was going to start off by telling you how to break that thing in until I noticed it already shows 114,000 miles.



I've found my fuel gauge drops fairly linearly most of the range except the last 1/2 goes faster than the first half. Mine has an annoying stupid Low Fuel chime/light that goes off every time I fire up once it's tripped. Would like to get rid of it.



Cruising down the highway definitely leave it in OD. Best efficiency on a 12V doesn't come from revving it up. . . I think they do best around 1700-1900rpm?? (I'm a 24-valver so I'm not sure on that!) Most guys tow in OD, unless it is a heavy load on hilly terrain (once again guessing since I have a 6-speed)



Why am I posting anyway??? LOL Well that is my worthless 2c



Vaughn

 

[swamp rat]

Howdy Corey,

Welcome to the gang. Vaughn pretty much nailed it . My '95 gets the bets fuel efficiency between 1700 slightly under 2000R's which is also where the best torque numbers are located. If you are getting 17-20mpg loaded to unloaded, I'd say you ought to expect between 550-700 miles per tankful. I'd definitely be looking for a fuel stop around 600 max. as an aside, I've found I can run almost 100 miles after the point when the gauge just touches the "E". YMMV due to variations between trucks and gauges.



As far as driving for 12+ hours, I'd wager you would probably get tired or need to go 10-100 before the Cummins needed a break, unless you're hauling a heavy load in the desert or mountains.

 

[SlyBones]

I can get 21-22 driving at 1700, about 19-20 at 2000, and it does down fast from there. I thought I read a post from Joe D. long time ago that says 1700 is the best economy. And its true for me.



Yer gonna find mileage all over watching these threads. In the end 2wd gets better than 24w, 5sp better that auto, 2500 better than 3500, flatlanders better than mountain men, 3. 54 better that 4. 10, etc.



A guy with a 3500 4x4 QC, LB, Auto, 4. 10 that lives in hilly terrain will get quite a bit less mileage than a 2500 4x2, std cab, 5sp, 3. 54 that lives where its flat.

 

[Cooker]

300 miles and 1/2 a tank of fuel sounds right. To be safe, and to not drain all the junk from the bottom of the tank I usually fuel up with no more than 550 miles on the trip meter.



Just for grins, check to see if you speedo is correct. You may be suprised. Your fuel economy could get better or worse depending on your situation.



Leave the gate up. Dodges were designed to run (and get better economy) with the gate up. Check this out for proof: http://mars.acnet.wnec.edu/~ehaffner/did.htm



There is a low fuel light. It is supposed to come on when there is seven gallons left in the tank. Don't trust it. Mine came on while driving to the fuel station and I was able to put almost 31 gallons of fuel in it.



You must have 3. 55 gears. If no the motor would be screaming pretty loud @ 65 in drive. Go ahead in tow in OD if your weight isn't too much and you don't notice the truck lugging (the truck will grunt down to some low RPMS, but the transmission won't like it). Keep the RPM's at 1500 as a bare minimum, especially towing, and like already mentioned 1700-1900 is the sweet spot for peak torque and economy.



There was a thread a while back that Cummins designed and tested these engines to run 2500 RPMS for 24 hours at a time (obvioulsy as long as vital temps are keeping cool).



Drive it like you stole it The truck is governed fairly low so you can run it pretty hard without hurting it. Just make sure she stays cool and you are over 1500 RPMS.



Just my $. 02,

Ryan

 

[MuddFlapp]

OD Auto

I would do some more research on towing in OD with a load. I burned up the Auto in my 2500 hauling a load in OD that I thought was light enough. Total bill, $1500.





Other than that, just drive it and enjoy. I run mine @ 2500 rpm (when I need to) for hours at a time. With my 4:10 gears that translates into about 75 mph. Never had a problem and never over heated.



Have fun.



Gene Earl.

 

[DieselDoghouse]

Welcome aboard Corey! Here you will find great advice from some of the most talented truck-nuts around! Your mileage sounds about typical for the setup you have. I agree you will see the optimum around 1700 - 1800. Remember unlike a gasser (spark ignition) our compression ignition engines don't "feed" based on engine speed so much as based on load their haulin' (Interesting write-up about this for gassers in current 4-wheel magazine with gas @ $2. 00/gal). In brief this is because we can run over a wide range of fuel:air ratios, gasser can do this (we're about 65:1 idle and 25:1 full load, gasser is about 15:1 or it quits!!). This is all done by the injector pump - pretty cool! One thing I found helped my mileage - a boost gauge for the turbo. If you right foot gets heavy your boost will rise as you suck more fuel. I try to keep boost below 10 psi if possible (ya, right). Speedo keeps you legal, boost keeps you cheap!! Enjoy your new ride!!

