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+--- Thread: 871 Horrible fuel milage (/showthread.php?tid=1525)
871 Horrible fuel milage - Rockycoon75 - 03-01-2017
I have a 11 pete with a 485/1850 871 18 spd 3.55 rears getting horrible milage. I bought it about a month ago. It has 100k on a dealership overhaul. I did the egr tune up when I got it. New imap delta p and exhaust pressure sensor. Doser injector was previously replaced and was pretty clean. Truck isn't smoking at all and water temp is running between 180-190 oil temp 210-220. No codes no lights.
Over the last 2300 miles I'm getting 4.8. Half of the miles were empty
Doesn't seem to matter if I run 60 or 70 still sucking fuel. Power seems to be good.motors feels to run best smoothest between 1300-1650 under or over its feels a little rough almost like a miss. Usually holds 32 on manifold pressure. I have seen it pull 40+ several times and at times only pull 30. Not sure where to begin with it[/size]
RE: 871 Horrible fuel milage - Brock - 03-01-2017
(03-01-2017 )Rockycoon75 Wrote: I have a 11 pete with a 485/1850 871 18 spd 3.55 rears getting horrible milage. I bought it about a month ago. It has 100k on a dealership overhaul. I did the egr tune up when I got it. New imap delta p and exhaust pressure sensor. Doser injector was previously replaced and was pretty clean. Truck isn't smoking at all and water temp is running between 180-190 oil temp 210-220. No codes no lights.
Over the last 2300 miles I'm getting 4.8. Half of the miles were empty
Doesn't seem to matter if I run 60 or 70 still sucking fuel. Power seems to be good.motors feels to run best smoothest between 1300-1650 under or over its feels a little rough almost like a miss. Usually holds 32 on manifold pressure. I have seen it pull 40+ several times and at times only pull 30. Not sure where to begin with it[/size]
What kind of weight are you hauling when your loaded? What area are you running?
RE: 871 Horrible fuel milage - Mr Hagg - 03-01-2017
Have you did a charge air leak test? Also over head maynot be set right. Along with cam timing and a few other things. How does truck pull? May do injector bubble test too..
RE: 871 Horrible fuel milage - Rockycoon75 - 03-01-2017
Pulls good between 13-1650 . Checked all the cache boots and connections and couldn't find a leak. Will have to check cooler when I get home. Overhead should be done this weekend.
RE: 871 Horrible fuel milage - Nilao - 03-01-2017
If it's dropping boost I'd suspect a silent derate. Also 40 on the boost is too high.
RE: 871 Horrible fuel milage - Rockycoon75 - 03-01-2017
I've been trying to watch the boost and back out of it when it goes up that high. Just never know when it's going to do it. May be normal 32-33 for several pulls then bam 40+
RE: 871 Horrible fuel milage - Brock - 03-01-2017
My boost is always just shy of 40 on hard pulls