CAT C15 ACERT 475hp MXS - low boost

Discussion in 'Trucks [ Eighteen Wheelers ]' started by mile-high, Aug 22, 2009.

  1. mile-high

    mile-high Bobtail Member

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    Aug 22, 2009
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    Am checking these out. Will let you know what I discover.
     
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  3. PaulE

    PaulE Medium Load Member

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    Jan 15, 2009
    Verona Wi
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    yes, replaced both harnesses and have kept perf and mpg gains to date. have found the oil leaking into plugs a very common problem for the C 15( not just Acerts ) I now check inj plugs regular. they are still dry.good luck..

    Anyone put a site glass on between primary/secondary fuel filters? I realize with a Par dyno this should have been done but a friend had a NXS at Cat for low power and Cat said everythings within spec pay 1200.00. well they missed a cracked primary head that caused the low power. found by his own mech in 5 min.
     
    Last edited: Aug 24, 2009
    mile-high Thanks this.
  4. 05chopper

    05chopper Light Load Member

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    Dec 25, 2008
    USA
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    Replaced harness gained boost OK. Replacing wires without check engine light Hummm:biggrin_25523:
     
  5. PaulE

    PaulE Medium Load Member

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    Jan 15, 2009
    Verona Wi
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    In my case i had intermitent IVA codes and a rare miss but always ran rough and low boost. stumbled on the oil in inj plugs taking PP box off before taking into Cat. OP has not said if he has codes up. make sense now?
     
  6. 05chopper

    05chopper Light Load Member

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    Dec 25, 2008
    USA
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    What doesn't is mile high didn't get what he paid for when he was at cat with the par. I will say it again if all looks good on a par dyno except for the missing data then we all can do is assume. Yep get it now do you:biggrin_25523:
     
  7. 07-379Pete

    07-379Pete Crusty Commando-Pete

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    Oct 3, 2008
    Campbellsville, Ky
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    What?:biggrin_25521:
     
  8. mile-high

    mile-high Bobtail Member

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    Aug 22, 2009
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    Update:
    Looked for air leaks on cylinder head on intake side, couldn't find anything.
    I never got any codes while this boost problem has existed, so to see if codes would come up at all, disconnected manifold air temp sensor, boost sensor, IVA solenoid and the water diffuser and codes came up for all and went away as soon as I plugged them back in.
    Cleaned the electrical connections to IVA and injector harness as mentioned previously. Got improvement in boost.
    Replaced primary fuel filter with a 256-8753 (CAT refers to these as water separators) (had 175-2929 on it before--didn't know there were different filters--it's had 175's on since I got it.). Don't know impact on boost yet because as a bobtail it hit 75 mph very quickly and never needed more than 35 lbs of boost to do it which it wouldn't do before. Tomorrow will take my stacked up trailer that weighs 48,000 empty and see how it reacts with a load.
    Also looked for cracks in the housing, didn't find any.
    Ordered spring kit 339-4983, will pick up tomorrow and install.
    They didn't use a site glass when they ran the PAR (used their own transfer pump to my transfer pump). Am going to disconnect the return line on one side, put in a fitting with clear plastic tubing on it and run it to the tank so that maybe I'll be able to see if there's air in the fuel line.
    Thanks for all suggestions. It's been a big help. Any more will be welcome and appreciated.
     
  9. PaulE

    PaulE Medium Load Member

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    Jan 15, 2009
    Verona Wi
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    Mile High, glad your making a little progress. Cat filter 256-8753 is part of upgrade they had a few years ago it requires a new filter head ( 120 gph ) to work correctly. 175-2949 has same thread size but was used with a 90 gph head. I have # for head but without knowing fitting size dont know what # to give you. all dealers know about this so shouldnt be a problem to get right head. Cat was solving a fuel restriction issue. I have filter #s that provide a further improvment over 256-8753 and fit on same head.i can give info after you get it fixed if your interested. good luck
     
    mile-high Thanks this.
  10. mile-high

    mile-high Bobtail Member

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    Aug 22, 2009
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    Will measure fitting size and go get 120 gph filter head and install today. Would be interested in info on filter that provides further improvement.
    Was going to get spring kit today and install but am thinking I may just shim the old spring. (I have old style pump with 5/8 hex head plug.)
     
  11. mile-high

    mile-high Bobtail Member

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    Aug 22, 2009
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    Does anyone have any ideas about why no codes have ever showed up? Didn't get any when problem started, during problem or during DYNO. Tested sensors yesterday and they appear to be working.
     
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