View Full Version : LLY MPG went to POT..!!!!!!!
I was getting 18-19 mpg easily in September. I have noticed a !!!!HUGE!!! drop in mpg. My last 3 tanks(hand calculated) were a measily 11.7, 10.5, and 10.2 all running solo with edge on level 1, around 2000rpm running 70mph(1 gave me the best mpg, I tried all other levels including stock) Edge level 3 netted me 9.7 MPG on a tank running solo.
Winter blend fuel started around here in early October, last year on winter fuel I always got around 15-16 mpg. Could winter blend cause these problems. I have tried different brands, changed fuel filters to no avail......This really hurts the pocket book REALLLL BAd. Cost me $96.34 to fill'r up the last time @ $3.20/gal while Regular unleaded gas is $2.59 :mad: :mad: :mad: :mad: :mad: OUCH :eek:
markrinker
10-17-2005, 03:31
I have noticed the same thing. Must be the winter blend, we are often running into WI so could be burning the same fuel in my LLY.
However, I am noticing towing tankfuls in the 12s rather than the 14s. Do you have a heavy foot, or extended idle times?
rob@rone.ca
10-17-2005, 05:40
I've been getting more like 17-18 on mine in mixed local and highway driving empty, so you WERE doing quite well.
If my mileage went from 18-19 down to 10-11 which is a 43% reduction in identical driving I would be down to the dealer real fast.
Winter fuel should only make at most a 10% difference, (unless they're watering it down!!).
I don't have any idea what would cause such a sudden dramatic change, but it seems it should be checked out. Please let us know what it turns out to be.
Have you tried it with the edge disconnected??
More Power
10-17-2005, 07:35
315's on H2's.......
Bigger and more aggressive tires increase rolling resistance. In addition, not correcting the ECM with the new tire size can reduce real/perceived fuel economy.
Jim
MP, I have had my truck setup up this way since April with good success. The sudden drop in MPG is really baffling me, something is wrong with the truck! I haven't been letting it idle to much as I have been on long trips lately. I've been running it 8-10 hours a day. I don't need to drive it as much now 'cuz I'm home for a while. I guess the juice is coming off and the 265s are going back on, I'll see what that does. If that don't work I'll have to give it to "whitetruck" for a day.
Jim Brzozowski
10-17-2005, 08:04
Buck, with that big a drop in mileage, I'd tend to check the oil level real careful. Maybe the fuel is leaking into the pan via injector leak. Just a thought and I agree on OUCH!!!!!!!
Oil level appears to be at the correct level.
More Power
10-17-2005, 11:26
Generally, the move to winter blend fuel causes a 1-2 mpg drop during the winter months. This is due to a combination of less BTU's in the fuel and more viscous lube/oil/fluids and longer warm-up times. Fuel economy during longer trips and warmer temperatures shouldn't be quite as affected.
We get an occasional report of sometimes drastic drops in fuel economy. I can't explain them, especially if the engine appears to run normally and produces normal power.
Having a boost pressure gauge and EGT gauge can help determine whether the turbo is producing normal boost pressures and whether the EGT is in the normal range for the type of driving you're doing. For example, low boost pressures and/or higher than normal exhaust temperatures would tend to accompany lower fuel economy.
Lastly, the standard recommendation for any engine running/performance problem is to change the fuel filter as a first step. A fuel restriction can produce a range of sometimes seemingly unrelated symptoms.
Jim
[ 10-17-2005, 11:40 AM: Message edited by: More Power ]
I don't think there is any way that the fuel could account for that much of a change. Straight kerosine is only about 20% lighter than straight #2.
I know it's not a plugged cat... ;)
This has been going on since Katrina. It's randomly happening to big trucks as well, all depending on where you fuel. Mine has dropped 5 points, and with the trailer I'm down to 8 1/2. Rumor has it two steps were removed from diesel refining to speed processing, and BTU's dropped significantly, as well as lubricity...T
Tough Guy
10-17-2005, 15:22
What are the geographical locations of the refineries suspected of this?
Thats one way to boost sales when prices are this high!! :confused:
Chris
Buck,
I own an '05 Gmc SLT dually & I'm jealous if you've gotten more than 14.5 MPG. The only upgrade I've got is a K&N filter element & I can only get 14.5 MPG highway & 8.5 while towing a 38' 5th wheel. In North Texas we don't have winter fuels, so that's not my problem. I work for a refining company & can assure you that with all the federal regulations that companies CANNOT shortcut the process wihout getting very costly fines. I've taken truck back to dealer to complain about mileage, they reprogrammed & did'nt help. Changed fuel filter, oil, & cleaned air filter & still nothing has helped. I'm thinking about a different exhaust system & air filter kit. Any suggestions would be appreciated..
White Truck
10-17-2005, 18:44
Buck,
Have you noticed any difference in boost, EGT's, etc. on the Attitude since the problem developed? One thing that doesn't help either is that one tends to not pay as close attention to the values until a problem shows up. Recording the different readings under different driving condions for future comparisons might help. Do that before taking off the Juice for test purposes. If its removal fixes your mileage, great. If not, then we will have a baseline for your truck to start diagnosing from that point.
DKB
FleetFilter.com
10-17-2005, 19:15
I'd be concerned - a drop like that can't be explained simply by bigger tires or winter fuel.
I have Isspro pillar gauges also and I see EGTs are a little higher than normal. Normally, with ambient temps in the 50~60s my EGTs are around 600~700 doing 60 mph. Now they are running 800~900* doing 60 mph.
