[Chrisguilday]

Hey guys, there’s a guy on a fb group that is trying to diagnose a problem with his car, and I’m trying to help.

He has a stage 2+ N54 335i that he bought already tuned in June, and it just recently started misfiring on #6

I’ll give more context below, but first here’s my question: If it’s not the coil or spark plug, and say it’s a fuel issue, will live data tell you fuel trim levels per cylinder or just overall? Trying to determine if it’s the fuel injector. Is that one way to diagnose it? I have a OBD2 scanner that will display live data and fuel trim levels but I’m not sure if that means it will tell you trim levels per cylinder or if that’s even a thing / route to diagnose this issue.

He brought it to two mechanics and they failed to diagnose the problem. I assume they swapped the coils around / checked the plugs, but he doesn’t know.

So essentially I told him to swap the coils and see if the misfire follows the coil, and to also check the spark plug / swap the spark plug and check if it’s OEM as they need to be colder spark plugs and gapped correctly. He doesn’t know what plugs are in there. And then if neither of those help, I was thinking reading the live data could help? But I’m not sure.

Thanks!

[Bimmer_Bro]

Originally Posted by Chrisguilday

Hey guys, there’s a guy on a fb group that is trying to diagnose a problem with his car, and I’m trying to help.

He has a stage 2+ N54 335i that he bought already tuned in June, and it just recently started misfiring on #6

I’ll give more context below, but first here’s my question: If it’s not the coil or spark plug, and say it’s a fuel issue, will live data tell you fuel trim levels per cylinder or just overall? Trying to determine if it’s the fuel injector. Is that one way to diagnose it? I have a OBD2 scanner that will display live data and fuel trim levels but I’m not sure if that means it will tell you trim levels per cylinder or if that’s even a thing / route to diagnose this issue.

He brought it to two mechanics and they failed to diagnose the problem. I assume they swapped the coils around / checked the plugs, but he doesn’t know.

So essentially I told him to swap the coils and see if the misfire follows the coil, and to also check the spark plug / swap the spark plug and check if it’s OEM as they need to be colder spark plugs and gapped correctly. He doesn’t know what plugs are in there. And then if neither of those help, I was thinking reading the live data could help? But I’m not sure.

Thanks!

First off colder plugs are not needed for stage 2+ MHD maps. Oem bosche 3 prong work great and no need to gap.

Best way to check for a leaky injector is let the car sit overnight.
Do not start the car. Then pull out cyl 6 plug and see if it's wet with gas and smells of fuel.

When was the last time the valves were Walnut blasted? That could also be the issue.

[Chrisguilday]

Originally Posted by Bimmer_Bro

First off colder plugs are not needed for stage 2+ MHD maps. Oem bosche 3 prong work great and no need to gap.

Best way to check for a leaky injector is let the car sit overnight.
Do not start the car. Then pull out cyl 6 plug and see if it's wet with gas and smells of fuel.

When was the last time the valves were Walnut blasted? That could also be the issue.

Ah ok gotcha. So no benefit for checking live data? I’ll let him know what you said and hopefully that will help. On the topic of spark plugs, I just installed a catless DP, and I have a charge pipe, and just tuned the car to MHD stage 2+ yesterday, it runs great. However, I also bought 1 step colder spark plugs, but I haven’t installed them just yet. Putting those plugs in is better than leaving the OEM ones though, right? These are the plugs https://www.ecstuning.com/b-ngk-parts/performance-iridium-spark-plugs-97506-set-of-six/97506kt/

Also, since you seem knowledgeable I thought I’d ask: Any idea why tuning my car is causing a PCV / valve cover leak? It happened when I first tuned it to stage 1+, then kinda went away, then yesterday I tuned it to stage 2+ and it had an immediate squeal that was worst than before, almost sounds like a bad pulley bearing. I mean it made the noise the second I started pulling out of the driveway before I even hit 5 MPH. Doesn’t make any sense… Why would that happen?

I diagnosed it as a valve cover leak because if I take the oil cap off the squeal goes away. It does it most often if I blip the throttle once the RPM’s drop. I initially thought the burble tune caused it (and maybe it did) but it’s very weird that it happened again RIGHT after tuning it before I went over 5MPh, and it got quite a bit worst. However after driving it 10 ish miles I’m not hearing it happen nearly as much. Weird.

[Bimmer_Bro]

Originally Posted by Chrisguilday

Ah ok gotcha. So no benefit for checking live data? I'll let him know what you said and hopefully that will help. On the topic of spark plugs, I just installed a catless DP, and I have a charge pipe, and just tuned the car to MHD stage 2+ yesterday, it runs great. However, I also bought 1 step colder spark plugs, but I haven't installed them just yet. Putting those plugs in is better than leaving the OEM ones though, right? These are the plugs https://www.ecstuning.com/b-ngk-part...f-six/97506kt/

Also, since you seem knowledgeable I thought I'd ask: Any idea why tuning my car is causing a PCV / valve cover leak? It happened when I first tuned it to stage 1+, then kinda went away, then yesterday I tuned it to stage 2+ and it had an immediate squeal that was worst than before, almost sounds like a bad pulley bearing. I mean it made the noise the second I started pulling out of the driveway before I even hit 5 MPH. Doesn't make any sense… Why would that happen?

