loss mileage

[GDollenger]

Ok, I know this has been beat to death here but I know my truck and I know something is wrong. Let me give some history and tell me what you think.



I have an 04. 5 4x4 auto trans and 4. 10 gears. This is my 3rd diesel over the last 10 years so not new to diesel either. I have had this truck for 3 years and it has 55,000 miles. It has always netted me at least 19mpg on the highway with as much as 21. Over the last couple months it has went from average 20mpg on the hwy down to 15 now. I am only getting 12 in town when I used to get 16. I use Stanadyne every other fill up, and keep my Smarty Jr set on level 2 all the time.



I have been noticing the "ticking" sound from the drivers side of the truck. Not real load, but noticing it more and more. I took the truck to the dealer and told them what was going on and the technician had it all day and said nothing is wrong. He said he ran a diagnostic and there are no codes so there is nothing he can do. He said the only explination he could find is my 285's are the reason I have lost 5mpg!



Please tell me, is there something specific I can have the dealer or a diesel service center look for to tell me everything is ok or not? My instinct is telling me that this is an injector issue. One thing for sure though, this is not normal for my truck, so what should I do? Thanks to you all.

 

[VanOverbeke]

Come to Clovis New Mexico and I will fix it with your money.

 

[GDollenger]

Thanks for the help bryce... . but bribing me with MY money won't get me to move to NM!



Anyone out there got some insight on this? One more thing to note is that I really haven't noticed any loss in power either. Just really bad mpg numbers. Thanks!

 

[WoodChuck]

How's the oil level doing? Sounds like a bad injector to me too. Chances are the tech just looked for codes and didn't see any and called it good. There are two more things he should have done, one is the cylinder contribution test (power balance) and two is he can selectively take one injector at a time out of the loop to see which is the noisy one.

 

[sweeda]

an infared heat gun pointed at each exhaust port after the truck has been driven to get it all warmed up may tell you if you have an injector over fueling. The temps will not be exactly the same but one that is not close to the others is the bad one. The other thing to check is the trans. you could be slipping a little in one or more gears or the converter may not be staying locked up. Watch you rpm at all shifts and on the hiway and see if you get a change in it. And then there is the maintainance items fuel and air filters. living in cal. I've noticed that the weather has a lot to do with fuel economy. cold will make the fuel heater and intake heaters stay on longer and can effect it also, Have you changed your fuel station It could be a weights and measures problem Maybe these ideas sound dumb but you got to start somewhere. Try to put smarty back to stock & drive to put some miles on it and return it to your regular setting sometimes the ecm will try to fix it. 5 mpg is alot. let us know what you find. my 04. 5 auto, 4. 10 285/70/17 2 wheel drive NEVER got the mileage that alot of owners claim. my best was 18. 5 mpg on an 1600 mile round trip. Daily average on my normal route is around 15 mpg

 

[GDollenger]

Thanks for the inputs guys, these are the things I was looking for. WoodChuck, you are exactly right when you said the tech only looked for codes. When I asked if he went any further, he said that they would not go any further because there were no codes present. As for my oil level, all seems normal there. I haven't noticed any "extra" in there.



When it comes to the normal maintenance issues, my S&B air filter was just cleaned about 3000 miles ago, and my oil was changed in September with a fresh batch of Amzoil. My transmission was serviced last summer, about 11,000 miles ago, again with all Amzoil. I also did the front and rear diff at the same time as the trans again with Amzoil fluid.



I always hand calc my fuel mileage and have definitely lost 4-5 mpg all around. I returned my ECM to stock last week before going to the dealer and have not reprogrammed it back yet. I can honestly say that the injector "ticking" is not as noticable now, but I filled up today and still only got 12. 8 mpg this tank with combined hwy and city driving. Normally that would be about 16. 5. Something isn't right... .

 

[WoodChuck]

I like Sweeda's idea of using a infrared thermometer, have you tried that? Have you noticed any smoke on startup or any other time, white, black or blue?