 

[CoreyPerez]

THANKS GUYS!!!



I'm still a little confused about towing in O/D. I guess I'll just have to tow in "D" to be safe. I may run up on the flat lands in O/D when I'm empty though. I'll be running through the Mountains for a bit on the way up to and back from Michigan.



-- Side note, I don't know if any of you seen my other post, but I'm running up to michigan empty and back loaded. If anybody needs anything hauled from NC to MI lemme know! --



I did notice a ?? problem ?? After driving for about 2 hrs in O/D at the speeds posted earlier, and coming into a town or slowing to about 45mph (rpm's @ 2250 aprox) the truck felt like the torque converter was "fluttering" in and out of lock up. Is this something that is normal? Oh, gear ratio is 3. 50:1 as per the underhood sticker.



Thanks again guys, You are all a great help.

 

[samb]

I do most of my towing in OD and cruise control. On interstates set about 69 and it just keeps going. On long hills if the speed drops down to 60 it will drop out of OD and the speed will start to pick up. If the hill is long I will hit the od button so that it want go back into OD untill I top the hill. That way it want be shifting to much. See in my sig my trailer weight around 11k. So tow in OD just don't let it hunt.



Sam B.

 

[jsutterby]

Corey,



Welcome to the TDR, this is a great bunch and you will learn more about your truck than you thought possible. Here are a few tips I have gleaned from the transmission "guru" Bill Kondolay, whose speaks from years of daily experience with these trannys.



1) As mentioned before, keep your RPM's high (1700+)

2) Do not engage overdrive below 50 MPH with 3. 54 gearing

3) Change transmission fluid at recommended intervals, cheap insurance!!



If I am towing, I usually use my O/D lockout button to get rpms up in 3rd, then go to overdrive on flat terrain at about 60mph+. The main thing is don't lug, keep RPMs up. Just my . 02!



Jason

 

[Steve M]

Corey,

Glad to see another Cummins owner on the site! You should have many happy miles on your truck with the Cummins. Your observation of the torque converter at 45 is probably normal. You're right at the speed that it locks or unlocks. My new one does it too as did my '95 auto. If it does it at other speeds with or without a load, it could be a throttle position sensor going bad. Not an uncommon problem with these trucks with auto trannies.

You can tow in O/D unless the transmission is hunting in and out of O/D. Then lock out O/D. You can run it at 2500rpm as long as your seat can take it. I did it for many miles when I had my 98 12v with 5spd/4. 10.

 

[Ron Bissett]

Corey things to do 1. carry extra diesel 5gal until you are sure of guage . Do not let it run out of diesel or you will be in for a world of problems . 2. change fuel filter after reading instructions 3. check air filter change if dirty. 4check and or change fluids . 5 service batt and clean tighten . 6 order shop service manual for your truck . 7 keep reading post on TDR for a world of information you can use to keep on trucking . Hope this helps , and welcome , Ron in Louisville KY

 

[mfburns]

Welcome aboard Corey!!

I have a 94, 2WD, Auto, 3. 55 rear, K&N Filter, Leer Cap, 115,000 miles, stock 2500. I tow a boat trailer, about 4000lbs, with no problems. On the Interstate I set the cruise at 70, OD on, and it runs longer than I can sit, RPM at 70 is about 1750-1800. I get about 16-17 MPG towing the boat 400 miles from Philladelphia to Lake Placid area.

If I hit hilly country on back roads I turn off the OD after it reminds me by kicking in and out a few times. I can't advise on HEAVY loads but I think the truck will tell you what to do. If it keeps shifting turn off the OD.



I get 19-21 empty depending on the speed, traffic, fuel, etc, mostly 19. 5-20 MPG, lower in the winter. If I keep the engine around 1700 RPM, (67 MPH), I get the higher milage. Last tank was the best in a while because I kept my foot out of it. My fuel gauge hasn't worked for about two years so I can't help you there, my low fuel light is on all the time but I look for a stop after about 550-600 miles and check my milage each tankful.



Buy a manual, it helps explain a lot of things. Change the oil and filter, buy good fuel and run it.



Good Luck