[340iexo]

Hey everyone, I am here to share my experience with my Gen 1 B58 issues. I have a FBO ‘18 340ix. Stock TCU and Stage 2 93 AGG OTS Map from Bootmod3.

TLDR; Misfires in Cylinder 3, then moved to 1 then 1 and 6. Replaced sparks and coils. Spark @ 0.022 gap Champion OEM. Cylinder misfires gone, except 6. Tried old spark on cylinder 6 and misfires cleared. Car idles perfect and runs great under 20% or less load. I’m stuck. Old plugs were gapped at 0.029 (factory spec)

Last Thursday, I got off work and went to get gas - filled her up and started it. Within 45 seconds I noticed my idle was just awful, sounded like choking and about to stall out. Restarted the car and it was still atrocious. Finished my commute home and by the time I pulled in, DING! CEL is flashing now. I then proceed to flash my stock map, and clear the codes (misfire galore on cylinder 3). The car runs good for the first 45 seconds, then right back to misfiring. Check the codes, and I get the first screenshot. Misfire directed to Cylinder 3.

From here, I need to isolate the issue - I do so by taking the ignition coil from Cylinder 3, and move it to Cylinder 1. I then take Cylinder 3 spark plug, move it to Cylinder 2. This will allow me to recognize injector failure, spark, or coil.

The code followed to Cylinder 1. I went ahead and ordered spark plugs before this happened, so I replaced those, but given my test - this is an ignition coil fault. Coil & Spark Plugs both replaced & with a gap of 0.022.

After installation of everything, TQd plugs @ 17 ft-lbs, we are still in a very peculiar spot…. NOW - there is no misfire, but HEAVY timing pull on WOT or 20%+ load….it WILL misfire on “cylinder 1” if I try to force the pull (bogs car very very hard) and drive train issue comes up. Clear code, and it’s gone, back to no misfire.

[SAKF_B58]

Sounds like you have a faulty fuel injectors. Whats the miles ? Stop driving it as you will end up causing more damage if you havent already.

[vektorprime]

Do you have stock HPFP? Or has it ever been replaced?

How about WMI?

In that last scenario, are you running stock tune and it still happens?

Are you also torquing the coils to spec? In the past I have over tightened these with no issue, but I believe it's supposed to be just something around 7lb.

[supremacyxi]

Sounds like a fuel related issue. I'd start with HPFP but it could also be an individual injector.

[Antwan340i]

Originally Posted by 340iexo

Hey everyone, I am here to share my experience with my Gen 1 B58 issues. I have a FBO ‘18 340ix. Stock TCU and Stage 2 93 AGG OTS Map from Bootmod3.

TLDR; Misfires in Cylinder 3, then moved to 1 then 1 and 6. Replaced sparks and coils. Spark @ 0.022 gap Champion OEM. Cylinder misfires gone, except 6. Tried old spark on cylinder 6 and misfires cleared. Car idles perfect and runs great under 20% or less load. I’m stuck. Old plugs were gapped at 0.029 (factory spec)

Last Thursday, I got off work and went to get gas - filled her up and started it. Within 45 seconds I noticed my idle was just awful, sounded like choking and about to stall out. Restarted the car and it was still atrocious. Finished my commute home and by the time I pulled in, DING! CEL is flashing now. I then proceed to flash my stock map, and clear the codes (misfire galore on cylinder 3). The car runs good for the first 45 seconds, then right back to misfiring. Check the codes, and I get the first screenshot. Misfire directed to Cylinder 3.

From here, I need to isolate the issue - I do so by taking the ignition coil from Cylinder 3, and move it to Cylinder 1. I then take Cylinder 3 spark plug, move it to Cylinder 2. This will allow me to recognize injector failure, spark, or coil.

The code followed to Cylinder 1. I went ahead and ordered spark plugs before this happened, so I replaced those, but given my test - this is an ignition coil fault. Coil & Spark Plugs both replaced & with a gap of 0.022.

After installation of everything, TQd plugs @ 17 ft-lbs, we are still in a very peculiar spot…. NOW - there is no misfire, but HEAVY timing pull on WOT or 20%+ load….it WILL misfire on “cylinder 1” if I try to force the pull (bogs car very very hard) and drive train issue comes up. Clear code, and it’s gone, back to no misfire.

