Still very new to this,

I've been having some help from a forum member here to dial in my boost with feed forward, and got it pretty close to where it needs to be, need to widen the range of imx/drl for a revision soon.

Issue is, occasionally, during cruising or low load areas, I will lose throttle response and have to key off / key on and then it works immediately again.

1.8t with upgraded rods
k24 7400 turbo
1000cc ev14's @ 4 bar
fmic
walbro 450
s4 maf sensor

Attached is my log file exactly when it occurred (i truncated it because I was trying to recreate the issue, it was originally a 55mb file). It happens right around the 450 to 550 sample in the log

Hopefully I was logging the correct variables at the time to figure this out and give me somewhere to look.

I think I had this happen before on my other car and it was wiring to the throttle body, but that was a fairly stock car. Now that I've made all these changes and it's happening leads me to believe I fucked up somewhere. So has anyone had this happen?

ORI bin in robs post here: http://nefariousmotorsports.com/forum/index.php?topic=1204.0

I need to mention that I pulled DTC's and got the following, but it doesn't make sense with the maf or torque monitor because it happened at such low loads it's not like I was exceeding them at the time. Yes I know this needs to be addressed through IOP/IRL or reading the s4 wiki on torque monitoring again.

http://wiki.ross-tech.com/wiki/index.php/16487/P0103/000259
http://wiki.ross-tech.com/wiki/index.php/17963/P1555/005461
http://wiki.ross-tech.com/wiki/index.php/17743/P1335



Maps I've changed:
kfzwmn axis
kfzwmn varient axis
kfldrapp
lddimxn -> to 1's
mlhfm (s4 maf housing, a4 sensor)
kffdlbts
kfldbts
lamfa
tabgbts (actually not, when i modify it i noticed fuel request follows lamfa, need to look at this more, but bts is working for now)
ldrxn
ldrxnzk
kfldimx
kfldrl
kfldrq2
kfzwop/2 axis
kfmiop
kfmirl
temin
teminva
tvub
fkkvs
krkte
kfzw/2 axis + lower percent in high boost areas
kfdzk axis
lc+nls manually

Thank you, nyet.

I'll rescale my mlhfm and see if I can get it dialed in correctly.

Do you think that could cause a complete disconnect from throttle control?

So I scaled my MAF before I installed my turbo setup, I figured since i measured the housing directly and used the scaling program for bosch sensors that it would be correct.

Could it be because my maf sensor is so close to the filter that it's reading high?



full size: https://i.imgur.com/INo7HIh.png

Think I've figured it out.

To get my n75 dc to 95% during turbo spool up, I set my LDRXN to pretty high values, but it is not requesting any boost at low throttle pedal %'s, but the turbo was still spooling slightly and deviating from the requested amount, torque intervention would see this deviation, and cut throttle response. Does that sound right?

You can see this at the end of the 170714 log attached, which immediately cut throttle and I ended the log.

So this issue is related to my understanding of boost pid i guess, ha.

speaking of, I did some more logging and worked on my IMX/DRL some more, I more or less have boost under control, still needs some work but it's better than it was before, can be seen in the 180509 log attached.

also pretty sure i fixed the maf as per above.

It's a wideband ecu so I don't know if that has an effect on my krkte/fkkvs, but fueling still seems accurate, going to have to start over with fuel logging and adaptation values to be sure

Actually, that still doesn't sound right; mimax comes directly from ldrxn, so you actually want that to be higher than actual torque.

Log with those three variables added.

Well figured it out; reverted to a stock irl/iop and only adjusted the higher load areas.

No more epc.

Also figured out my imx/drl and am no longer over boosting.

Thanks for the help nyet, I don’t know when I would have realized my maf was incorrectly scaled, but car is running great. Now I can work on advancing timing.

That looks pretty damn good! Well done.