Boosting for no reason

[Lostfarmboy]

Well I got the leaks fixed in the intake track and the problem is not solved so back to the drawing board.

[Jose9640]

(11-27-2018 )marek4792 Wrote:  Are your sensors all new? IMAP, Exhaust Pressure, EGR Differential pressure sensors? I asked because I had a CM870 with the air powered VGT and it would build 35+lb's of boost with my foot barely on the pedal and then the next time would be okay. While the boost would spike under load, the engine would choke itself out and slow you down blowing a big cloud of black smoke behind you in the process. If you hold the pedal too long the turbo will "chuff" violently until you back off the pedal. Granted a CM870 is a different animal then the 871, but it definitely is turbo/egr related especially if it does it intermittently.

What was your issue in this case? My cm2250 is doing the exact same thing. New imap, exhaust pressure sensor. Only code that comes up is 2554.

[Lostfarmboy]

I didn't get any codes. A new head and valve camshaft didn't fix it but removing the mandate took care of it.

[marek4792]

(04-17-2019 )Jose9640 Wrote:  

(11-27-2018 )marek4792 Wrote:  Are your sensors all new? IMAP, Exhaust Pressure, EGR Differential pressure sensors? I asked because I had a CM870 with the air powered VGT and it would build 35+lb's of boost with my foot barely on the pedal and then the next time would be okay. While the boost would spike under load, the engine would choke itself out and slow you down blowing a big cloud of black smoke behind you in the process. If you hold the pedal too long the turbo will "chuff" violently until you back off the pedal. Granted a CM870 is a different animal then the 871, but it definitely is turbo/egr related especially if it does it intermittently.

What was your issue in this case? My cm2250 is doing the exact same thing. New imap, exhaust pressure sensor. Only code that comes up is 2554.

Unfortunately I was never able to figure out what it was definitively as my truck was wrecked after getting the turbo rebuilt at YTS in GA and a 3 week stay at Rawze's, we think the vg-vane movement was restricted due to the vg-ring being a fixed design and not the floating type, which would have required the turbo being "reclocked" to allow for free movement of the vg-vanes, or maybe in your case carbon packing or the actuator hanging up? Rawze goes into detail here about what mine was doing while I was there.. http://rawze.com/forums/showthread.php?tid=3673

[Jose9640]

(04-17-2019 )Lostfarmboy Wrote:  I didn't get any codes. A new head and valve camshaft didn't fix it but removing the mandate took care of it.

This truck is de-Mandated. I had a VGT not responding code. I cleared all of them after I changed the exhaust pressure sensor. Now the vgt codes aren’t coming up but the exhaust pressure code is.