TRM

but we also logged a rather strange boost graph. Actual Boost was greater than Requested Boost!

Thomas (not sure of his AW handle) did the logs for me and should be emailing them soon. he pulled codes and i was getting Bank 1 and Bank 2 "To Lean" DTC's. it wasn't consistent though. after the second run (on the track) in limp mode it only through a Bank 1 DTC.

to see what the MAF was doing we then did two runs in 3rd gear from 2k rpm to 7k rpm.

i'm x-chipped and my peak MAF readings between 5000 and 7000 rpm were around 180...much to low for an x-chip i believe.

kinda like the dark blue line on patterson's graph.

<img src="http://pictureposter.audiworld.com/18887/current_maf.jpg">

we surmised this is why i was soon to experience limp mode after he would clear the codes. which i am now greatful of since limp mode is preferred over detonation. ;-)

i'll either try to swap in a known good MAF from Matt's car or just buy a new one and be done with it.

not sure what to make of the actual boost being greater than requested...i've never seen this before and neither did Thomas. perhaps it's time to send my ECU to AWE for the latest revision of x-chip?

'Nova more S4

any intake mods?

TRM

nope. bone stock intake. i cleaned the MAF last week prior to this as well

Mark P

I seem to recall some discussion that the "requested" is not really an actual indication of "requested". ie, nothing is really striving to meet this requested.

Instead, what happens, is that the software is tuned to run a particular way. The changing of that software does not automatically change this "requested" curve that you are seeing. The software(programming) changes will alter the "actual" values, of course. But the tuner also has to change this "requested" curve to match the programming that s/he did. If they don't change this informative requested curve, then it won't match their programming and won't match the actual values.

I'm not 100% sure on this, but I seem to recall a discussion similar to this.

I also note in APR's ECU Explorer, they label these two "Desired" and "Actual". The term "desired" seems to follow this thought that it's more "informative" of what the programming should be like, as opposed to a "requested" value that the "actual" is trying to achieve.

Still not sure though

TRM

sounds reasonable. thanks Mark.