I have a 95 dodge ram 12v with auto, it has 4.11 gears, with 285 tires.
100 fuel plate,
Plate pushed forward all the way
Star wheel turned all the way
Straight pipe
Homemade intake w/ K&N filter
Boost elbow, have the wastegate closed off 100%
176k on the clock

Thats pretty much it and its stock, i change the fuel filter w/ every oil change, have cleaned the pre filter or grid heater filter which ever its called.

Anyways with all that said, im only getting 13-14 mpg in this truck and its killing me. I can get a little over 400 out of each tank and have to fill up again. And at 75-80 a fillup its becoming very expensive with all the driving I do. I always hear of guys getting 18-20mpg with these trucks and I would love to see these numbers. My driving is about 50/50 cty/hwy and sometimes 40/60 (cty, hwy). This truck in stock form is a SLUG. At 65mph im about 1950rpms, and its nice to atleat go 70 on the interstate to not cause accidents since everyone else is going 80.The best I ever got was maybe 16mpg with the truck taking it VERY easy. Im going to move the plate back and turn the star wheel back and see what it does. I want to check and possibly advance my timing and want to replace the overflow. Im also going to check the FP, is this avg. for the described truck? Are the gears killing me that bad?


Thanks,


Garrett

 

This time of the year the winter fuel will hurt your mileage.
Id look into rebuilding that transmission with at the least a valve body and a good TC. The OEMs are the most inefficient things ever. I think that was done on purpose to save the weak trans behind em.
You should also check your fuel pressure. About 25 at idle and 35 at 2000rpm no load is about right. The overflow valves will wear eventually and let the pressure dip.
Make sure youre running good boost also. a boost leak could lower your economy.

 

Alright, i went outside and figured id tune it down by sliding plate to stock all the way back and turning the valve on so my wastegate isn't pinched. And of course the truck returned to the slow as snail form it was when stock. This was still with star wheel turned all the way and 100 plate, intake, straight pipe. So i then closed off the wastegate alowing maximum boost, still slow as a slug. Honestly here the best way to describe it, taking off from a dead start you can push the pedal 1/4 all the way up to full throttle reguardless it still only accelerates the same speed. As if it has one gear, most vehicles pedals to the floor = faster take off, not this truck its the same the pedal just gets pushed further to the floor. I swear to god its the scariest thing trying to pass a car it feels like your putting a 5spd in 5th gear trying to take off it doesnt go the LEAST BIT FASTER it just slowly starts going, and of course your screwed if someone is coming in the opposite lane because there is no pickup whatsoever so pass the car in front of you. I guess i have no choice but to slide the plate forward again. I will have **** poor milage but atleast its decent to drive and has some *****. Im going to check the FP, also on the boost subject, those plastic boostlines that run all over under the hood. At the end of each plastic hardline where it plugs into a rubber booty, the end is like flared so that it seals good. Thing is these things are either old or just more fragile than glass, well I have broke the one running into the afc housing, and tonight another than runs on the drivers side. I just replace them with the same diameter vacume line but the ends of the replacement aren't flared. On my 4wd underneath i just put superglue to seal it inside the rubber. Does this matter? Whats the best way to check for boost leaks?

Also i honestly dont have the money for a transmission or upgrades to the tranny right now. My grandfathers 96 ex-cab long box 2wd auto will get up and go quick and it has ***** all the way around compared to this truck. It feels like im pulling a fully loaded trailer.

garrett

 

those big tires certainly dont help any

 

really cant coment on the auto but with 4.11 where are you're cruisin RPM

 

Ha, 285s are little, i had 40s on this truck and could pull 13mpg. I think my gas milage gas gotten worse, i do want to mention when i went to remove the afc cover 3 of the bolts were probly finger tight and it was a little wet around the cover. I try to stay at 65 on the hwy, and around town local main roads 55-65. I sometimes hit 70 on the highway. Like i said at around 65mph im taching 1900-1950 rpms.

