NefMoto

Hello,

I hope someone can help me, i have a CDL golf6 R20 engine with BT.
Calibrated 90 mm MAF and stops at 364 g/s and won't give more fuel from that point.
Anyone an idea how to fix it?
Can't find a MLMAX or something in software.
It is completly build engine with bigger injectors etc. 500+hp.

Johan

Either go larger MAF housing or run MAFless I'm afraid.

i can do this MAF housing and don't for bigger housing and adjust fuel so it will be ok, but than everything is off.
MAFless gives same issue.
I ran i mafless and starts leaning out over 1.7 bar.
So i thought i try to run a big MAF, but has exactly same problem.
At higher boost it goes to 25% lambda adaption and has max 6.88 ms injection time.

Johan

Are your injectors calibrated properly? What car and year are the injectors from?

Can you share a VCDS log with the following:

001
230
231

Also

001
031
101

Injectors are scaled right.
Special bigger injectors and bigger pump with special camlobe and roll camfollower.
Everything works perfect untill you try more boost.
Fuel pressure stays perfect at spec.
I hope i can get a solution to get max MAF value higher, if not i need to underscale the MAF i think...

Johan

Have you worked out your injector time relative to injector window? 

Um could you just change to a aftermarket maf? HPX pmas is used often on me7 stuff
Idk about med9.1

@Rick, yes should be ok.
Could this cause a problem like this?

@Carsinc, It doesn't matter how big your MAF is, if you calibrate it right the problem is always on the same point.
If you have a HFM5 and have 4V and make 300 g/s a MAF housing twice as big will give 300 g/s @ 2V.
And if limit is 364 g/s in the ecu it will hit limit at same hp.
If you don't correct MAF it will give half your flow and you can adjust fuel but all load calculation will be off..
Correct me when i'm wrong..

Johan

Your responses to my logging queries is "I think". If you can log those blocks, it'll give us an insight to what the car is doing.

will make some logs.

Johan

It sounds more like fuel starvation more than a MAF issue.

Rick

with underscaled MAF and 8 ms injection the lambda still is too lean on high rpm.
Back on MAFless again and more LP fuel pressure and lambda is getting better.
580 hp @ crank now.

Will do some more testing now..
Thanks for the help.

Have you adjusted injection advance? If using RS4 injectors, they don't mix properly and you end up with lean spots in the cylinder. Try fully advancing injection start time.

I run something bit bigger as RS4.
I tried 420 degree, 400 is stock.
Do you advance a lot more?

431 is is the maximum. I always fully advance at top end on bigger fuel demand setups as it gives you more of an injection window = more time to spray.

With RS4 or other injectors with sub-optimal spray, fully advance as soon as entering peak boost. With wrong spray pattern, the mixture isn't quite homogenous as it'll either spray outside the piston bowl or directly against the cylinder wall. Giving fuel more time in the cylinder allows more time to mix with the air for a uniform cylinder charge.

ok thank you for this info.
These injectors work quite well.
I had RS4 before and smoke a lot never get it completly right.

i added a bit of fuel duration with FKKVS.
If not fuel stops at 6,88 ms MAFless.
Runs quite ok now.
Ran 10.6 sec 1/4 mile last race, hope to make really low 10 next race.
Does anyone know what is quickest full FSI FWD in the world?

Johan

364g/s is only where VCDS maxes at, it won't display higher which is stupid. The MAF is still reading. My MAF maxed according to ME7 logger at 502.3g/s

The measuring block is limited by the ECU routine that injects that value onto the CAN bus. Without custom ASM code, you'll not see more than the measuring block can report.

Also, how did you get ME7L to work with MED9?

When fuel amount doesn't change from 364 g/s i don't think it is a diagnostic limit.
I don't believe that VCDS gives lower value as ME7L.
Or it reads different channel but than VCDS can also read that channel.

What software are you using to log this engine?

Surprise! ME7L does not read "diagnostic channels", it reads ram values directly. So yes, it is better. And it can't be directly compared to VCDS. Bottom line - it indeed could be other problem than "MAF maxing out".

Ok, i didn't know. Than it is better.
I thought i always gives ID bit for what it is, than how big steps are than actual value over diag and that it would be same for all diagnostic reading tools..

Dont forget KLTIKRPR.

What rail pressure are you tuning and how are you using the inlet cam for tuning,  the inlet cam also plays a huge part on the injection window and the cylinder pressure.