Code 2632-000 after Tune
 

Got a Stage 1 tune on one of my CDI's. Had a good experience so got it done on the other. After the tune I experienced "kangarooing" upon hard acceleration....a judder or oscillating hesitancy. The code that was thrown and keeps coming back is 2632-008 "Check system charge pressure." What I have not done yet is go back to the stock tune and see if it still throws the same code.

Either way, what problems cause that code to be thrown? I think the turbo actuator is a possibility from what I read.

The tuner won't be able to provide any definitive guidance until I am able to record live data of boost and rail pressure.

Thanks.

Make sure you don't have any weak areas on the charge piping/hose from discharge of turbo to intake manifold. Also make sure inter cooler does not have a weak spot that could leak during boost.

Agreed if you have a pressure loss from turbo thru intercooler to intake manifold it will throw CEL and limp mode, one of my 642s had this (operator error during reassembly) and it was worse than a 240D.

The charge pressure is too high maybe your veins are binding.

Yep that’s a possibility too. The VNT vanes can get carboned up.

The VNT works backwards of what you might think.

The vanes allow a path around the exhaust impeller when open. This reduces the flow to the impeller, so the rotor turns slower, thus reducing the intake pressure.

If the vanes stick shut, then it can’t modulate the intake pressure, and the computer throws the flag.

I had that problem too and it did manifest itself as a jerky acceleration from a red light.

http://www.peachparts.com/shopforum/diesel-discussion/403465-om642-vnt-turbo-actuator-issues.html

On a 642 but I think most of the systems are similar to the 648.

But I will say the jammed VNT did flag a stuck actuator because there is feedback to the computer when the servo tries to move the vanes and can’t.

Easy test, unclip the arm from the servo and try to move the vanes and see if they are sticky. Don’t try this with the servo hooked up or it will damage the gears.

Or if you have a Xentry go into engine control, guided tests, and do the actuator test and watch it go back and forth.

The Foxwell scanner also preforms that test and a live spool up test which will likely identify an issue.

I will add that the car drives beautifully otherwise....the kangarooing is only noticeable at full throttle.

Also, I don't know for a fact that the tune triggered the throwing of the code. It could have been there for who knows how long without any adverse effect on performance.

EDIT: I deleted the code, drove it hard for a while, experienced the same kangarooing upon hard acceleration, but the code did not come back. Hmmm....

To close the loop on this....One of the things the tuner noted originally was that there was some sort of checksum error in the stock file, an error which he thought he had corrected in the tune. But, when my issue persisted, he decided to create the file using a different program, one that he doesn't ordinarily use. I loaded the file this morning and, VOILA!, no more kangarooing. He's still a bit mystified as to exactly what the problem was with the first file. But glad he was able to solve the problem without my having to take all sorts of live readings.

I have experienced the same thing you did.
Curious who your tuner is.
It is almost like you were reading my mails.
My stage 1 works great now but i decided if some is good, more must be better.
Went to stage 2 and the pulsing is back. Same code as you.
Tuner is at a loss as am I. My guess is there is a combination of data that causes the ecu to rapidly fluctuate outputs and the different file without the checksum was a work around.

I'll send you a PM.

Shertex
Hello new member here... any possibilty you could send me that same IM mentioned above?