 

Most of the high MPG trucks here are 2wd and near-stock. Low ratio differential on a 4wd is a proven fuel hog. Your best chance to improve milage is to return the truck to stock and then make one mod at a time. If it doesn't help, take it out. Also don't make smoke, it is wasted fuel. Tred lightly on the go-pedal.

 

How much of a difference do 4.11s make over 3.55s? I would think the truck would get up and go quicker with the 4.11s too. My old z71 would move alot quicker than a friends w/ same truck but w/ 3.55s. I had the truck lifted for like 3 months then lowered it down but i had 40s on it and could pull the same fuel milage im getting now. I think something has gotten worse since I've bought the truck. If i advance my timing will it help?

 

This won't really help with your question, but you are correcting for different size tires, right? If not, you're getting better mileage than you are calculating. I think you're about 8% off using 245's as stock vs. 285's now.

 

we have 2 identical trucks (well they were when they were new) except ones a 3.55 and ones a 4.10. the 4.10 was alot slower then the 3.55. First move your star wheel back. you can leave the plate forword but I've found just moving the starwheel back to center I could get 19mpg but with it full forword I got 12. The plate location didnt matter nearly as much. Also you could use larger tires. 35-37" if there a light weight tire. The BFG AT KO in 37" is very light for its size while in 33" its heavy. Tall, narrow, and light for tires. 33" on a 3.55 gear gets about 21mpg with ULSD. with 35's on a 4.10 I get about 17 now with the ULSD. hope this helps.

 

When I got my 95 it was bone stock. Seems like the truck in stock trim is low enough on power to hardly be able to get out of its own way. That stock 160hp pump needs a governor spring kit and some delivery valves to be able to move like it should.
the cam plate will give you some power if you slide it forward, but you really need to get a better cam plate. Then comes the need for a transmission..
Id say get gauges and that trans done real soon

 

Well I can say my power loss last night is due to a mistake I made. Last night i was thinking and i had remembered I unbolted the brass fitting which connects the boost line from the afc housing the the intake. Well i never re-connected it, so today i reconnectded it and wa-lah, instant power. I slid the 100 plate back all the way too.

To adjust the star wheel don't you have to unbolt the allen bolt while the cover is off the afc housing? Lance helped me the first time since I had never done it before and i couldn't remember. Also I do plan to run 35s to help lower rpms, i will probly run bfg a/ts on h2 hummer rims. I want to do the 4gsk and get the heavier springs from tstproducts. I notice alot of guys just run the 3gsk, is there a reason why?

 

This is a strange question on a fuel economy thread.

 

The governor wont allow you to make use of the higher revs.. you can use a 3k spring set on a stock motor ok, but if you go with the 4k rpm set youll need 60lb springs because of valve float possibility.

 

I've decided that the reason for my (and probably your) bad fuel economy is due to a combination of things. Having almost 200k on the truck calls for a lot of maintenance. All the moving parts around the truck get old and build more friction.

I'd say check the fuel pressure; from there you can check the overflow valve, lift pump, fuel filter, etc.

Make sure everything from idle speed to the shutoff solenoid to the throttle cable is in proper spec.

Change the axle, transmission, and transfer case fluids to a good synthetic (expensive I know...).

Check the wheel bearings and check the brakes to make sure they're not grabbing.

Check for boost leaks, fuel leaks.

Make sure your tires are properly inflated and get smaller tires (235/85/16).

Keep your truck light, get rid of the unneccessary junk.

UPGRADE TRANNY. I feel like the stock torque converter kills my mpg. It's so inefficient.

Drive slow... 4.10's aren't going to help but you'll have to sacrifice going slow (under 60 mph) for fuel economy. Wind resistance plays a big role.

This list above is just to name a few. Basically, try your best to get your truck back to the working condition of when it was new. Of course all this takes time, which I don't have...