The ECT seems to be hotter than normal to, the attitude shows them ranging from 196*~208* :eek: doing 60mph with ambient temps in the 50~60* range. The clutch fan kicks on at about 205* I don't have any winter front on either.
Boost seems to be about the same, 2~3 psi doing 60 mph. What would cause a EGT increase especially with winter fuel, a stuck shut EGR valve? I can't think of anything else :confused: Is it possible for the EGR butterfly to move without being pluged in, like if I was offroad on some rutted rough trails?
EGR has been unplugged since the truck was 300 miles old, I now have 19,5xx miles.
Are you running additive consistently? Have you tried increasing (doubling) treat rate?
The suspect refineries are all western Gulf plants, but no idea who they are. I'd imagine it's all Shell plants, making the end dest. the Williams pipeline which goes clear north to Canada. They won't be fined as (they say) it's a federally approved method to temporarilly increase production until we're caught up on production. This is all hearsay, mind you, but there's a definate reason people are having such drastic drops in mileage. This last tank I filled at a local station fed by the Sully Tank trucks (West coast tankers) instead of a big chain store and went right back up to 10.8 with 12,000lb. trailer. That's with a 300% add of FPPF total power on every fill (for 2 months now). Go figure...T
I should add that ynot had a sticky STINKY injector when he last visited. This prompted the heavy use of FPPF Total Power which last I heard had completely cured the issue. It was rolling blue-white smoke pretty hard at times...
Originally posted by kennedy:
Are you running additive consistently? Have you tried increasing (doubling) treat rate? I run 1.5x FPPF Total Power treat ratio in EVERY tank year round.
Sorry John. That should have been added to my post. Smokes a little at startup cold, clean in 15 or 20 seconds at 40 degrees. Runs hard after that with no issues. If I leave it out it ****s all over the place. Power Service and the other store brands don't do squat. Thanx Bud!!!!!!!...T
Jim Brzozowski
10-18-2005, 08:15
Buck, based on what your've provided, it sounds to me like a combination of exhaust restriction in getting the exhaust gasses out the end of the pipe and too much exhaust recirculation causing the engine to see hotter temp's while probaly not performing as well as it should. Does it seem down on power? Is it smoking more than usual? If it's what I said it should be down on power from not being able to breeth(can't put any more in than you can get out), but If its smoking more than usual I would suspect something not right with the fuel? You really got us all scratching our heads over this one? Sorry I can't be more help, but thats about all I can think of.
Originally posted by ynot:
Sorry John. That should have been added to my post. Smokes a little at startup cold, clean in 15 or 20 seconds at 40 degrees. Runs hard after that with no issues. If I leave it out it ****s all over the place. Power Service and the other store brands don't do squat. Thanx Bud!!!!!!!...T Do a compression check and I'd bet the offending cylinder is just a c-hair low...
Originally posted by SoTxPollock:
Buck, based on what your've provided, it sounds to me like a combination of exhaust restriction in getting the exhaust gasses out the end of the pipe and too much exhaust recirculation causing the engine to see hotter temp's while probaly not performing as well as it should. Does it seem down on power? Is it smoking more than usual? If it's what I said it should be down on power from not being able to breeth(can't put any more in than you can get out), but If its smoking more than usual I would suspect something not right with the fuel? You really got us all scratching our heads over this one? Sorry I can't be more help, but thats about all I can think of. It does feel kinda sluggish like it has more turbo lag. I added another 1.5x of Total power, we'll see what that does.
Originally posted by kennedy:
</font><blockquote>quote:</font><hr />Originally posted by ynot:
Sorry John. That should have been added to my post. Smokes a little at startup cold, clean in 15 or 20 seconds at 40 degrees. Runs hard after that with no issues. If I leave it out it ****s all over the place. Power Service and the other store brands don't do squat. Thanx Bud!!!!!!!...T Do a compression check and I'd bet the offending cylinder is just a c-hair low... </font>[/QUOTE]No need. It's coming out next month for pistons, rods, girdles etc...T
Well, I am finally starting to get somewhere. I added 1.5x more total power = 3x recommended treat ratio. I plugged the EGR back in for 1 day and unplugged it again.
The DIC has always been fairly accurate on my truck, generally running 8% low on it's figures. It has been indicating 14.2 up from its 9.7 mpg figures. I always hand caculate mpg for the hard numbers. I can't wait to fill'r up this time to see if mpg went up.
I have checked the trucks miles compared to my GPS and the truck is 8% lower due to the tire size. Oh, I did a couple boosted launches in an attempt to free something :confused: dunno if it did anything...... I did notice a bunch of soot covered Asian ladybeetles laying on the ground about a foot from the end of my tailpipe, which lead me to the boosted launches.
I got some spray that kills those bugs pretty quick. "Ortho Home Defence" a lot less of them flying around now ;)
ynot,
It still would be good to know. That one cylinder may have a slight tweak to a rod or a stuck ring. Good info to know what the compression was.
Buck,
We have a guy spray our buildings spring and fall. Takes care of the flies and beetles really well.
Sounds like fuel quality may have been the culprit if the additive picked it up. I really like the stuff!
BTW, I just laid a pr of 200'+ stripes off a nboosted launch with my LLY. Really didn't expect it to do so good, but it really FRIED the tires and left a cloud of blue without hardly any black... :cool:
Originally posted by kennedy:
BTW, I just laid a pr of 200'+ stripes off a nboosted launch with my LLY. Really didn't expect it to do so good, but it really FRIED the tires and left a cloud of blue without hardly any black... :cool: Somethin new or good pavement?
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