Does anyone have a place for me to start looking to try and get better mileage. I am currently getting about 9 -10 mpg . It is a 1994 f-350 non turbo, E4od, 4x4 mason dump with L-pack toolbox (longer wheelbase)and I believe it has 4.10 rears as it will be traveling 60+mph @ 2000rpm?

It only has 54,000 miles and was previously owned by a local town. Have been using power services in every tankfull.

Climbing hills I see black smoke from exhaust but I don't know how much is expected?

This truck is expensive to drive with no load on her and I can only imagine what kind of mileage I would be getting when loaded?

Any info would be great.

 

Well, One thing you can do is get a biger exhaust diesels love free flowing exhaust so either get a straight through style muffler or no muffler at all. Another thing you can do is run some diesel kleen its the best stuff out there in my opinion!! Also a turbo can help with the milage but mostly with power and torque. AS for your black smoke, thats just un burnt fuel burning off in the exhaust, a little is ok but if your getting massive clouds(SOME GUYS LIKE) then you might have your ip turned up too high, wich is an easy fix. I dnt really know anything ealse thatll help u cept for maybe keeping the foot off the pedal a little!

 

Bassproguy,

Thanks for the info, I think Walmart sells that dieselKleen, I will go over and get some and start there.

Thank you,
Paul

 

Wallymart sells Power service too, you can chose. The timing may be too far advanced or as stated above fuel may be adjusted too far.

You need to line up the scribe mark on the pump flange with the scribe mark on the pump gear housing. That's essentially it to start with. Hopefully the gear housing hasn't been removed, 'cause if it has it is possible the pump timing gear has been moved, and it is very difficult(but not impossible) to get it back to the right spot.

On the housing that's mounted on the top front of the engine where the pump bolts into, There is a small line about 1/4" long stamped into the rear/upper face of the housing just where the pump would mate to the housing. Likewise, on the pump almost at exactly the same spot on the flange of the pump where it bolts to the housing is a similar line scribed into onto the top of the pump flange.

The idea is that when you put the pump into the housing on the engine, and if you have those two marks lined up such that the almost form one 1/2" Long line, then the timing will be close enough that the engine should start and run. This is known as static timing.

Dynamic timing via luminosity is done where a probe is put into the cylinder, and actually sees the light from the explosion of the fuel, and the timing is set accordingly.

Some of us set the timing by "ear". This comes from some experimentation and experience.
I like mine so that when the engine is cold, as the cold advance is on, the engine rattles pretty loud, but once the cold advance drops off, then the rattle smooths out and the engine is much more quiet. If you have it too advanced, then it makes that loud rattle all the time, often accompanied by lots of black smoke, and if too retarded, will sound kinda flat most of the time, lack power, and often not smoke at all, or may even smoke greyish/whitish(unburned fuel).
When you are standing at the front of the truck facing the engine, if you turn the pump couterclockwise(top of the pump to the passenger side) you'll be advancing the timing, and obviously clockwise will retard the timing.


Zigg

 

PLC7.3,

I really appreciate the explanation of the IP adjustment at a level that I could understand as I am relatively new to diesels.


My truck starts right up with a single glowplug cycle, runs great but a little weak in the hills and just not the best fuel mileage. I will keep running the fuel additive because one tank full I believe I got between 13-14 mpg, but it was just one time.

Maybe there is gunk in my IP from just driving around town for 54,000 miles and not getting it out on the highway.


Do you think I should be getting better mileage? I drive like an old lady, very easy on the pedal?

thanks,
Paul

 

Paul,
There are a lot of mods you can do to the 7.3 to gain milage. From the descriptions you give I suspect there is room for improvement on your truck.
Open up the intake to a full 4". Open the exhaust (yes, it should help even if you aren't running a turbo.
Install a turbo.
Open up the muffler and exhaust to 4" and straighten out the pipe.
Install a propane boost kit. (haven't done this one my self but it's tempting)

 

Tdford,

BY opening up the intake do you mean, the ram air and cutting out the dome in the filter housing? Also I have thge stock filter with prefilter sponge wrapped around it, should I remove this and get a K&N filter?


And as for exhaust, my muffler guy said he could get me a 3" exhaust and muffler for my truck. If I wanted to go to 4", what kind and where do I get it?


