ISX400 Intermittent and varying boost pressure

[Vman]

I got to think others have had this problem and will be reading posts about low or inconsistent boost. In the meantime I will tell some details of what the problem is to which I seek what I should be looking at. For about 10 years I have driven a 2010 T2000 ISX400ST. The whole time it has been inconsistent boost pressure from one mountain to the next and even from gear to gear on the same hill. I have seen it anywhere from 15 to 35+ psi on any given day. Recently while in the rolling hills approaching the northbound scale at Anderson CA. I felt the power drop off to almost nothing, I saw the boost drop before my eyes from 30 down past 20, 15, 10, 5,.... No smoke in the mirrors, no check engine light, a couple of downshifts and it WAVERED it's way back up around 25psi. I stopped to have it checked in Redding before starting up the Siskiyou's where they told me the turbo was worn out. 2 weeks, a rental truck, plus $7500 later I hooked back onto the trailer and started north with a reman turbo but still my old actuator. On the very first hill climb up to Shasta Lake I didn't think I was going to make it. Below 20psi and down shifting as fast as I could I crawled over the top. The next hill a little better at 25 or so. Most of the 6%ers it was 20 to 28 showing on the gauge all the way through Oregon and Washington up as far as JBLM where it miraculously pumped up to 35+ at full throttle and ran the last 15 miles or so like I think it should have been for the whole 10 years I have driven this truck. I think the turbo never was / is not now the real problem. Cummins did a $22,500 inframe a few years back, but that had no effect on this issue. What other things are involved with determining how much boost the turbo makes? Sensors? Circuits? Advice? Thank you.

[Rawze]

you can guess at it until you are blue in the face.. and it will get you no-where.

Use the Insite software to monitor the fuel control state and other things to see why it might be holding back boost/power. - Unless you do this, you will never know what is going on. There are more than 12+ different engine operating modes depending on altitude, the temperature of the DPF/SCR, etc.. and all other factors. -== There is no way in h#ells creation anyone can guess at it. You need to get the software and an adapter and drive it / monitor things live while it is acting up.. and see exactly what that engine computer is telling to to do. -== NO REPAIR SHOP is going to do this.. so if you don't have an adapter (cummins inline 6 kit) and Insite software.. that is your first investment... About $300 bucks or so is all it takes to get that stuffs if u look in the right places on the internet.


Also, if your taking to to the OEM collection of complete morons.. you will waste moneys endlessly on it with no result.. they are not trained to actually solve any problems but to only get the check engine lights to go out or sell you expensive components like turbo, etc. with no justification other than emptying your wallet.


Also. if the truck is de-mandated (deleted) assume the program is bad and copy it out, e-mail it to me for a proper review.

If it is NOT deleted.. and all the emissions are still intact .. then a thorough EGR tune-up would likely do it a world of good...
ref: http://rawze.com/forums/showthread.php?tid=7&pid=9#pid9

[Vman]

All OE. Nothing deleted. Will check your link. Thank you

[Vman]

Thanks Rawze, I watched the egr tune up vids. Looks like I have some cleaning to do

[Bengy88]

If you have insite and a hotspot i can remote in and check a few things while you take the truck on a short drive and most likely tell you whats going on... But rawze is 100% correct. If your egr hasnt properly been serviced it will cause crazy issues and definately needs servicing ASAP. Under boost just being one of the issues you will see from a poor egr system.

[Vman]

Ok, did the whole left side egr clean out. Found the imap completely clogged with carbon/soot. Got a new one from KW for $86. Did the egr valve and all. Gonna follow through with the right side stuff as soon as I can. Whole lot cheaper than the $7500 turbocharger that I didn’t need. Thank you Rawze for the great videos. I love to learn from people that know.

[Vman]

(10-20-2022 )Bengy88 Wrote:  If you have insite and a hotspot i can remote in and check a few things while you take the truck on a short drive and most likely tell you whats going on... But rawze is 100% correct. If your egr hasnt properly been serviced it will cause crazy issues and definately needs servicing ASAP. Under boost just being one of the issues you will see from a poor egr system.

Thank you 88. I saw Cummins in-line 6 kit with Insite on eBay for about $250. Is that what I need?

[Bengy88]

Most of the diagnostic connectors on ebay are chinese clones.... Not saying they wont work just do a little research before you buy it and make sure its a legit seller. Send me a pm and ill help you out with finding everything you need