 

[GDollenger]

I have noticed an occasional small puff of white smoke at start up. But not at every start up, usually in the morning after the truck sits for the night. As for the thermometer, I personally do not have one, but it sounds like a great idea and will look into borrowing one.

 

[JimB1]

Try running couple tanks of Biodiesel which will solvent clean entire system and big increase in lubricity for injectors and CP3 pump.



Start with 2 tanks B-20, change fuel filter (7 micron), then couple more tanks of B-50 or B-99, change fuel filter again.



Maybe carry spare fuel filter & wrench (1 1/8 socket).

 

[WoodChuck]

Be careful with Bio-diesel if it gets below 30, it gels at a higher temp than #2. This can be remedied by blending with #2 and using additives but higher concentrations and low temps won't work.

 

[RSlater]

Although I haven't noticed a ticking sound, my mileage appears to have dropped significantly too. I used to get 18-19, but now I can't squeeze anymore than 16 (trying very hard to optimize mileage). I've owned the truck a little over a year, and I've only got 39K miles on the truck. Yes, the temps in my area have dropped and winter fuel may be a factor, but something seems wrong. I used to be able to get an indicated 24 mpg (19 actual) on the overhead, but now I can't get beyond 22 indicated (16 actual). Interestingly, when I used to get 18 actual, the overhead indicated 22 mpg. Also, I used to run biodiesel, but the drop in diesel prices doesn't make it cost/time effective to use bio right now. In my former 01 truck, running bio would cost me about 1-1. 5 mpg, so I don't believe running bio provides a mpg improvement, but I do like the added lubrication and lower price as diesel skyrockets (which is sure to happen again!). Besides, it's too cold right now to run anything greater than B20. Perhaps I should run some injector cleaner or some bio through for a cleaning? Performance hasn't appeared to suffer, but I can't really let loose with the Smarty due to a stock transmission, so I typically run on 3 (although I've tried 5). I'm currently running REVO with timing on 4. Maybe it's just winter fuel and conditions?? I haven't taken it to the dealer, since I've never trusted them completely and they generally seem to take the "I couldn't find any codes" approach without heavy prompting for deeper digging...

 

[SShafranko]

Maybe lift pump going?

 

[RSlater]

I kind of doubt it since 06's don't seem to have that issue predominantly. I'm suspecting an injector/pump leak?

 

[ANG012]

When they switch over to a winter blend diesel my mileage on my 97 & 03 drop about 2-3 miles to the gallon. In the summer it goes back up. When did you notice the drop in your mileage.

 

[RSlater]

It did seem to correspond with the winter season (fuel blend?), but I was expecting a 6-10% drop and this is more like 20%. Then again, I've been a bit disappointed by the truck's mileage overall (I know it's a MEGACAB), especially when I read of others' claims of 20+. Yes, it's got a 3" lift with 315s, but @ 55 mph it's only running at 1400 rpm. The last time I towed (7500 lbs), I only got 10 mpg and I kept it around 65 mph. Maybe I just got spoiled with my '01 that got better mileage, but I want to make sure my truck isn't experiencing a problem that I'm not aware of since I've only had it a little over a year...

 

[WoodChuck]

What gear did you tow in? The HPCR is most efficient at 1900-2100 RPM. With no load 1400 is probably ok but not ideal.

When I do mileage checks I set the cruise at about 60-63 MPH at a time when I know there is no traffic and hit the highway immediately after fill up and do a out and back trip (141 miles) just for checking mileage. I start close to home and and cruise to Santa Barbara and back along the coast with rolling hills and one moderate grade in Camarillo. I do this after any significant change to the truck. Last time was a couple weeks ago after I got my new 35" AT Toyos and I recorded 21. 9 MPG. The best I've ever seen is 23 MPG over 277 miles driving from Pahrump NV to L. A. CA with the truck totally stock. But I don't consider this normal driving. Normally I see 15 - 17 MPG. and as low as the 14s, I have a pretty heavy foot most of the time.