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+--- Thread: 09 prostar horrible Mpg (/showthread.php?tid=4575)
09 prostar horrible Mpg - earnies2 - 05-22-2019
I had really good milage after the mandate was done. Then I broke a exhaust valve the shop rebuilt the head new valves seats and guides. They also put a new turbo, injectors, and new rod and main bearings. The truck ran horrible after the repair. I ended up replacing all 4 actuators and one injector was leaking down , now the truck runs good but I have poor milage loaded I get 5.5 to 6.2 driving 62-65. I checked with Rawze after the work was done and he checked my program and said it was good that was a year ago I wonder if there are any updates since then. I am also wondering if I should bring it down from 565 to 525? Would changing the injectors help.... the milage is killing me. Thanks in advance
RE: 09 prostar horrible Mpg - Lonestar10 - 05-22-2019
with my cm871 if i was getting 5.5-6.2 ied be in hog heaven rolling in the dough and i run roughly the same speed.
how do you pop a valve but not pop a piston/liner/block?
rebuilding the head instead of new was probably the first mistake if you read most of the posts on here if the head comes off new goes on. rebuilt head means lost tolerances because somehow they had to get the new seats in and so far most remanned heads have failed very early in life.
i dont know where you run but lately in the midwest the wind has been atrocious 20-30mph almost every damn day for the last week or 2.
RE: 09 prostar horrible Mpg - earnies2 - 05-23-2019
Terminator? Broke a piece off an exhaust valve and it went out the exhaust and nailed the turbo.
The shop that did the work was a machine shop they said the casting was good so we rebuilt it I found out after it was done that everyone says replace with new so far it's been good.
I run mid west to east and mostly light....13 spd 355 rears not in a hurry easy on the pedal...
RE: 09 prostar horrible Mpg - flatbed94kid - 05-23-2019
Boost gauge, pyro, shifting, air pressure, idle time, cruise, aerodynamics, engine broke in yet after the engine work and how many miles since engine work?
Overinflated tires to 115 psi?
Sometimes thumping tire and still didn't know I had a flat until I put a air gauge on it.
RE: 09 prostar horrible Mpg - flatbed94kid - 05-23-2019
I also wonder why I hear of some guys claiming they get 10mpg or whatnot out of a dd15 or 8 mpg without much issues. Or out of a brand new truck they are getting super good mpgs.
I mean then again they may be reading the trucks mpg but how accurate is that thing?
RE: 09 prostar horrible Mpg - Waterloo - 05-23-2019
I'm wondering what the oil pressure is like? Having seen the work my dealership did and hearing your story brings back ugly memories. And I would bump the HP down, unless you are hauling 100,000 lb loads. And like Nick said, a pyro and boost gauge, and never lug the motor, keep the rpm's up. I bet they dry started the motor, that is what my gut tells me by your description of how it was running when you got it out of the shop. The mileage sounds about right though, I get 6 mpg all day long pulling a dry van with a mid roof, no fairing. 18 speed with 3:42 rears. I have a factory 600hp set to 485hp, Rawze did the tune.
RE: 09 prostar horrible Mpg - earnies2 - 05-23-2019
(05-23-2019 )TruckerNick Wrote: Boost gauge, pyro, shifting, air pressure, idle time, cruise, aerodynamics, engine broke in yet after the engine work and how many miles since engine work?I have a pyro it runs 7-8 on a hill never over 850 my boost I watch constantly and try to keep it under 10 going down the road it will give me 40 psi on a good pull. I have a shimmed pump and I get 45-47 lbs oil at 1500 my oil temp runs 215 running on flatland and I can go to 235-240 on a hill. I do most shifts at 1600 and cruise at 1450-1500. I have verry little idle time APU. I am in a prostar with a high sleeper and full fairings. It has been a year since the engine work and 100k. I have cat eyes on trailer and drives I run 120 in all my tires. I recently changed my CAC and all boots on the hot side, new air filter, crankcase filter, and I had to remove the ifsm to do a primer pump because the heads of one bolt was stripped out.whal it was out I was amazed at how clean the intake was. I recently had a oil sample done and it was verry clean I have no blow by and I loose mabe 1 gallon of oil in 15k.
Overinflated tires to 115 psi?
Sometimes thumping tire and still didn't know I had a flat until I put a air gauge on it.
I don't know what I'm missing because I was getting a constant 7.5+ before and if anything my driving habits have improved to try and get my milage up.....
RE: 09 prostar horrible Mpg - Rawze - 05-23-2019
(05-23-2019 )earnies2 Wrote:(05-23-2019 )TruckerNick Wrote: Boost gauge, pyro, shifting, air pressure, idle time, cruise, aerodynamics, engine broke in yet after the engine work and how many miles since engine work?I have a pyro it runs 7-8 on a hill never over 850 my boost I watch constantly and try to keep it under 10 going down the road it will give me 40 psi on a good pull. I have a shimmed pump and I get 45-47 lbs oil at 1500 my oil temp runs 215 running on flatland and I can go to 235-240 on a hill. I do most shifts at 1600 and cruise at 1450-1500. I have verry little idle time APU. I am in a prostar with a high sleeper and full fairings. It has been a year since the engine work and 100k. I have cat eyes on trailer and drives I run 120 in all my tires. I recently changed my CAC and all boots on the hot side, new air filter, crankcase filter, and I had to remove the ifsm to do a primer pump because the heads of one bolt was stripped out.whal it was out I was amazed at how clean the intake was. I recently had a oil sample done and it was verry clean I have no blow by and I loose mabe 1 gallon of oil in 15k.
Overinflated tires to 115 psi?
Sometimes thumping tire and still didn't know I had a flat until I put a air gauge on it.
I don't know what I'm missing because I was getting a constant 7.5+ before and if anything my driving habits have improved to try and get my milage up.....
has the overhead valves been adjusted since the inframe? - Maybe check em again?
Maybe wedge the engine to ensure a cam did not slip?
if you can get 40+ psi then the turbo is adjusted up a bit too high. That can also make fuel mileage fall off a bit.
those oil temps in a hard pull sound a tad high as well.
RE: 09 prostar horrible Mpg - earnies2 - 05-23-2019
(05-23-2019 )Waterloo Wrote: I'm wondering what the oil pressure is like? Having seen the work my dealership did and hearing your story brings back ugly memories. And I would bump the HP down, unless you are hauling 100,000 lb loads. And like Nick said, a pyro and boost gauge, and never lug the motor, keep the rpm's up. I bet they dry started the motor, that is what my gut tells me by your description of how it was running when you got it out of the shop. The mileage sounds about right though, I get 6 mpg all day long pulling a dry van with a mid roof, no fairing. 18 speed with 3:42 rears. I have a factory 600hp set to 485hp, Rawze did the tune.My oil pressure is 20 idle and 45-47 going down the road. What should I put the hp at 475,500, or 525 I have a pyro and boost gauge and watch them constantly. I run down the road at 1450 to 1500 rpm I pull most hills at 1400 to 1700 rpm. Since the work was done I did change all 4 actuators and 1 injector I don't. run heavy I always try to run as light as possible usually under 30k on the deck. Do you think a new set of injectors would help? I'm only suggesting this because I have already had a problem with 1.