griffvision Posted January 7, 2023 Share Posted January 7, 2023 hi all, Long time lurker of posts, thank you all for the vast knowledge on here, I've used info many times, it is my First time posting; So I have a 2006 CXN613 vision , with AC460 CEGR engine. I have been having intermittent low power/ low boost problems with the truck, sometimes truck pulls great and makes 30+ psi boost, others can't get the truck to hold 5 psi. Seems to happen more frequently after about 1hr of use. I've had the truck to several garages, all to no avail. Some background on what has been done: I have checked for loose wires at eecu connectors (as this had been a problem causing truck to shut down while driving in the past) I have replaced and calibrated fuel pedal, all good. I have checked VTG operation visually and while driving with a GoPro, all seems good. I have disconnected and pressure tested charge air cooler and piping, no leaks. Fresh fuel filters, air filter, no fuel restrictions No current active codes (getting an occasional 6-4 flash code, but not corresponding with low power occurrence. I have replaced boost pressure relief valve, thought this was my issue as I tested it and it was weak, opening at 3-4psi; when I replaced valve, after first startup the truck sort of coughed and ran rough for a second putting out blue smoke, test drove the truck bobtail, it pulled like a race car (maxing out boost gauge I installed) , I was excited thought I had issue resolved. Truck went to work the next day, ran great for about an hour loaded then lost power. No codes present. Anyone have any suggestions on where I should look next. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted January 7, 2023 Share Posted January 7, 2023 have you replaced the air filter for the VGT acuator? Welcome to the Dog House.. Jojo Quote Link to comment Share on other sites More sharing options...
griffvision Posted January 7, 2023 Author Share Posted January 7, 2023 Thanks I have not, will try that tomorrow. thats the small one on drivers side of engine by side of frame rail? I did disconnect stainless air line going to actuator and there seemed to be lots of air, didn't pressure check it or anything though. Put a small bit of shop air to actuator and it moved rod up and down easily. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted January 7, 2023 Share Posted January 7, 2023 Thats the filter.. A lot of folks dont change it anually, as it should be.. The module that it filters the air for, is expensive, I suggest you put that filter on your P.M. schedule.. I should know the part number, but I dont... sorry.. If you can read the filter number, call NAPA and get a cross reference.. Lets keep it simple from the start.. No need to load a parts cannon with hi dollar parts, only to find it was a filter or broken wire,,, Jojo 1 1 Quote Link to comment Share on other sites More sharing options...
fjh Posted January 8, 2023 Share Posted January 8, 2023 You did good replacing that bypass valve they were made to start reliving around 20 psi it sounds to me that ! That new valve stuck for the first bit! I did alot of messing about with these when the engine first appeared on the seen ! I corked that bypass off completely on one truck ! The Vgt will generate WAY MORE air than that engine needs regardless of fuel ! It will pound the boost gauge to the MAX on a regular basis! The valve is meant to protect the turbo from Over Spooling and God Knows these turbos had a bunch of issues in the beginning! That said The EGR valve stuck open is another thing that could have been happening here ! Don't know give the stuff Joey has presented A try ! Keep us posted! 2 Quote Link to comment Share on other sites More sharing options...
griffvision Posted January 9, 2023 Author Share Posted January 9, 2023 thanks Fjh, when diagnosing I actually put a 1" plug in there where the boost relief valve goes and the truck ran great, pulled great and pounded boost gauge every time, this is why I thought I had the problem corrected..... no doubt I did have a worn out boost pressure relief valve but thats obviously not my only problem. In thinking of it; it was when I installed the plug on first start up the truck coughed when revved at idle (almost sounded like Jake on) and put out blue smoke out the stack and back through the tube that connects to bpr valve, could this be an indication of stuck egr or something else ? truck has not smoked noticeably when experiencing low power issues, nor coughed, just gradually dies out. I have the small air filter on order to arrive tomorrow that joey has mentioned above, we will see what that does too 1 Quote Link to comment Share on other sites More sharing options...
fjh Posted January 9, 2023 Share Posted January 9, 2023 So check your tank vent make sure the fuel tank is getting vented! Make sure you listen for a sucking sound when you remove the lid if you hear a woosssh the vent is plugged! Quote Link to comment Share on other sites More sharing options...
fjh Posted January 9, 2023 Share Posted January 9, 2023 Griff if you want to try something unless they changed the design I was able to tighten the spring in the boost dump valve you may want to pop it back off and see if that is still doable!? Quote Link to comment Share on other sites More sharing options...
griffvision Posted January 17, 2023 Author Share Posted January 17, 2023 hey guys, update: I have changed the small air filter for actuator like joey mentioned, I have also replaced boost pressure sensor. still no change. checked tank vents also, all good. I am getting an active 6-4 code all the time, truck works fine sometimes and pulls great, seems like after it works for about an hour it loses power, making little boost. Any suggestions ? would this 6-4 code be any guidance Quote Link to comment Share on other sites More sharing options...
fjh Posted January 17, 2023 Share Posted January 17, 2023 14 hours ago, griffvision said: hey guys, update: I have changed the small air filter for actuator like joey mentioned, I have also replaced boost pressure sensor. still no change. checked tank vents also, all good. I am getting an active 6-4 code all the time, truck works fine sometimes and pulls great, seems like after it works for about an hour it loses power, making little boost. Any suggestions ? would this 6-4 code be any guidance Bro ! Check the ECU plugs for coolant push or oil push! un plug them and look for signs of this! 1 Quote Link to comment Share on other sites More sharing options...
Vmac3 Posted January 17, 2023 Share Posted January 17, 2023 That 6-4 code is a J1939 code (communication error). Check what fjh suggested first, this was a real common issue. V Quote Link to comment Share on other sites More sharing options...
Mackpro Posted January 17, 2023 Share Posted January 17, 2023 Do you have any Qualcomm or data logger plugged into the 9 pin Diagnostic connector?? 1 Quote Link to comment Share on other sites More sharing options...
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