Thanks,

 

Sad to say you are not going to get much better than 11-12 with a truck like that my IDI F-450 never got better than 12. My truck weighed around 8000lbs empty which is what your truck probably weighs. My truck had 5:13 gears so the engine didn't work too hard but your truck only has 4:10s so your engine is working a little harder. With your empty weight being so high your running around with a half loaded truck.

You could probably look into changing the injection pump and injectors if they are factory originals.

 

TD Please explain what you mean by the intake, id like to know myself

 

Being that the previous owner was a city. Probably the engine has a lot of hours on it. Might want to have injectors pulled and tested for proper operation. Sounds like the injectors are putting out a solid stream of fuel instead of a mist.

 

Kenworth and Bigredtruckmi,

Thanks for the info, I will check out what both of you said. I think you guys are on the right track about the injectors or IP because when I was driving on the interstate today I got a huge puff of excessive black smoke when I punched it to the floor at about 65 mph. I wanted to see what would happen.

Thanks,

 

Depending on the turbo intake location reduce the bends and restrictions as much as possible.

First make sure the intake opening matches the turbo. The filter housing for my turbo has a full 4" round opening but the stock intake necked down over the battery to measure 1 1/2" X 7". That 4" round opening = 12.5 sq. in. The 1 1/2 X 7 " opening = 10.5 sq. in. Obviously the turbo wasn't getting the air it was designed for so I changed the intake to 4" X 10" and then necked that down to 4" round. If you can install the intake so it acts like a ram at highway speeds you'll increase the air flow more.

The second step it to streamline the intake tube. Anything that interupts the flow of air will reduce the amount delivered to the turbo. A smooth straight tube has the least resistance to air flow. Flexible hose has 3 times as much resistance as that smooth tube. A 30 to 45 degree bend has the equivalent affect of adding 3 feet of duct. A 90 degree bend is the equivalent of adding 6 foot of duct.

Third, use the least restrictive filter you are comfortable with for your operating system. I personally run K&N filters but my driving is 98% highway.

Note: this same logic applies to opening up the exhaust. Use a flow through muffler, reduce the bends, and shorten the run as much as possible to help that engine breathe. I noted a big improvement going from 2 1/2" to 3" and another notable milage improvement when I got rid of all those bends over the rear axle. (The bends in the 3" pipe actually reduced the net opening to about the same as a 2 1/2" pipe. Insist on mandrel bends which will help keep the original size passage through the pipe.) I haven't upgraded to 4" yet but that's my next planned change.

These 3 combined intake changes coupled with an efficient exhaust system will maximize the amount of air your turbo can provide which will affect how efficiently your engine is burning the fuel you give it. More efficiency = increased milage.

My empty truck weighs over 8,000 lbs. and has a 4:10 diff. I seldom run empty but my last 600 mile empty run was at 16.7 mpg. With another 5,000 lbs of camper and gear I still get about 13 mpg. Add another 5,000 lbs of horses and trailer and a few mountain passes and she'll run in the 10 to 11 mpg range. I keep good highway records so these milages aren't guesses but are paper and pen calcuations.

 

Well TD, that wouldnt do any good for myself or the banshee, see his original post, we both have N/A engines, not turbos so fixing the inlet housing wont do us any good cus we dont have them. Thanks though

 

openign the inlet still will help because instead of having a vacuum on the intake and forcing the engine to suck the air going 50-60 the air will rush right into the engine withthe bigger more stream line air intake. The question i have is where would you run the air intake at threw the core support? I have a 93 f-250 and i cannot find a spot what is behind the grill where i can run a air intake at so it will get the air going threw the grill.
please help!
jimmy

 

Stop and think for a minute here, if reworking the intake helps a turbo charged engine just think what it could do for a NA engine.

I am not familiar enough with the 93 body style to offer much help with a location for the ducting.

As for the 83 model it is the same as mine, I had no trouble getting mine through. I did have to do a bit of sawing metal and a bit of fabrication to make a new top radiator bracket that was above my intake duct.
4"x10" intake = 40 Sq. In.
4" round duct = 12.56 Sq.In.

So there is positive pressure in the 4" round going to the air cleaner when the truck is at speed.