[mattypp]

Good Morning!!

I've been chasing a misfire in cylinder 1 in my 08 XI for a few weeks now and would love some input. The car has brand new plugs,eldor coils, VTT chargepipe and TIAL bov running a MHD stage 1 tune. The car threw the misfire code a few weeks back while driving it like a normal person. I went over the coilpack/plug and everything looked good. I cleared the code and went for a drive and under light acceleration it misfired in cyl 1 again. So I switched plugs/coilpacks on cyl 1 and 2 and the issues persists in cyl 1. Does this point to a bad injector(index 8)? if so, is there any way to log the car to ensure it's a bad injector?

I've attached the codes I'm seeing in MHD. I did some research on the shadow codes and I saw multiple times that folks typically ignore these? Is that accurate? Any help is greatly appreciated.

I did catch the misfire in a log too, just incase that's helpful - https://datazap.me/u/matthew-pinola/...og=0&data=3-24

[Saif2018]

Originally Posted by mattypp

Good Morning!!

I've been chasing a misfire in cylinder 1 in my 08 XI for a few weeks now and would love some input. The car has brand new plugs,eldor coils, VTT chargepipe and TIAL bov running a MHD stage 1 tune. The car threw the misfire code a few weeks back while driving it like a normal person. I went over the coilpack/plug and everything looked good. I cleared the code and went for a drive and under light acceleration it misfired in cyl 1 again. So I switched plugs/coilpacks on cyl 1 and 2 and the issues persists in cyl 1. Does this point to a bad injector(index 8)? if so, is there any way to log the car to ensure it's a bad injector?

I've attached the codes I'm seeing in MHD. I did some research on the shadow codes and I saw multiple times that folks typically ignore these? Is that accurate? Any help is greatly appreciated.

I did catch the misfire in a log too, just incase that's helpful - https://datazap.me/u/matthew-pinola/...og=0&data=3-24

Swap injectors from cylinder 1 to another and see if misfire follows.

[mattypp]

Originally Posted by Saif2018

Swap injectors from cylinder 1 to another and see if misfire follows.

Thank you! Looks like I'll need to pick up Carly so I can swap the injector values. I'll report back once I have an update.

[mattypp]

I did the old spark plug smell test and #1 stinks like gas. I'm just going to order an index 12 and call it a day. Thanks for the input Saif!

[Saif2018]

Originally Posted by mattypp

I did the old spark plug smell test and #1 stinks like gas. I'm just going to order an index 12 and call it a day. Thanks for the input Saif!

No worries mate, remember to replace seal and code the injector.

[mattypp]

Originally Posted by Saif2018

No worries mate, remember to replace seal and code the injector.

Is this the seal you're referring to? I thought a new injector would include this, no?

https://www.fcpeuro.com/products/bmw...ng-13537584315

[Saif2018]

Originally Posted by mattypp

Is this the seal you're referring to? I thought a new injector would include this, no?

https://www.fcpeuro.com/products/bmw...ng-13537584315

Yes that's exactly what I'm referring to. Bought mine separately, if it isn't included just buy it separately as it's pretty cheap.

[Maxmil982]

It turns out the solution is very simple. A 100k trim pot on each sensor signal wire (spots 19 & 20 on the large black subconnector). At 0% lots of false knock. And at 65% no false knock. Use one pot on each bank so they can be independently adjusted. Going too high will also filter out real knock & trigger a knock sensor too quiet code so you'll have to use judgement and trail & error if you choose to play around with this.