Mileage update: Week rolled by so I gassed up and checked mileage and I am
at 13 mpg. I am open for good suggestions??
On another note I replaced rusted old front shocks today but much to my surprise the truck does not ride much differently with new shocks.

 

Are the brakes dragging?

I did have a Buick that had 120K on it that was getting lousy fuel mileage and a mechanic fried suggested changing out the O2 sensors. I wasn't getting any faults and he got me a set for about 1/2 of what the dealer charged. It went from 18 to 25 after the change.

That is a wild assed guess and is about all I can think of.

 

I checked front brakes while the wheels were off for the shocks and the brakes are free. Repacked front bearings as well. The grease cups or whatever they are had never been off!
I need to check the rear brakes next, probably next weekend.
Our ranger replaced a buick w 120K on the 3100!

 

Pressure in those huge tyres?

 

I have 30psi front and I am embrassed to say I don't remember what I put in rear. Was supposed to be 35psi. Tire width from 235 to 255 does not seem to be that much bigger?

 

It's not too much more, no, you're running just over 3 inches (total) of extra tyre, it's going to have an affect, more so with such an under powered engine.

However, it's still fairly likely it's something else - will note that whilst the stock pressures are 30F and 35R, that's for 235 tyres, not 255, which will possibly need more.

Are you running with the AC on all the time? (basically any vent setting that isn't face only or feet only, everything else turns on AC)

 

Yes our kid drives the truck to school so in this muggy Midwestern weather ac has been on all the time. I am sure short drive distances have an effect on the mileage but still
13mpg is pretty sad.

 

It's not a happy number for sure - erm, short distances etc? lots of idling at school? lots of lead footing?

Yup, all those make for terrible fuel economy, this engine is a very old design, it handles that kind of stuff worse than anything modern, the AC compressor might be on the way out, causing extra drag. But until you get a good run on it, you can't really tell what MPG you're getting - you're basically getting the "City" MPG right now.

 

I bought it out town almost 3 hrs away. Drove it home with one stop which was probably not the best idea for unknown vehicle but hey I made it! Got 17.5 mpg at sustained 70 mpg with rpms at 2500. Since it has been all city then.
Probably not much lead footing hahah as our kid is not cars however the ranger is much preferred compared to the old buick!
I am thinking about switching vehicles and driving the ranger for a week to see if that makes a difference.

 

I would do the switch test, 70 will take the MPG down a little, so getting 17.5 sounds about right.

If it's only ever done city since then, you're probably getting the best you will from that - short journeys with AC on, lots and lots of start/stop and red light idling, yeah, heavy large tyres, it's all mass to start moving again.
My 350 does well if you don't have to keep starting from a standstill, i'll get 27/28 highway, but city can be pretty low.

 

Mileage update for the week is 13.5 mpg so I thought I would double check wheel drag as someone suggested earlier. I had done it earlier but maybe on one side only, this time found I could barely turn driver side rear wheel while in neutral. Also driver side drum was lot warmer than passenger side.


Found driver rear axle seal had seeped over time and made a mess inside brake drum. Tough to tell if it is the wheel cylinder or the axle seal. I am guessing axle seal sine the biggest mess was down low with wheel cylinder being on top.


In cleaning things up found some end play in the axle but also some up and down play which concerns me more than end play.


Being late Sunday afternoon I put it back together and test drove and I will start figuring out what all is due for replacement.


Upside here is I may found one possible cause for my bad mileage.

 

Absolutely, that'll cause bad MPG more than you'd think!

Maybe a bad bearing as well? Looks like you've got some things to get be getting on with at least.

 

After freeing up the rear brake last Sunday I was hopeful to gain a few mpg's, turns out I got a whopping 14.6 mpg this last week. I am starting to think that is as good as it going to get with short trips and still having AC on and the slightly larger tires.


My friend drives a newish Dodge Ram with the 5.7 and he gets about the same mileage.

 

So are all wheels turning pretty freely now?
Running some super thick oil, or high mileage oil?

 

yeap all the wheels are free now, just double checked front also. Need to get the axle seals replaced sooner as the leak has gotten worse after cleaning all the gunk out.
I need to go over to drivetrain side to find out how to determine which wheel bearings I have, rock auto list couple of different sizes. New brake shoes as well, they are 10"x2.5".

 

Just filled up the truck and got 14.1 mpg. Replaced rear axle bearing and seals yesterday, waiting to replace brake shoes to make sure new seal is tight.


Truck needs a muffler next, I am going to go with stock replacement, who makes a good fitting muffler for these?
Any thoughts about lack of back pressure caused by bad muffler affecting gas mileage?

 

"Back pressure" per sé, isn't a thing in this regard - how many cats/mufflers on yours right now?

If you're going to get any change in the way the system runs, it'll be from clogged cats.

 

I am seeing only one cat but there is probably another one right behind the engine.

 

Just re-checked your spec again - stock for yours should be 3 pre-cats and two main cats.

Two pre-cats on the left bank i think, with one on the other, heading into single pipe then two regular sized cats before the muffler at the back just in front of the rear axle.

 

Holy **** 5 cats! Are these prone to go bad because I am thinking my truck is not worth the fortune that it would cost to replace them?

 

Well, pre cats aren't going to cost the same, however i'm fairly confident that you don't need them for emissions, they're designed for cold startup emissions.

And yes, it does seem Ranger cats go bad and collapse, keep seeing threads posted where they're getting really blocked.

Short version, if i had a problem with the 3 pre cats, i wouldn't replace them, just remove them.

 

ok thanks. Hope I don't have to mess with them as they look like a pain to get to.


Took a quick look at brake backing plate on driver side, I saw some shine stuff there, either I did not scrape it clean enough or the new seal is leaking which means new axle likely. I will keep an eye on it.