NefMoto

Hi,

I've found out that after TFSI coil converstion my car (basically two cars) have problem with ignition and therefore with starting when the voltage drops to 8.5V+- while cranking. ECU seems to get sync because it starts injecting fuel and rpm (about 150rpm) can be observed in me7logger. Tsrldyn is 3.5ms. After helping main battery with connecting other battery to get about 9-10V while cranking, the spark appears and car starts... Does someone have similiar problem?

I have never had this problem at all. Matter of fact fsi coils require less dwell then stock coils. ether you have shit china coils or you have a problem with power distribution / ground issue with the car 

Yeah, normal issue in cold weather (e.g. -10C and below), also had the same problem on 2.2T when dwell was not adjusted in ECU. Because the dwell time is way too high and it gets exponentially too high with the battery voltage being lower, so it literally just kills the battery charging the coils.

Look a little more at ZUESZ, the standard tsrldyn calculation is not used during starting IIRC.

You must correct all the maps:
KFTSRL
KFSZDUB to have the correct correction same as on a TFSI.
And then also especially KFSZT, this one is used <800 rpm during cranking. Look what happens at 8V and below, it's way way too high for TFSI coils.
FSZTM multiplies it even higher at low temperatures.

Look how it's done on TFSI and correct all these maps to be the same, not just KFTSRL as you probaly have done, or if you didn't correct anything, then it's just stupid because the TFSI coils fail quite fast with the too high dwell time!

Thanks for reply, prj. Actually I left KFTSRL stock and corrected KFSZDUB a litte because when the dwell time is ~2-2.5ms, they generate a lot of noise on the radio. Idk why but they are doing it since they are new. Its beru ZSE033.

I corrected KFSZT (actually done it before, but I thought that dwell time was too short). Now I reducted it to ~4ms/8V and FSZTM to 1s. Now I'm waiting for the cold night to test :)

Btw I see that when the baterry is really low (like 8V during cranking) the rpm is lost and regained every ~0.5s (so is sync I think). Its really strange because starter can still maintain like 90-100rpm then..

Instead of random adjustments, you should take the maps from 2.0 TFSI MED9.
There is nothing to tune or adjust there. Use the OEM values. You will not do a better job!
Only if at extremely high load there is issues (I am talking 2.5 bar boost or more), then it might be needed to increase dwell at high RPM.

On 2.2T my experience was that the excessive charging of the coils was the reason the battery voltage dropped so low.
They create a huge drain if you try to dwell them for 18ms.

I never had issues on any ME7 because when I started with ME7 I already knew about this issue due to previous 2.2T experience and I directly took the values from MED9.

Yes, but as I've said, when copying over values from MED9 coils generates noise in radio (and probably other wires in the car, haven't check with osciloscope yet). I dont know why, because coils are new, like 100km.

Right now I've changed only values for KFSZT and FSZTM to get similiar dwell time during cranking as in MED9. Stil waiting for battery to be drained of power, to check it out. But now I can say that it start a lot faster with battery charged.

Btw. Should I disable lastdyn?

lol, that means you have ground loop in your radio.
Correct engine operation is more important than your radio, which can be fixed.

His cranking voltage is also shit.  There are other electrical issues.

Radio is 100% stock ;) And the coils seems to be emitting noise through the air, bacause wrapping coils with aluminium foil seems to solve the problem. Just checked lol.

Usually its like 10-11V. But I want the car to start after staying a week in -10 degree weather...

Stock or not stock, you have a wiring problem somewhere.
And you should be using OEM values for the coils. IDK what you are trying to argue about.
Done tons of cars with TFSI coils never had any radio issues, maybe because the wiring wasn't fucked on them.

Not necessarily. Due to the aggressive dwell time the car does not start after voltage drops to a certain point.
Like it goes to 9.5V - 10V and then the coil dwell does the rest.

Offtopic

Parking on MS AGH does not forgive haha