[El-daybed]

I have an 08 335xi stage 1 mhd 91 oct and i have been getting a cylinder 4misfire on cold start , i replaced the injectors and plugs and have tried swithtching around coils and using different ones injector is brand new from fcp euro with about 20 miles on it and it seems like its leaking but ive swapped about 4 different index 12 injectors thinking it was them, will pull plugs before i start the car and are dry and look fine, after about 30 seconds after starting car will misfire i pull plugs again and are soaked in gas and black , i am at a loss please help!!😭



hpfp, lpfp ,lpfp sensor cyl 1-3-4-5-6 index 12 injectors and plugs all new

[Bimmer_Bro]

Originally Posted by El-daybed

I have an 08 335xi stage 1 mhd 91 oct and i have been getting a cylinder 4misfire on cold start , i replaced the injectors and plugs and have tried swithtching around coils and using different ones injector is brand new from fcp euro with about 20 miles on it and it seems like its leaking but ive swapped about 4 different index 12 injectors thinking it was them, will pull plugs before i start the car and are dry and look fine, after about 30 seconds after starting car will misfire i pull plugs again and are soaked in gas and black , i am at a loss please help!!😭



hpfp, lpfp ,lpfp sensor cyl 1-3-4-5-6 index 12 injectors and plugs all new

Which map version of MHD are you using ?

[El-daybed]

Originally Posted by Bimmer_Bro

Which map version of MHD are you using ?

V9.0

[Bimmer_Bro]

Originally Posted by El-daybed

V9.0

Try V7 or V10 just to rule out the map. You could also try turning on the cold start noise reduction in the MHD options.
Cold start is just to warm the cats for emission purposes. Some people having cold start misfires have had this solved by enabling this option.
My car idled terrible on V9. V7 or the new V10
Seem much better.

[El-daybed]

Originally Posted by Bimmer_Bro

Try V7 or V10 just to rule out the map. You could also try turning on the cold start noise reduction in the MHD options.
Cold start is just to warm the cats for emission purposes. Some people having cold start misfires have had this solved by enabling this option.
My car idled terrible on V9. V7 or the new V10
Seem much better.

Thank you!!! super helpful , didn't even know there was a 10.0 will try tmo morning

[Bimmer_Bro]

Originally Posted by El-daybed

Thank you!!! super helpful , didn't even know there was a 10.0 will try tmo morning

Sounds good and no problem. It's a easy thing to try before throwing more money at the car. V7 was always my favourite but recently switched to 10 and it seems good so far.

[El-daybed]

Originally Posted by Bimmer_Bro

Sounds good and no problem. It's a easy thing to try before throwing more money at the car. V7 was always my favourite but recently switched to 10 and it seems good so far.

I have updated to v10 and swapped around injectors coils and plugs, and still as if injector #4 was leaking , still getting cold start misfires will pull plugs and are fine and dry before car starts then are black and wet after about 45 seconds of running, the cold start noise reduction did help a little bit but still misfires

[Bimmer_Bro]

Originally Posted by El-daybed

I have updated to v10 and swapped around injectors coils and plugs, and still as if injector #4 was leaking , still getting cold start misfires will pull plugs and are fine and dry before car starts then are black and wet after about 45 seconds of running, the cold start noise reduction did help a little bit but still misfires

How many miles on the car and have you ever done a walnut blast?

It's wet due to the miss fire / limp mode. This tells you nothing so don't worry about it. If they are dry and fine from the car sitting then it's not a leaky injector.

[El-daybed]

Originally Posted by Bimmer_Bro

How many miles on the car and have you ever done a walnut blast?

It's wet due to the miss fire / limp mode. This tells you nothing so don't worry about it. If they are dry and fine from the car sitting then it's not a leaky injector.

Hit 130,000 yesterday walnut blasted around 1k or less miles ago with new intake gaskets

[Bimmer_Bro]

Originally Posted by El-daybed

I have an 08 335xi stage 1 mhd 91 oct and i have been getting a cylinder 4misfire on cold start , i replaced the injectors and plugs and have tried swithtching around coils and using different ones injector is brand new from fcp euro with about 20 miles on it and it seems like its leaking but ive swapped about 4 different index 12 injectors thinking it was them, will pull plugs before i start the car and are dry and look fine, after about 30 seconds after starting car will misfire i pull plugs again and are soaked in gas and black , i am at a loss please help!!😭



hpfp, lpfp ,lpfp sensor cyl 1-3-4-5-6 index 12 injectors and plugs all new

Also we're the injectors probably coded in when you installed them? Dumb question but it's important.

[El-daybed]

Originally Posted by Bimmer_Bro

Also we're the injectors probably coded in when you installed them? Dumb question but it's important.

Yes they were

[Bimmer_Bro]

Originally Posted by El-daybed

Hit 130,000 yesterday walnut blasted around 1k or less miles ago with new intake gaskets

Was the misfire happing before this service was done or only after?

[El-daybed]

After

[El-daybed]

Originally Posted by Bimmer_Bro

Was the misfire happing before this service was done or only after?

What service?

[Bimmer_Bro]

Originally Posted by El-daybed

What service?

Did this misfire only start happening after the walnut blasting and intake gaskets ?

[El-daybed]

Originally Posted by Bimmer_Bro

Did this misfire only start happening after the walnut blasting and intake gaskets ?

No misfire started happening about 3 or 4 weeksago after i finished installing all the injectors

[Bimmer_Bro]

Originally Posted by El-daybed

No misfire started happening about 3 or 4 weeksago after i finished installing all the injectors

Well I'm stumped also. I think next step is you need to do a data zap log with MHD when the car is idling Cold.

[El-daybed]

Originally Posted by Bimmer_Bro

Well I'm stumped also. I think next step is you need to do a data zap log with MHD when the car is idling Cold.

How do i log idling

[Bimmer_Bro]

Originally Posted by El-daybed

How do i log idling

If you have the monitoring module with MHD. I think you can just start and stop a log any time.

[El-daybed]

Originally Posted by Bimmer_Bro

If you have the monitoring module with MHD. I think you can just start and stop a log any time.

I do but it only starts when in like 60% throttle i dont know how to start it otherwise

[Bimmer_Bro]

Originally Posted by El-daybed

I do but it only starts when in like 60% throttle i dont know how to start it otherwise

Oh shoot I'm not sure either. You could ask in the MHD look at my log thread.

[El-daybed]

Originally Posted by Bimmer_Bro

Oh shoot I'm not sure either. You could ask in the MHD look at my log thread.

Link?