NefMoto

Always got into Soft Limp mode and it seems caused by throttle cut when the B_lambts kicked in - seems it persists with any map I tried.

This Thorttle cut/soft limp mode has been there since the motor got top overhaul 7 years ago- was just intended for polishing. Recently rechecked the CR and all chambers got 8.5 - 9.5 CR.

Some graphs, csv, and stock ecu bin are attached. I recently removed N112 and N249. Car is A3, 1.8T, AUM, AT, 150HP, 032LM, ME7.5.

Once I got this throttle cut gone on stock then I will start to follow s4wiki tuhing. Wanted to get the correct starting point first.

Please help.....

Check n75 and it's vac lines first
And  actuator leak test

All tested and looks good. I have spare n75, exchanged it, still same.

I read here in the other topic that it looks strange if the wgdc in full during boost ramp up and it seems happened here. How to fix it?

Sent from my ASUS_Z01RD using Tapatalk

provide a proper WOT log.

Put your n249 back in.

It's my attempt also to reduce leak risk by dismantling N249, but after reading around here and your direct advice seems I was in wrong direction. Will try to plumb it back in this weekend.

Read somewhere that 1.8T ME7.5 has bugs, I just wondered whether I hit a bug.

It's an attempt to WOT but got the cut before it's there then went into soft limp mode. Will log again with smoother ramp up.

Of course you didn't. That is utterly ridiculous.

That's utterly pointless. Not sure you understand the point to a WOT log.

DO NOT feather the throttle, we are trying to figure out what is going on with your boost control, not your throttle plate angle control

Pardon my ignorance. I got it now with gear2 and gear3 WOT - it got cut even before 10sec :(

No codes?

Thats not throttle cut. Thats a massive boost leak. Probably out your DV judging from your MAF readings.

I believe no code on Gear 2 and Gear 3. Got code below on Gear 4 when I got (hard) Limp mode; ASC light on, being AT stuck in Gear 4.

16486 -  Mass Air Flow Sensor (G70): Signal too Low
        P0102 - 35-10 -   - - Intermittent

Always got that code when I hit Limp mode; got no code on soft limp mode.

with some randoms map, I could reach 1.1 Bar (16 Psi) with 140s - 160s g/s MAF; but I need to carefully feather the throttle.

Coult it be MAP sensor faulty? I never replace it in this 7 years, might be it's now 17 y.o already (never changed at all).

Please just check your DV.

from last random map I logged

I have cleaned the DV also tried with blow to Atmosphere BOV from other car - got no luck :(

But, sure will recheck the DV also plumb back the N249 this weekend.

Thanks Sir for your help -- will get back once two things above done. 

Dont do this.

But yes, it is possible it is your MAF if you keep seeing that MAF too low code

No, no longer with that BoV. It was try and error :D

Current MAF just 2 months old and consistently reading 133 g/s on gear2 before getting cut.
 
Couldn't wait until weekend;
Did TIP check as I never done it before and it might be 17y.o. as well. Apperantly there is 2 quite big cuts there below Puck, seems rubbed down by the hot air from crankcase ventilation. Sealed it while waiting for the replacement arrive. Hope this is the culprit.
Plumbed back the N249.
Checked the DV seems stilll ok, try to push manually the valve still pushing back hard; but let's see whether i'll get check DV DTC later.
No chance to test yet.

--deleted this post, seems I accidenally quoted myself and posted, sorry :(

Managed to pull - now I got 164 - 169ish MAF reading. Lifted up because of traffic - hesitation in one of runs due to traffic as well;Don't want to break the seal either :D Darn that TIP leak!

Bunch of thanks Nyet! for insisting MAF reading problem, otherwise I would be lost again.

Wondering tho:
- what is the B_lambts active effect? I was suspecting it was a cause as cut happened after it's active - defintely wrong. Sorry, FR was too complicated to me and I only a car user.
- I was expecting 120ish g/s MAF (with no cut) as car spec was 150HP and all is stock except open air filter+N112 Delete (ESKONF & CWSLS update)+crank case ventilation to atmosphere (I took off the Puck, as it has no place at the moment). Why I got that 160ish MAF reading? forgot to mention that i have tightened the wg by 3 turns beside those 3 stuffs non stock.