I diagnosed it as a valve cover leak because if I take the oil cap off the squeal goes away. It does it most often if I blip the throttle once the RPM's drop. I initially thought the burble tune caused it (and maybe it did) but it's very weird that it happened again RIGHT after tuning it before I went over 5MPh, and it got quite a bit worst. However after driving it 10 ish miles I'm not hearing it happen nearly as much. Weird.

Live data would only be helpful from the O2 sensor but that would be for the full bank. So you could see if that bank is slightly richer than bank 1. The physical spark plug check method is the best to start with.

I honestly would not put them in. If gapped correctly they will work fine, but just not needed. I have seen plenty of guys here chasing misfires and it was all due to dialling in the gap on NGK plugs. I am full bolt on MHD2+ 93 map and I use oem plugs and coils. Never had an issue. It just takes the guess work out. I would only go colder on a custom tune if instructed by the tuner.

Ken at wedge performance makes most of the maps for MHD. He tests them all on his own cars first. He stated a few weeks ago that he has really come to Dislike NGK plugs due to their low OHM rating. Bosche plugs work perfectly fine with his tunes on MHD.

You may have a valve cover gasket leak if removing the oil cap causes the sound to change. Or you can try replacing your pcv valve first. I like the RBturbo ones.

[Chrisguilday]

Originally Posted by Bimmer_Bro

Live data would only be helpful from the O2 sensor but that would be for the full bank. So you could see if that bank is slightly richer than bank 1. The physical spark plug check method is the best to start with.

I honestly would not put them in. If gapped correctly they will work fine, but just not needed. I have seen plenty of guys here chasing misfires and it was all due to dialling in the gap on NGK plugs. I am full bolt on MHD2+ 93 map and I use oem plugs and coils. Never had an issue. It just takes the guess work out. I would only go colder on a custom tune if instructed by the tuner.

Ken at wedge performance makes most of the maps for MHD. He tests them all on his own cars first. He stated a few weeks ago that he has really come to Dislike NGK plugs due to their low OHM rating. Bosche plugs work perfectly fine with his tunes on MHD.

You may have a valve cover gasket leak if removing the oil cap causes the sound to change. Or you can try replacing your pcv valve first. I like the RBturbo ones.

Thanks for the info!

I guess I’ll keep the OEM plugs for now. Everyone else has told me that I should swap them as the OEM plugs don’t dissipate the heat as much, and therefor could possibly cause pre-detonation / knock to occur. But I’ll hold off for now, or maybe get the plugs you referenced.

And yeah, I bought a new valve cover already. I’ve had it for about a month, but never ended up swapping it because 4-5 days after I tuned it to stage 1+ the PCV leak stopped happening. It’s weird because the same thing is happening again: The more I drive the car after the stage 2+ tune the less often it happens. It only happens now if I blip the throttle in neutral. So strange. Maybe in a few days it will stop completely like last time lol.

Last question if you don’t mind, is there any concerns / disadvantages to running an E30 mix? Can I just go fill up with 30% ethanol and re-tune it? Is there enough fuel left to handle more boost on the MHD E30 tune?

[Bimmer_Bro]

Originally Posted by Chrisguilday

Thanks for the info!

I guess I’ll keep the OEM plugs for now. Everyone else has told me that I should swap them as the OEM plugs don’t dissipate the heat as much, and therefor could possibly cause pre-detonation / knock to occur. But I’ll hold off for now, or maybe get the plugs you referenced.

And yeah, I bought a new valve cover already. I’ve had it for about a month, but never ended up swapping it because 4-5 days after I tuned it to stage 1+ the PCV leak stopped happening. It’s weird because the longer I drive the car after tuning it to stage 2+ the less often it happens. It only happens now if I blip the throttle in neutral. So strange. Maybe in a few days it will stop completely like last time lol.

Last question if you don’t mind, is there any concerns / disadvantages to running an E30 mix? Can I just go fill up with 30% ethanol and re-tune it? Is there enough fuel left to handle more boost on the MHD E30 tune?

I think the oem plugs are rated for close to 475 hp so most MHD maps would have no issues. These OTS maps are pretty safe and conservative. Colder plugs would be great for more aggressive tunes or if you were chasing down some timing corrections that's would be something to try. It's a pretty common misconception that colder plugs are "needed" for MHD. Just make sure the coils and plugs are not too old. Tunes put more stress on the ignition system so they will need to be replaced more often than stock.

I am no ethanol expert as we don't have e85 in Canada. That being said i believe you have to upgrade you fuel pump if you want to run E.