Accerlation sputter loud noise ARD HEAD?

Discussion in 'Trucks [ Eighteen Wheelers ]' started by tsass, Mar 17, 2010.

  1. tsass

    tsass Bobtail Member

    I have an early model 2008 C-15, serial number SDP. Upon moderate to heavy acceleration or shifting through the gears, the engine is momentarily extremely loud, sputtery, sluggish as though the exhaust or a baffle is wide open. Then within a second, it's like a baffle slams shut and is quiet like it should be then all sorts of power comes out of nowhere. It may do this a couple times before my next shift. I can reproduce it by slamming on the accelerator or just lightly touching it. It seems to occur only when the engine is warm. It seems to be nearly every time, though the last few miles tonight it would not do it. I was unable to reproduce it until just before I stopped driving. Then it began the same thing over again. Could this be a bad CGI Valve? ARD Head? Perhaps a leaking air to air boot? There has to be moderate to severe acceleration for it to occur. Driving up and down the hills bobtail was questionable but it was mostly fine until I'd hit the accelerator after coasting.

    Secondly, while sitting stationary, the idle is flawless. It's real smooth! But while driving at any speed in any gear, the idle surges but ever so slightly where it makes an audible difference in sound of the engine and at the same time, so does the boost gauge surge. Perhaps 5 psi it will bounce up and down. Does any of this sound familiar to anyone? Could it be a bad CGI valve? Turbo leak? Exhaust leak? Air to air? A trip to Cat? I just had the pipe from the block to the CGI cooler replaced as it had a cold leak. If the pipe was bad, so too could everything else down the line I suppose? Also fixed an exhaust manifold leak. These symptoms existed prior to these repairs.

    Would the ARD head have anything to do with this? It has been serviced several times but I am unclear as to how it would affect or relate to my current symptoms. It just seems like the ECM is over/under compensating CGI as one has suggested regarding the surging idle. Aside from these two issue, everything else seems to work fine. Fuel mileage was 9 mpg bobtail running 75mph, 1500 rpms.

    Any suggestions, much appreciated
     
    Last edited: Mar 17, 2010
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  3. Dutch

    Dutch Light Load Member

    194
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    Nov 21, 2009
    Commiefornia
    0
    ah i wish i could look at the engine and help you out that way. its hard to t/s these cats over the net. an air syst. verification test should be ran, and datalog during a drive or on the dyno and see what boost cgi flow and fuel rate are doing
     
  4. 1989 Pete

    1989 Pete "Pine Tree Eater"

    Sounds like a call to the Pitts boys give Pete a call he should be able to help ya
     
  5. tsass

    tsass Bobtail Member

    Thanks. Need more info, who are they and how do I contact?
     
  6. lowbudget

    lowbudget Medium Load Member

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    Apr 12, 2008
    Bismarck, ND
    0
    I think he's referring to Pittsburg Power?
     
  7. tsass

    tsass Bobtail Member

    Thanks. Not sure what the Pitts box will do for my issues. Problem is, I tried to reproduce for the local CAT shop today with laptop in hand on a test drive.... It made the loud momentary noise for them. He said it is normal. The pulsing idle never showed up. It ran almost flawlessly. No pulsing idle whatsoever... Just ran perfectly. It has plenty of power, so I'm not sure the Pitts Box is related or a cure all for my truck. Any other time, it will run as I have described... Naturally, when I need it to run as it has as a demo for the mechanic, it won't reproduce itself.:biggrin_25510:
     
  8. Polarbear

    Polarbear Light Load Member

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    Nov 30, 2007
    USA
    0
    You have to watch if you are using too much antifreeze. Sometimes is leaks into the exhaust and that indicates a bad EGR valve.
     
  9. tsass

    tsass Bobtail Member

    I have CGI, not EGR. Too, the local CAT dealer says I do not have a CGI Valve. Strange considering my ESC Warranty says the CGI Valve I don't have is covered under the CAT warranty.
     
  10. Dutch

    Dutch Light Load Member

    194
    58
    Nov 21, 2009
    Commiefornia
    0
    no cgi valve? I have yet to see one without one lol. give me an complete s/n. Idk just thinking a sticking vva assembly? They pull any cgi mass flow codes? and run a asvt?
    Cats having us go thru another training program. So im anticipating another update is in the works just like when they came out with the 07 confidence program we had a few years back
     
  11. tsass

    tsass Bobtail Member

    Thanks for the reply. Engine serial is SDP5088. I don't know what a "sticking vva assembly" or an "asvt". Whatever is happening, it's almost 99% only when the engine and outside temps are warm. The pulsing idle seems to act up when cold or warm. Although, I was unable to reproduce it when I took the CAT tech with me. He had his laptop hooked up and not one anomaly occurred. It's truly frustrating that it would not act up at all while he was in the truck. What I can say is, something is sticking open or shut then releasing. During the test drive with the Cat Tech, the outside temps were in the lower 50's. Engine temp was around 180. It's odd because for several hundred miles of nonstop driving, it would not act up. Then, after would I stop to rest for just a few minutes, it would act up again. There were several codes in the system, all of which occurred at the same time when my batteries were dead and replaced. I believe the codes have been erased. There are no warnings on the driver display.

    Please let me know your thoughts. What is a VVA Assembly and ASVT and what do they do?

    Thanks!
     
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