I posted this in another forum and was given a smart **** reply and directed to try here.

I have never had a diesel vehicle before so any help is appreciated. I have a 1990 F250 7.3L diesel with either 115000 or 215000 miles. It has the manual 5 speed close ratio (Z-F) transmission and the 3.55 rear end. I will be using it for noral driving and to tow a 27ft travel trailer.

What kind of gas mileage can I expect?

Anything I can do to improve my mileage? (besides driving nicely)

Any fuel or oil additives anyone recommends? (I looked at AutoZone and everything said for cleaning fuel injectors which I don't have)

I really do not know a whole lot about the history of the truck. I had the oil changed today (cost me $55). Normally I would get a tune up and filters changed but I guess without spark plugs/wires that kills most of the tune-up part. Any other maintainance I should do?

Any other tips for my first diesel?

 

Ok we use Diesel Fuel so about 14-20 MPG if the injectors and IP are in good shape.

Ensure the injectors and injection pump are in very good condition (how old are they), also have timing checked........

For best performance use a fuel additive Stanadyne or Power service, keep fuel filters changed at regular intervals, only use best quality fuel from reputable suppliers.

Who did the oil change and what oil did they use, we use diesel rated only ie Shell Rotella 15-40 (from Wallymart) oil filters.. most use the PSD filters Motorcraft FL1995 (add one extra qt with PSD filters, total 11)

Check the A/F for SCA's (supplimental cooling additives)

Go to IH ask for the Fleetguard 3-WAY Coolant Test Strips CC2602B contains 1 Test strip.

They show A/F freeze point (EG and PG coolants), Nitrite level and Molybdate levels. Test the coolant (cold) check the reading, if top up is required IH will have DCA4 or Ford will have VC8........... (SSDD) If you feel really energetic you can change the A/F and start fresh. Ask more questions re how to for the A/F change later..........

 

themtb,
Welcome to FTE and the IDI diesel forum.

Was the other forum here at FTE?
Normal driving you should be in the very high teens or low 20's with that gearing.
Towing, a 27 foot travel trailer catches a lot of wind. I am going to guess 10 to 12 MPG depending on the terrain.

Driving style will have the largest affect on your MPG.

Diesel Kleen is a good thing to add to every tank of fuel. Keeps the injection pump and injectors clean and lubed.

Oil change every 3000 miles, use a good diesel rated oil and filter.
Air filter, I change mine every other oil change, but I am in a lot of dust with my truck.
Fuel filter I change about every 12,000 miles, but I only buy fuel from one high volume dealer and have never had any trouble with the fuel from them.

Come back often, there are a lot of knowledgeable people here that can help you with any problem you may have.

 

all i can offer is just make sure you wait to start.

i've seen more people than i can count just hop in a diesel and crank the ignition.

 

Yes, it was a forum here.

As I said in my post, I don't have injectors. After reading the forums here I was under the impression that none of the diesels had injectors until a few years later? When I went to change my air filter it looked like a regular old carb set up to me.

So what good would Diesel Kleene do me for $6/bottle?

How hard is it to change the fuel filter? I was looking at it right there on top of the engine. It looks like it would be pretty easy but there are a lot of hoses coming out of it and I certainly don't need diesel all over the engine.

 

The Indirect Injected Ford Diesels use older style manual injectors, you are probably looking for something with wires. Your truck has a manual rotoary Stanadyne Injection pump with individual high pressure fuel lines feeding the individual injectors. Just look for all the grey steel tubing on top of the intake manifold.

Since the injection pump and injectors are mechanical devices with lots of moving parts they can easily gum up with dissolved impurities in the diesel fuel and stop working properly. The Diesel Kleen removes these deposits and lubricates all the moving parts. Spending a few $'s on Diesel Kleen is a lot cheaper than replacing the injetion pump and injectors.

Changing the fuel filter is not to difficult; however if you are not familiar on how to air bleed the fuel system than it may be best left to a professional mechanic.

 

Another thing Diesel Kleen does is lubricate the injection pump and injectors.
Back in the day when these engines were manufactured, there was a lot more sulphur in the fuel.
The sulphur acted as lubrication.
Todays fuel has low sulphur content and it is going to get much lower in or around July this year to meet new Federal regulations.

About changing the fuel filter.
First you need a filter, I use Purolator F54692 fuel filters on mine, available at Advance Auto or Autozone.
Should be about 20 dollars plus tax.
It is not hard to do, but it can be a bit on the messy side if you make a slip up.
On the 90 model there is a drain in the bottom of the filter and a wire that goes to the bottom that needs unhooked.
The drain screws into the the filter to open the drain.
You can drain some of the fuel out of the filter into a can.
Then unscrew the filter from the bracket carefully.
After you get the filter out of the truck, drain the rest of the fuel into the can.
Then you need to remove the bottom part of the filter from the cartridge.
Properly dispose of the old filter and fuel.
In the filter package you will have new O rings for the top and bottom of the filter cartridge, lubricate the bottom O ring with some clean engine oil and install the bottom.
The top O ring is then lubricated and the filter is filled almost completely full of either Diesel Kleen or fresh diesel fuel.
Now reinstall the filter.

When I do mine, I assemble it hand tight, then tighten each part about 1/4 to 1/2 turn more.
Start the engine and hold the RPM at about 1500 till it runs for a minute or so. That gets the excess air out of the fuel system.

A couple of rags to clean up any spills are a good thing to have handy when you do this job.

About the other reply you had,
You will find the other forums do not know many answers about your truck.
All diesel 250 Ford trucks are heavy duty trucks.
The frame and axles are the same as a 1 ton.
The decoder he pointed you to don't work on your truck.
They have no idea about fuel mileage and the gas mileage will not be close to the same.
There is also a bit of jealousy, envy, resentment or what ever you want to call it at times between the gas and diesel owners.
I have no idea why, but that is the reason I post in several different diesel forums, every once in a while in the towing forum and the biodiesel forum from time to time.
Those other forums, I have never been in most of them.

That is also the reason that although we should only be doing engine specific topics in this forum, we do the entire truck right here. All it has to have is an IDI diesel engine.
We even helped a guy in Norway that had an IDI diesel in his boat.

That guy had no clue how to answer your post, he tried to point you to the answer.
To bad his answer did not take you anywhere that had any of the info you were asking.
He had a 1994 F150, so nothing was the same as your truck.
Also trucks after 92 roll over at 1,000,000 miles.
Trucks before 92 roll over at 100,000 miles.

I am not making excuses for him, but he had no idea.
Come here for answers, someone in this forum knows every inch of your truck inside and out.

 

Would changing my 4.10 rearend gearing improve mileage a bit?

 

Going from a 4:10 to say a 3:55 will help your milage. I would estimate anywhere from 1 to 3 mpg.

 

I have a 92 F250 7.3 with a 5spd manual with 4.10, if you go to 4.10 you will diffenately notice a difference in mileage. I don't suggest it unless your going to be towing alot.

 

I think ya miss-read, I already have the 4.10 gears sla3492. I hope to adjust to 3.55 gears but we shall see...