I know this has probably been answered but I searched through old theads and couldn't find it.
I have a 89 W350 all stock but the strait pipe and K&N. I am running on 235/85/16 with a 3.07 ratio and a auto trans.
The best that I have been able to get is around 14.5 mpg. I would rather drive this than my 94 Dak. that is getting a best of 16mpg. But if I can't improve the mileage the wife will make me park it. I have seen posts that say they are getting 18-20mpg. How can I get it? I would also like to make some upgrades (turning up pump?) to get more power and still get good mpg's. Any help would be great.

 

Hi,
Get rid of the K&N and bump the timing 1/8 of an inch. I had a K&N and got rid of it because it was really messy. I noticed that I had a lot of black yuk on my turbo intake blades with the K&N.

Hope this helps,
Mike

 

Thanks. Is there a link in the tech dept. that will explain how to do the timing I don't want to waste everyones tome by asking ?'s that have allready been answered.

Ryan

 

I'd do a valve adjustment too, if you haven't already.

 

I haven't done anything yet. I wanted to get some input before I did anything. Thank you, I just printed out the instructions on how to adjust them.

 

How fast do you run, and how much pressure do you run in the tires? The 3 speed trucks are very speed sensitive, if you run 70 your mileage will suck, but if you back it down to 60 it will do much better. Run the tires as hard as you can stand 'em, tires make a big difference in fuel economy.

 

I run the tires at the rated psi on the tires and on the last trip (300mi highway) I was running at the max of 65mph. thanks Ryan

 

Running a bit slower will help, as will the timing bump. Instructions here:

https://www.dieseltruckresource.com/...50&postcount=5

edit---Welcome to DTR Nice to have you along
I'm just up the road in Binghamton, as is Cowboy_Customs. I bet you and Wannadiesel are practically neighbors

greg

 

Greg,
Thanks for the link I think I will give the timing a bump. How far should I go with it.
I hope to find someone close that I might be able to meet and possibly get some good info and ideas from.
Thanks for the warm welcome
Ryan

 

Ryan,

Most folks separate the factory marks by 1/8''. I've had them separated by a lot more than that, but the 1/8'' produces the best daily driver manners, IMO.

How far south into PA are you?

 

Thanks I will do the 1/8 as soon as the weather permits (no garage). I am about a hour south of pocono raceway and about 40 min north of Upper Bucks County

 

Thats not too bad, yer bout in the middle of G1625S (Greg) myself, and Wannadiesel (dave) Thats sounds like a baddd rig, dually?

Welcome to DTR! Make yer self at home, just keep yer feet off the desk!

Check the threads for the meet in KY June 9th, Greg and myself will be heading down, tryin to work on Dave, and a few others. Im trying to arrange a little (or big) 1st gen convoy that friday morning.

 

Hey Free89W350, I hadn't noticed you were in PA! Sounds like you're a little over an hour North of me, give me a holler if you need help with anything.

 

Thanks Dave I might have to take you up on that. I am originaly from Ottsville and still have alot of friends and family down there. I have been down in your area quite a bit. I've noticed that you have helped quite a few people out here at DTR. I hope some day I might meet up with you and get a few pointers. Ryan

 

hey free89w350, i have a 90' 4x4 with the auto and the 3.07 gears also, before i lifted it and did the motor swap, i saw a best of 15 around town and 17ish highway, also iturned my pump all the way up and it did not affect my mileage at all, some truck vary though, also before my 4inch lift i put the 33inch muds on first (had 30's on originally) and i swear my in town mileage and highway improved from runnig a taller tire, but after the lift the best was 14, basically everywere. oh and getting a tighter torque converter will help a lot. also if interested you can help it shift a little firmer which will help the auto trannys life and reduce slippage, just PM me for more details

jason