12.7 no turbo pressure

Discussion in 'Trucks [ Eighteen Wheelers ]' started by Trcknwolf, Jan 20, 2022.

  1. Trcknwolf

    Trcknwolf Light Load Member

    52
    21
    Nov 24, 2010
    Bellevue, NE
    0
    I've got a 12.7 Detroit in a 1999 Pete 379. Truck fired right up Monday morning & ideled up like normal. Warmed her up for about 20 minutes with no issue. Hooked up trailer. Engine was running & accelerating like it should. Got out on I-29 heading South. Engine accelerated normally. I set the cruise @ 72 mph. Engine was operating great. 50 miles down the road, cruise still set @ 72, turbo pulling 5-6 lbs boost, engine & turbo "tone" both changed. Truck starts to decelerate while still on cruise. Usual turbo "whistle" is gone. The foot feed made the engine respond, but NO boost whatsoever. Took next off-ramp. Stopped truck, set brakes. Engine ideled normal. NO CEL or SEL! Foot feed made engine rev as it should, . Shut engine off. Waited 5 minites, restarted fine. Foot feed still made engine rev normally. Opened hood & looked over everything. Nothing electrical broken or disconnected I can see). No signs of oil anywhere. CAC (Duralite) is less than a year old. New orange silicone hoses & clamps same time. No air leaks I can hear. All clamps tight, hoses fine. While engine was running, I unplugged both the intake manifold sensors. Each would trigger a CEL when unplugged. CEL would go off when replugged. There was no "bang" like a hose blew or anything like that. Engine sounds normal both @ idle & thru the entire rpm range up to the limiter. Removed intake air hose & impeller spins freely with the expected endplay. No side-to-side movement. Engine has 350ish thousand miles on complete overhaul. Never had any problems. Installed a Full Tilt exhaust manifold & stage 1 turbo same time. No tune. Engine has ran & performed great on overhaul. Fuel economy has been good, engine pulls fine. Operating EG temps have always been in normal ranges. Engine IS due for service. Had truck towed to usual mechanic. He hasn't got to her yet. ANY ideas boys??
     
  2. Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  3. Old Man

    Old Man Road Train Member

    4,443
    12,501
    Apr 3, 2009
    Oklahoma City, OK
    0
    Fuel filters? You have a fuel pressure gauge?
     
    little cat 500 Thanks this.
  4. kranky1

    kranky1 Road Train Member

    1,210
    3,855
    Sep 16, 2015
    Ontario, Canada
    0
     
  5. Big Road Skateboard

    Big Road Skateboard Road Train Member

    1,299
    4,414
    May 2, 2021
    0
    Do you have a lot of black smoke? Just because the boost sensor makes a ck engine light come on, does not mean it is reading correctly.
     
  6. DDguy

    DDguy Light Load Member

    62
    26
    Apr 21, 2020
    Ont. Canada
    0
    I am suspecting maybe a Possible derate hooking up DDDL to it and taking it for a spin might determine ? check if theres any torque limiting taking place Check how much Pulse width its making when you try to accelerate If this would all look normal you might have a Timing Issue ? or a Major boost leak that just didnt cause a Bang ?
     
  7. Trcknwolf

    Trcknwolf Light Load Member

    52
    21
    Nov 24, 2010
    Bellevue, NE
    0
     
  8. Trcknwolf

    Trcknwolf Light Load Member

    52
    21
    Nov 24, 2010
    Bellevue, NE
    0
    Fuel filters are fine. Truck has a fuel pressure gauge. It was reading normal pressure going down the road at the time.
     
  9. Trcknwolf

    Trcknwolf Light Load Member

    52
    21
    Nov 24, 2010
    Bellevue, NE
    0
    Old Man: the truck does have a fp gauge & was at normal operating pressure. MLC Adventures: the only black smoke she makes is when I shift, which is very minimal. I blame the ####ty fuel we are offered these days. DDguy: No derate. Only thing stored in the ECM memory is from me unplugging the boost & manifold temp sensors. Otherwise, the ECM reads completely normal. kranky1: YOU, sir, are on to something there!!
    UPDATES: turbo checked out fine. NO boost leaks anywhere in the system. Truck was due for service anyhow. Fuel filters checked out fine. Replaced both the boost & manifold temp sensors & VIOLA!, truck is back in usual running condition. Shaking my head but, WHATEVER...
     
  10. DDguy

    DDguy Light Load Member

    62
    26
    Apr 21, 2020
    Ont. Canada
    0
    Nice that people can discuss problems here are you suggesting that possibly a pc of crap or soot plugged boost Pressure sensor and with that the ECM just didnt know that and therefore there was no code ? Or do you think internally the boost sensor quit reading pressure but it never did affect the electrical side of the sensor ?
    This is totaly a new one for me as well but we see all kinda of funny crap
     
  • Truckers Report Jobs

    Trucking Jobs in 30 seconds

    Every month 400 people find a job with the help of TruckersReport.

  • Draft saved Draft deleted