--might be this topic needs to be moved to noob question now, as it's hardware issue instead of tuning--

B_Lambts

S4Wiki:
---------
LAMBTS
EGT enrichment tables:

• KFLBTS_0_A - requested lambda for component protection when calculated EGT (tabgbts_w) is above TABGBTS, modified by FBSTABGM, DLBTS, and KFFDLBTS.
  FBSTABGM (0x150C2) - KFLBTS multiplier. Make sure you change the axis properly to represent your lowered TABGBTS. Again, not necessary if you have a properly scaled MAF. Also, all ones in most files.
  [KF]DLBTS and KFFDLBTS - lambts = KFLBTS + [KF]DLBTS*KFFDLBTS. Therefore, setting KFLBTS to 1 where you don't need it won't disable bts, you also have to set KFFDLBTS = 0 as well.[23] Note that Mbox has DLBTS (2D), not KFDLBTS (3D).[24]
  TABGBTS - Threshold for KFLBTS. Unless calculated EGTs are above this threshold, KFLBTS is ignored. You may have to lower TABGBTS if you have a scaled MAF, since calculated EGTs will be artificially low.

The result is "lambts"
----------

--> so the B_lambts is condition for enrichment/make the above active/not to cut the throttle: CMIIW.

2. MAF Reading

S4wiki:
---------
--
Also, you should always compare msdk_w (alpha-n estimated air flow) vs mshfm_w (measured airflow). If they are different, you will likely need to adjust WDKUGDN and the VE model in BGSRM accordingly. This will ensure that if you unplug the MAF or it fails, the car will run properly in alpha-n.
--
Scale MLHFM (constant throughout scale vs stock!) to get your idle and partial short term fuel trims (STFT) near zero and your WOT AFR to roughly match your requested AFR. Another good MLFHFM sanity check is to log ps_w vs actual boost at WOT - ps_w should generally be slightly below actual boost. If it is over, your MAF is probably overscaled, and if you are running the stock MAP and not a 5120[10] hack, you run the risk of maxing out ps_w, which is a bad thing (see below).
----------

---> will log msdk_w and ps_w to check whether my MAF sensor needs scaling as the above (it's ITM brand if I'm not mistaken, was best available here locally that time of purchase, not genuine nor bosch oem)

Only bosch sensor will work properly.
As for bts, it's an enrichment based on calculated egt

You're wrong. lambts has nothing to do with throttle cut, unless the same root problem triggered both. I have no idea how you decided based on the description you posted how lambts is connected to throttle cut.


This is not something you should log to find out. You either got the right MAF or you didn't.

If the MAF you got isn't stock, you had better have a datasheet to go with it, or throw it away. It's useless. I have no idea how "its the best one i could find" makes any damn sense. It does not.

Thanks much Nyet, Fukenbroken - what knowledge I got here this time.

I did a run for mshfm_w vs msdk_w and ps_w vs plsol_w got as attached. And, yes, crappy MAF sensor - in some other high load high RPM (140-150ish g/s msdk_W)the reading became messy up and down, made me to lift up a bit to avoid limp mode due to hesitation.

A lot of chinese MAF product here and pretty difficult to get genuine BOSCH MAF, that's why I mentioned 'best I could find locally here' Anyway, I will find a new Bosch MAF before I move forward with tuning.

Thanks again!

Got the Bosch MAF and new TIP - Limp mode problem gone.
Started tuning with raising a bit KFZW and LDRXN only.
But, I got spikey MAF@throttleplate starting 5K RPM, was it ok or something not right? ::)

Looks more or less good except for the TB bit, post the log.

Here's the log. I got below error after the run - could it be the cause/related?

17524 -  Oxygen (Lambda) Sensor Heating; B1 S1: Open Circuit
        P1116 - 35-00 -   -

17511 -  Oxygen (Lambda) Sensor Heating; B1 S1: Performance too Low
        P1103 - 35-00 -

Yes. Stop logging or any other tuning until you fix all DTCs first.

Changed the Sensor. DTCs gone. Still got that oscilating MafAtThrottlePlate. What could be wrong? Appreciate any advice.

Do you have stock intake manifold btw?

Yes, intake manifold is stock

Please take a proper log.

3rd gear, 3000 rpm to redline, WOT. You're making it literally impossible to use the filters with that run.

Finally, the lde doesn't bother you at all in that small log you posted? And the fact that your wgdc is maxed out and you're still well short of requested boost?

I'm not sure what you're trying to do.

Between wastegate duty cycle, boost req, and boost actual...
I see that you have a massive boost leak and your pissing everything away, or your turbo is life of Elvis, gone

Or inlet collapsing, hard to tell

Made another run with some gear 3 pulls.

Yea, turbo is old, stock K03s. Rests is stock as well. Just wanted to max it out. She's just a daily city car with occasionally 150-200km trip. Planing to upgrade to K04 tho - when time and budget permit.

Anyway, for the moment, happy with her performance.

Thanks all, esp. Nyet, for helping me and her up to this state. Much appreciated. Otherwise I'd stay with that cut caused by that TIP big leak and bad MAF!

You have a massive boost leak.

Look at your lambda control.

Not sure whats the deal with the x axis on the graph you posted.