Fuel Economy Drop??

[RSchwarzli]

Hey all, over the course of the last few months, I have noticed a significant drop in fuel milage on the 90. According to my fuel logs, I was getting about 20 MPG when I did my detail MPG study 2 years ago (that was on summer blend), and now that has dropped to about 13 MPG!#@$%! Last summer, with ULSD being served, I did notice a small drop but now, especially with the price of diesel... .



I was originally thinking it was due to winter blend, however that should be out of Sunocos tanks by now (it is a busy station).



Is it possible that such a large drop it is due to ULSD? Would the motor de-tune itself that much over the winter (the motor has not had a good tune up in a few years)? What if the trans was slipping (although I do not believe this to be true as the temps are normal and I have had no issues)?



Any thoughts?





Robert

 

[Tippin Spotted Cow]

I have this theory that its a big conspiracy, and to make up for the $125 a barrel, oil companies are adding to their fuel with things like saw dust, maple syrup, diet coke, and sewage runoff to produce more diesel out of less oil.



I hope you understand I'm being sarcastic.



I, too, have noticed the drop in economy in my truck, and in order to blame it on someone other than myself, I came up with the afformentioned ridiculous theory. My truck has had a couple things turned up, and the transmission is acting up real bad, and that's whats keeping me from doing an all out exploit into what the real issue is. Also my odo doesnt work... that makes it a little harder.



Here's the thing, I know my truck. I drive my truck, alot. I am one with my truck. Regaurdless of the reasons listed above, I know that it's not getting quite what it should as far as fuel economy goes. In all seriousness, I completely agree that somethings up. It's just hard to investigate considering all the changing variables involved. They really could be screwing us over somehow or another at the pump and we would have no clue. I guess if you can find anything out, let me know... . let all of us know. Until then, saw dust and sewage.

 

[PToombs]

Run the valves, and get the injectors pop tested. It could be as simple as that.



Sawdust and sewage. I think you've been smoking some.

:-laf :-laf



(I believe the maple syrup and diet coke )

 

[RSchwarzli]

Thanks! I will look into that. It would be nice if that is all it was... .



Robert

 

[blacksheepdiesel]

Air filter?
Fuel filter?

Right foot?

Godspeed,
Trent

 

[Bob Beauchaine]

I just made a run from Portland OR to Meridian ID last weekend. This is a trip I usually make twice a year. Last May I saw 20. 77 mpg for a 916 mile run at 70 mph. In August I ran 22. 45 for 1005 miles also at 70 mph. This year I thought I would try the trip at 65 mph and got 22. 71 mpg. If you compare May to May that is almost 2 mpg more driving 5 mph slower. If my fuel loan is approved I will see if August is any different. ULSD seems to have had only a minor effect on my mileage. My city average is still about 17. 5 winter and 18. 5 summer. Look at my sig for mods.



Bob

 

[Grey Wolf]

If my fuel loan is approved

Bob

Ha, now isn't that the truth



Good one Bob, You know it hurts so bad it's funny, Oh well what are we to do... ... ... ...



GW

 

[RSchwarzli]

Air filter? - new

Fuel filter? - hmmmm, It is old



Right foot? - no change



Robert

 

[JLEONARD]

I also have not seen a mpg change...

 

[R C Cola]

Miliage change

I was seeing a slight drop in miliage compared to a year ago and after having the injection pump gone thru (broken spring) the miliage has come back up. Also noticed I gained back 4 pounds of boost that I had lost over time hmmm... broken spring in the pump ?

 

[RSchwarzli]

OK. What gives!! I am so confused now!



I changed my fuel filters as suggested and now I am seeing consistent 20. 5 MPG! :--) What gives! Everyone I ask says a fuel filter should have no effect on MPG!



Is this a diesel thing as I have never seen this on a gasser? Also, what is the technical reason for why this works? My mind tells me a clogged filter should reduce the amount of fuel to motor therefore the motor burns less. Apparently I am wrong!



Thanks!



Robert

 

[Tippin Spotted Cow]

Cleaner fuel will burn more efficiently, and therefore require less to put out the same amount of power. Thats the only theory I can come up with. I hope that you take down the average over multiple fill ups and not just get the numbers from one tank. Too many factors come into play if you dont consistently take down the numbers for many tanks.

 

[dpuckett]

It has to do with improving fuel flow and reducing restriction. It is a known fact in the diesel world that one of the first things to check after getting poor MPGs is the fuel filter, or more properly, the inlet pressure to the injector pump (which is hurt by the clogged filter).



DP

 

[PToombs]

If the filter is clogged, you don't get enough to fill the IP. If you don't have enough, you can't get good pressure at the nozzles, resulting in a poor spray. Poor spray = less power, which means you are on the pedal harder to go the same speed. Basicly, you aren't getting all the power out of the fuel if you don't get enough, so you use more.

I know there is a better way to say this, but you get the gist of it, I hope.

 

[Bluebird]

Average mpg's...

I continue to average 21mpg with the range of 19 to the high 24's. I get on the freeway and set the cruise at 64mph, I only goose it when I have to. I'm easy on 'er until she's warmed up. I drive the surface streets Grandpa style :-laf (Got 1 grandson now... ). That's my $. 02.



Happy Independance Day to All fellow Patriotic Americans

Patrick.

 

[RSchwarzli]

Thanks guys! That makes sence (it also makes cents )!



Yes, that is based off of 1 tank, but that is all I have to go off of so far as I have not gone threw 2 yet! As for the previous 13 MPG, that was over many tanks. Either way I am up MPG!



Thanks again! I just payed for my TDR subscription off of 1 tank!!



Robert