Car Running Lean on Boost (Data Log)

[Pasteurised]

So i did a third gear pull and got this crappy data log from my BLuetooth OBD2 adapter:

 

[<tuffty/>]

Guessing whoever mapped it forgot to do the fuel... need to see what the requested AFR is but that will need a registered copy of VCDS

<tuffty/>

 

[badger5]

I would imagine timign pull on 020 is high if you're also only got 8 deg of timing in there..
looks like a crap map if lamfa is set to std levels still. Sadly see it often..

Hot hot and crack tastic is the usual result of this tuning approach

 

[Pasteurised]

Its strange, did another pull and got these results:

 

[badger5]

vcds ftw
proper logs
requested and actual afr's on 031 block

 

[<tuffty/>]

Its strange, did another pull and got these results:

The 11's are most likely EGT protection kicking in... not really surprising considering the map appears to be giving all the boost and non of the fuel

Ignition timing is suffering as a result too...

<tuffty/>

 

[Stuart B]

Its strange, did another pull and got these results:

I am far from experienced - but I have noticed the more sensors being read at once the less accurate they are especially in real time logging.

 

[<tuffty/>]

I am far from experienced - but I have noticed the more sensors being read at once the less accurate they are especially in real time logging.

Its not less accuracy as the reported data is correct but bluetooth comms like this are laggy and resolution is very low... even using VCDS on k-line is slow and resolution drops hence having to do runs in lower gears...

K-Line is slow as f00k comms wise...

<tuffty/>

 

[Pasteurised]

Yea when i try 8 sensors it only gets new data every 4 seconds, but with 4 sensor it gets data every 1 second.
Been running this map for over a year lol
Am I correct that these cars are fitted with an 80 lph fuel pump?

 

[Stuart B]

standard S3 8L is a 4 bar fuel pump and 3 bar fuel pressure regulator.

I need a new 3bar FPR as with my 3 bar FPR my (ebay ECU) struggles to get full power and feels dogppoop - so I still have a 3.5 bar FPR on. Some maps do require > 3 bar FPR for some reason.

to be fair - if its been okay a year - find something else to resolve your boredom?

 

[<tuffty/>]

If the map is asking 22psi of boost but still only on factory fuelling its a **** map... I'd be getting it logged properly in the first instance to establish exactly whats going on and confirm..

Mapped cars need the afr to be 12.5 on boost to keep them happy, factory fuelling is 14.7 afr even under boost until component protection kicks in and adds all the fuel (like your second log)... this is a very bad way to tune...

Faulty fuel pumps normally start off fuelling fine but go leaner than requested afr higher up the revs as the fuel pump can't keep up

You won't be able to diagnose that with a phone app

<tuffty/>

 

[Pasteurised]

Yea im going to invest in better logging equipment, the logs are so inconsistent:

 

[<tuffty/>]

Yea im going to invest in better logging equipment, the logs are so inconsistent:

Its lack of context data thats the problem not inconsistency... this type of fuelling is indicative of component protection... it won't come in at a specific point as its based on certain factors to do with intake temps, knock and egt's... generally gets earlier and earlier as the engine gets hotter and more pi**ed off...

High boost and no fuel in your first (assuming coldish) log is indicative of where the map is... the rest is the engine getting hot and the ECU trying to protect it

<tuffty/>

 

[Stuart B]

its interesting your first log had a MAF reading of 207 and since then nowhere near that? again maybe related to the logging.

 

[<tuffty/>]

its interesting your first log had a MAF reading of 207 and since then nowhere near that? again maybe related to the logging.

Excess of fuel (evident by the low 11's afr) kill turbine speed and subsequently airflow

<tuffty/>

 

[Stuart B]

blimey, there's no winning here is there not enough fuel it burns up, too much fuel and it loses performance.

I see why you need to have it custom mapped by a professional for each individual car's setup, hardware and condition - a tiny adjustment could make all the difference - for engine safety and beating the Golf R up the slip road.

