m157 boost issues??? - MBWorld.org Forums

Mar 25, 2020 | 02:45 PM

jclaus98

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Member

Joined: Aug 2013

Posts: 131

Likes: 4

From: Reno, NV

2012 ML63 AMG, 2015 RAM 2500, 1968 Charger

m157 boost issues???

Gentlemen, looking for some assistance from this group since I wasn't getting much help in the other forum. I have a bone stock 2012 ML63 AMG with the M157, P30 PP, and I have a couple questions. A. what is "normal" boost pressure with the PP on the M157? I've read conflicting numbers; there's one thread here that says the PP should build 18.8 psi. I've read other threads that say that it's actually 1 bar (15psi). I would greatly appreciate a definitive answer from someone that has experience with what stock boost levels actually are. And then B. What are the common issues you've all experienced when your M157 isn't building the stock boost? Common boost leaks? Anyone experienced knock that limits boost and if so, what boost level did you experience being limited to? Here's where I'm going with all this: I have an AutoMeter Dashlink that I have setup to readout the boost pressure being reported to the ECM, and I'm only seeing a max boost pressure of 13 psi at WOT. Spark plugs were recently replaced, coil extensions were also replaced, no active or inactive engine codes present, I've tried 2 or 3 different brands of gasoline, doesn't seem to change (I do only have access to 91 octane in the state of Nevada, not sure if that's playing a part or not, but just thought it's an important piece of info) and I would really like to have the ECM tuned but don't want to spend $2k on a tune if there is an underlying mechanical/electrical issue limiting the engine from building the stock amount of boost.

I would greatly appreciate any assitance any of you may be able to provide.

Thanks!