Did you ever figure out what the issue was?

[Myles561]

O2 sensors

[dinan5m3]

Originally Posted by Myles561

O2 sensors

That's what happened with my case with Gen1 B58 after the shop damaged the stock O2 sensor (pre-cat) during install of AA catted DP. And the misfire wasn't really following anything from usual troubleshooting from moving the plugs and coils independently. Basically the misfires were showing in the fault codes on almost all cylinders Then the shop realized that the misfires started happening once the car goes into closed loop (whatever that means). Replaced with stock pre-cat O2 sensor, and did few WOT pulls with data logging with MHD. What a nightmare experience that was and now i know what a limp mode feels like. Never want to go through that again, at least not for a while.

[B58]

Originally Posted by dinan5m3

That's what happened with my case with Gen1 B58 after the shop damaged the stock O2 sensor (pre-cat) during install of AA catted DP. And the misfire wasn't really following anything from usual troubleshooting from moving the plugs and coils independently. Basically the misfires were showing in the fault codes on almost all cylinders Then the shop realized that the misfires started happening once the car goes into closed loop (whatever that means). Replaced with stock pre-cat O2 sensor, and did few WOT pulls with data logging with MHD. What a nightmare experience that was and now i know what a limp mode feels like. Never want to go through that again, at least not for a while.

Which brand oxygen sensor you get? OEM or like Bosch/NTK?

[dinan5m3]

Originally Posted by b58

which brand oxygen sensor you get? Oem or like bosch/ntk?

oem,

11-78-8-644-371 (g01)

[cfm56d7b]

Originally Posted by SAKF_B58

Sounds like you have a faulty fuel injectors. Whats the miles ? Stop driving it as you will end up causing more damage if you havent already.

When did the problem start to occur? For how long was the engine running fine with the mods listed?

These are the common components / sensors working together to manage fuel mixture delivery and ignition:

1. Spark plugs
2. Wires (don't forget to check these)
3. Fuel injectors
4. O2 sensor
5. HPFP
6. DME; the more expensive item if faulty

[Judelow36]

Originally Posted by 340iexo

Hey everyone, I am here to share my experience with my Gen 1 B58 issues. I have a FBO ‘18 340ix. Stock TCU and Stage 2 93 AGG OTS Map from Bootmod3.

TLDR; Misfires in Cylinder 3, then moved to 1 then 1 and 6. Replaced sparks and coils. Spark @ 0.022 gap Champion OEM. Cylinder misfires gone, except 6. Tried old spark on cylinder 6 and misfires cleared. Car idles perfect and runs great under 20% or less load. I’m stuck. Old plugs were gapped at 0.029 (factory spec)

Last Thursday, I got off work and went to get gas - filled her up and started it. Within 45 seconds I noticed my idle was just awful, sounded like choking and about to stall out. Restarted the car and it was still atrocious. Finished my commute home and by the time I pulled in, DING! CEL is flashing now. I then proceed to flash my stock map, and clear the codes (misfire galore on cylinder 3). The car runs good for the first 45 seconds, then right back to misfiring. Check the codes, and I get the first screenshot. Misfire directed to Cylinder 3.

From here, I need to isolate the issue - I do so by taking the ignition coil from Cylinder 3, and move it to Cylinder 1. I then take Cylinder 3 spark plug, move it to Cylinder 2. This will allow me to recognize injector failure, spark, or coil.

The code followed to Cylinder 1. I went ahead and ordered spark plugs before this happened, so I replaced those, but given my test - this is an ignition coil fault. Coil & Spark Plugs both replaced & with a gap of 0.022.

After installation of everything, TQd plugs @ 17 ft-lbs, we are still in a very peculiar spot…. NOW - there is no misfire, but HEAVY timing pull on WOT or 20%+ load….it WILL misfire on “cylinder 1” if I try to force the pull (bogs car very very hard) and drive train issue comes up. Clear code, and it’s gone, back to no misfire.

So i had a similar issue with cylinder 6, i swapped the coils on cyl#1 and 6, nothing changed, then i completely disconnected coil#6, still same, running on 5 cylinders, turned out to be a sparkplug

[Akshay918]

Hello
Changed injectors in my b58
Swap all old to new
Now the car misfires at idle only
But when you drive it there is no misfire at all