 

[Pasteurised]

Yea in my first log at around 5800rpm its 13.8afr an 18psi flowing 207g/s
Then the latest is 5800rpm 13.5afr but only 12.7psi flowing 178g/s

 

[<tuffty/>]

Ignition timing pull looks to be pretty high on yours too... timing advance is low in your logs, should be well in the teens but is around 8 degrees... means its possibly pulling loads... need to log CF's in block 20 with VCDS

<tuffty/>

 

[Pasteurised]

Yea will be investing in VCDS for sure.
Just checked, its only 3.5degrees advance on the latest log at 5800rpm, so that accounts for the difference in airflow then/power.

 

[<tuffty/>]

Timing advance generates torque which of course results in power...

<tuffty/>

 

[Pasteurised]

Yea so basically like you said at first, the fueling is **** and the car is freaking out trying not to die.

 

[<tuffty/>]

Pretty much...

<tuffty/>

 

[Pasteurised]

Thats more like it:

4bar fpr added

 

[<tuffty/>]

ECU will adapt the difference out... pointless exercise fitting a 4 bar plus extra strain on the pump

You need to see requested fuel but like I said based on the first log your map looks be to all boost no fuel... no idea what mods you have but that stage 2 + boost levels and seems very aggressive so not a good place for std rods if thats what you have

<tuffty/>

 

[Pasteurised]

oh well, worth a try lol, VCDS is on its way.

 

[desertstorm]

By the sounds of it even when you have logged it with VCDS the map you have on the car appears to be pretty poor. Probably better to spend the money and get it to a tuner who knows what he is doing who can sort this out for you.

 

[Pasteurised]

All sorted, vac leaks everywhere, at the DV, FPR, and through the PCV system. All hoses replaced, car running sweet now.

 

[Stuart B]

how did you find a vac leak on the FPR ? have you replaced the 4bar FPR with a 3bar FPR after fixing the vac leak?

 

[Pasteurised]

It was the vac hose running from the inlet mani to the fpr that was leaking, just removed it and used a hand pressure tester on it.
Ive just left the 4bar in for now, the car feels much better with it.

 

[<tuffty/>]

Feels better because you fixed the original issue... swap it back to the 3bar dude... you also narrow your window for fuel trim adjustments as the ECU will adapt out the extra fuel provided by the higher pressure... you have +/- 25%... it will adapt out at least 15%

<tuffty/>

 

[Stuart B]

Hi Tuffty, some older maps do require 4bar FPR. That JBS 280bhp package needed a 4bar FPR and additional pump. Is it possible some of these distance generic maps and ECUs still need one? My ECU requirements didn't come with a requirement for a 4bar FPR but it definitely is more responsive with a 3.5 bar than the existing 3bar FPR or a replacement.

Original 3bar FPR 180 g/s
New 3bar FPR 195 g/s
New 3.5bar FPR 199 g/s

What's weird with my ECU is the boost pressure is lower ~18psi my old one was more like an aggressive 21psi peak, but the wheel torque and wheel bhp are more 250/250 than the Stage 1 ECU 240/240. Almost as if they are trying a safer map, I don't yet have an FMIC but I don't believe that will suddenly make a higher boost.
I can occasionally get a higher boost, maybe the turbo is just a bit tired?

 

[Pasteurised]

Thought id update this now that its sorted, in case anyone has the same issue.

Turned out to be the map, the LAMFA table was stock on 0.95 lambda at WOT, the solution, either pay someone to sort the map, or sort it yourself if you're confident

 

[badger5]

simples to adjust lamfa..

 

[Pasteurised]

Yea, i had a backup ecu just incase though haha.
Added launch control too, but will probably never use it!

 

[Stuart B]

put in the back up ECU then and show the same tables - it will be really interesting.

my Stage 2 ECU I bought seems incredibly cautious in comparison to the original Map. it is producing more power, torque and MAF g/s etc but with less boost.

 

[Pasteurised]

Main differences are in KFMIRL and KFMIOP which relate to load request and load map, and obviously the component protection points are raised.