economy

[big rig]

Hi, I just bougth a 92 7.3 non turbo crew cab;however, the mileage per gallon "sucks". What can I do to increase milleage and performance out of this engine. I love my truck and I will like to keep it?
Thanks,
Big RIG

 

[nyteshades]

Define sucks. What transmission do you have, what size tires, and what's the gear ratio?

 

[big rig]

The tires are 235/85/16. The rear end and transmission are stock;However, I do not know what tranny or rear end was stock for that year(1992) I imagine is the E40D? I just know, the tranny shift good and it has an overdrive.

How about the air filter, do you think a ram air or an aftermarket filter will also help? Right now, I took out the plastic part that goes into the from between the hood and the radiator.

 

[Diesel JD]

Hey Big Rig. Typically the reason fuel economy sucks is the fuel injectors are bad, the injection timing is too far advanced or retarded or the engine is weak, lots of blowby, low compression or the driver has a lead foot. Also what are you expecting out of this thing in terms of fuel economy? I'd say 14-16 in town and 18 on the highway empty are reasonable and you may miser more out of them if you go in that direction and aren't in too big of a hurry to get where you're going. It'll never be a TDI or a Prius, and it may never hang with a 12V Cummins, but you should not be in the single digits unless you're beating it really hard or pulling extremely heavy. Mine has always been 12-16 except for a few times when things were wrong and I got a little less and a few other times when everything was perfect and I was fortunate to get 16+. I have no overdrive fwiw. If you ever come up to N. Florida I have the tools to set your timing to spec.

 

[LCAM-01XA]

Automatic with overdrive is an E4OD yes. Your rear gears are likely 4.10s seeing how you have a crew cab. What fuel economy numbers are you getting now, and where and how you drive? For instance my dually can pull steady 20 mpg on the interstate, but I have to be driving at 1900 rpms (about 55 mph, give or take some). Then once I'm in the city it immediately drops down to 12-13 mpg, and if I drive through an area that has lots of hills and lower speed limits I don't expect to see anything over 10 mpg.

The air filter thing - bigger is better yes, generally, but the way you have your intake now without that plastic pipe you're sucking in hot air from the engine bay, which will hurt your power and probably your fuel economy as well. What many of us have done is grab some 8ft of 4" aluminum ducting for a household laundry drier and run that from the air filter box to somewhere where it can pull clean cold air - I chose an opening in the firewall that is under the driver-side battery, so essentially my intake sucks in from behind the bumper.

 

[big rig]

Yes, that was exactly what I was expecting from this rig with those figures that you posted. However, I think, I am in the single digits like 8 or 9 empty? Yesterday, I put 10 gallons of diesel and I only got 92 miles from it. Now, I just bought the truck last week. I just put new heads because the heads were crack, I guess the former owner let it overheat.

Now, besides new heads, I put new glow plugs, glow plug module sensor, new radiartor and flush the filty warter that it had with antifreeze.(no water). But I did not change the fuel injectors and I did not time it to specs. Maybe that is the problem.

 

[big rig]

How can I tell if the injectors are bad and how can I put it in timing?

 

[Diesel JD]

Well when you were fixing the engine problems did you take the gear cover that the injection pump attaches to off? If you did sometimes that gear can jump timing. If not then timing should be attainable by simply rotating the pump. Timing by ear is really hard even for experienced diesel guys who can miss by a couple degrees even with lots of experience. Timing by ear is tedious too, as it probably takes two or three tries to get it right. The best bet is to find someone here with the tools, I'm up here in Gainesville and would be glad to set it for you at no charge and Dennis 77F250diesel is in Tarpon Springs and probably would be willing also. I know that is a far piece. You sound like somebody who has good mechanical knowledge and likes to do their own work so you might look into the proper tools. The best deal is probably a Ferret pulse timing adapter because it is a stand alone unit that can plug into any adjustable strobe timing light. It does pulse timing and for that the book spec is 8.5* BTDC at 2000 rpm +- 2 degrees. With this new ULSD and with biodiesel at higher blends 9.7*BTC seems like a good number. You can get the old luminosity tools snap on MT1480 or 480 on ebay and others, but the replacement parts are hard to come by and Snap-On no longer supports them. A lot of guys here know more than me about these tools but I'd be glad to share what I do know, PM me your number if you want to talk about it. If I can't tell you what you need to know I can probably direct you to someone who can. As far as the injectors, any good diesel shop should pop test them for cheap or free. You're looking for a nice narrow cone spray pattern and at least 1800 psi of pop pressure, all nozzles within +-200 psi though +- 50 is ideal. You should have a few good fuel injection and turbo shops in the greater Miami/Ft. Lauderdale area so shop around. Some of these places may also time with tools but you need to ask and be sure if they do and what method they use. If it is determined you need new fuel injectors you can get remans on ebay all day long for $100-150 for a set, or for a little more you can help another OB member out and get very nice new ones with a guy who'll stand behind the product from Typ4. Don't be like me and get burned for $40 each for new ones at a local shop(kicks self in butt) but he had me over a barrel, truck in my sig is my DD and 7/8 of my injs were bad... I watched him do the test and it was no lie!

 

[gonecrazyi]

Hey Bigrig, were you the one that came up and bought a set of heads off of me a few weeks ago?

 

[big rig]

yes

Hey going crazy!!! its me ERIC, I bought the heads from you. Thanks man, you save a lottt of money. Hey, you told me to ask you in detail how you mix the oil with diesel and the filters I need to buy to do it right. Tell me, what do I need to buy and where?

 

[big rig]

I have no idea of that piece that you are talking, but I' am sure going to ask the mechanic here to see if he move it. Of course, I will like to go and visit you with my new rig. Its old, but I LOVE THAT GROAM of my diesel engine. Everybody has to turn their heads and look twice to make sure is not a SEMI because it is LOUD!!!!
My number here in North Miami is: 786-286-8012. My name is ERIC and I always love Diesel trucks, but everybody discourage me of getting one until now, and I love it man

 

[big rig]

Send me your telephone number, maybe you can give a guide on what I need or where to get the stuff because its true. A new Injector cost $39.95 each in the autopart. What a rippoff!!! I definately want to put my old rig in shape so all the help will be appreciated. Thanks for the info a it help me a lot. Once again, thank you my friend.
MY email is: [email protected]
THANKS

 

[gonecrazyi]

Contact typ4 about his injectors, he has great products and stands behind his work.

http://oilburners.net/brian/idi/FuelInjectionServicing.htm

Check this link out.

 

[fields_mj]

You may also want to check the wheel bearings, but with the millage you are talking about, it would be more than just bearings. If you have the owners manual for the truck, you should be able to look at the numbers on the sticker located on the drivers side door and then look that up in your manual to find out what the differential gears are (or were originally). Originally, I was getting right around 16 with my truck. New wheel bearings, swap from 4.10 to 3.55 gears (and new seals and bearings), alignment, and Auto RX treatments and I'm now around 18.5 mpg. I removed the soup bowl 2 days ago, so we'll see what that does to my millage. Next thing will be to go back to stock tires. I'm hoping it will push me up over 20.

With what you are describing on your truck, I would probably start with what everyone else has already stated, injectors and timing.

Just my 2 bits,
Mark

 

[big rig]

THANK YOU

Definately I am going to check the injectors and the timing first. Them, I will check the rear end. Later, I am going to try to get a good air filter or improvise one so the truck can breath better.

Once again, thank you for your info and will keep in touch.]
Thanks