Coil issue? Sporadic ignition cut

[happykriss]

Hi everyone!
I have an AAN powered S2 coupe that recently started playing with me.
I upgraded to TFSI coils recently and a day or two later it started cutting ignition.
You can drive for a while then it just dies a second. I have noticed the RPM needle have dropped a couple of times, but i thought at the beginning it was a failure in the instrument. Still not sure if this is connected with my issue.

I've replaced both sensor at crank without any improvement.
I pulled an extra ground to the coil for safety, but no difference.
Only error i got is:
Engine speed sensor (G28) Sporadic- implausible signal

This is NOT the standard "Engine not running" fault code (Correct me if i'm wrong) so i'm starting to believe there is a interference with the signal due to coil pack.

This is my one and only car at the moment so all help is really appreciated.

[mike74]

Ignition switch playing up?

[happykriss]

Maybe. I tried wiggling the key a little while driving but no difference. Not sure if that would be considered a good way to test it though. Think i need to check my groundings.

[RichLV]

What spark plugs do you run? Had the same issue when swapping to TFSI coils. Turns out my 3 month old F5DP0R's started misfiring, but it wasn't a light misfire, it was like a complete cut across all cylinders. And because of the violent car shaking that happened during misfires I got all kinds of mystical fault codes - G40 bad, G4 bad, G28 bad etc. Swapped the plugs and it all went away like never happened.

[happykriss]

What spark plugs do you run? Had the same issue when swapping to TFSI coils. Turns out my 3 month old F5DP0R's started misfiring, but it wasn't a light misfire, it was like a complete cut across all cylinders. And because of the violent car shaking that happened during misfires I got all kinds of mystical fault codes - G40 bad, G4 bad, G28 bad etc. Swapped the plugs and it all went away like never happened.

Hi, thank you. I believe i used F5DP0R but not sure.
May i ask what you swapped them with?

[RichLV]

Just to test I swapped my old NGK PFR7Q plugs in. Car started to go like a charm. Right now I'm rocking NGK BCPR7ET.

[happykriss]

Just to test I swapped my old NGK PFR7Q plugs in. Car started to go like a charm. Right now I'm rocking NGK BCPR7ET.

Thank you for your input. I will try some other plugs tonight.

[RichLV]

Keep a spare coil in the glove box. Because of incorrect dwell timing, these can die fast.

[happykriss]

Keep a spare coil in the glove box. Because of incorrect dwell timing, these can die fast.

I will do that. They have been on my VEMS powered S4 engine and worked well there for the last 10 000km. Is it Bosch ECU that kills it?

[RichLV]

Yep, too much dwell time on Motronic, they tend to overheat. Don't cover them.

[happykriss]

I swapped the plugs for some Denso IU22 today as we got them at work for a good price.
Can anyone tell me why the old are brown? Boost leakage or heat that make them look like this?

[RichLV]

Dunno about the insulation but by the looks of the tips you're running rich. All black and sooted.

[happykriss]

Going to install af gauge soon. Know its a little to rich, but not sure what to do about it.

Sent fra min SM-N910F via Tapatalk

[RichLV]

Most likely an air/vacuum leak after MAF. PCV system check would be the first I'd check. I had problems with the Check Valve hose, it was hand made from 2 hoses.

[mike74]

^^^ agree. You've probably got the infamous 00561 mixture adaptation code too
Boost leak test time!