TimberJack Posted March 12, 2016 Share Posted March 12, 2016 I have a 2004 CH and just had Mack install a new VTG module, they said at idle the vane actuator lever should be in the down position. Well I noticed mine will be in the down position for awhile but then will go back up. But as soon as I tap the throttle it will go back in the down position. Is this normal? Vane Actuator Lever Quote Link to comment Share on other sites More sharing options...
wheeler73 Posted March 12, 2016 Share Posted March 12, 2016 You may have a defective vgt solenoid. It is mounted on the drivers side of the engine below the intake. You can follow the actuator air line to it. If it has oil coming out of the release port (rubber cap like a brake valve) it may be sticking inside due to the oil. It should be replaced if it has oil in it and the vgt coalescing filter changed as that filter is most often never changed. If it does not have a coalescing filter one needs to be added. When this is done the vgt should be re-calibrated. Also the vanes in the turbo could be sticking. Quote Link to comment Share on other sites More sharing options...
TimberJack Posted March 12, 2016 Author Share Posted March 12, 2016 (edited) Ok I will check it out. I noticed when the lever is down you can hear alittle air coming out of the release port on the VTG module. The filter at the bottom looks new. Edited March 12, 2016 by TimberJack Quote Link to comment Share on other sites More sharing options...
wheeler73 Posted March 13, 2016 Share Posted March 13, 2016 Sounds like the solenoid is bypassing. Make sure your system air pressure is not over 130 psi. Also the actuator will not start working till 90-100 psi of air pressure. Follow the air line to the safety valve on the treadle valve and make sure the safety valve is not leaking. Quote Link to comment Share on other sites More sharing options...
TimberJack Posted March 15, 2016 Author Share Posted March 15, 2016 I checked very thing out. Max air pressure is120 and no leaks. Quote Link to comment Share on other sites More sharing options...
wheeler73 Posted March 16, 2016 Share Posted March 16, 2016 The solenoid suppling the air to the actuator may be defective. Also you may have a boost pressure sensor reading erratic. Had one come into the shop today with sluggish acceleration and no codes with a new turbo and it has a defective eecu. I did not get to see the truck first hand to see if the vgt actuator was doing the same thing. Just went by what the other tech said and gave him a test module to try. So that is another possibility. Quote Link to comment Share on other sites More sharing options...
TimberJack Posted March 16, 2016 Author Share Posted March 16, 2016 Ok thanks for the help. Looks like it will be this weekends project! Quote Link to comment Share on other sites More sharing options...
wheeler73 Posted March 17, 2016 Share Posted March 17, 2016 Let us know what you find. Quote Link to comment Share on other sites More sharing options...
TimberJack Posted March 20, 2016 Author Share Posted March 20, 2016 Ok guys talked to Mack and they wanted me to bring it in so they could check it out. After 6 hours found nothing they told me it was normal but from what I've read on the service bulletin it's not but they act like I have no clue what I'm talking about. I told them it says the lever should alway be in the down position at idle. The truck runs great but sometimes when you stop at a red light and go to take off it has no boost/power until you get up around 4 or 5 gear. I've noticed while sitting at the red light the sound of the exhaust will change it seems to get louder and that's when it will do it. Any help would be nice I'm about to go crazy on this one. Thanks guys Quote Link to comment Share on other sites More sharing options...
wheeler73 Posted March 20, 2016 Share Posted March 20, 2016 Try a boost pressure sensor as it could be reading erratic. 1 Quote Link to comment Share on other sites More sharing options...
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