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aPuppy187 aPuppy187 is offline
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Car: 2009 BMW 335i Sedan
Default Misfires Under WOT MAP5 - 09-22-2020, 04:45 PM

I have a manual 2009 335i and have been experiencing misfires during WOT after going FBO and running a JB4 set to map 5.

Before going full bolt on I never experienced misfires outside of the rough cold starts(details later). On the stock tune as well as map 1 the car runs perfectly fine and does not experience any sort of misfire (excluding cold starts). I am in California and am running 91 Octane (lame I know) from Chevron (I always use either Chevron or Shell). The car performs beautifully on map 5 and pulls very strong most of the time but every once per dozen or so pulls it will misfire, I will hear a backfire, and then the car will run very roughly (presumably misfiring) until I turn it off. If I immediately turn the vehicle back on after this the misfiring will not persist and the car will run perfectly fine. I can do a pull where it starts misfiring, turn the car off and back on again, then do another pull immediately that works perfectly fine and doesn't cause a misfire event.

Reading the ECU codes after a misfire event reveals that several cylinders are all misfiring. A somewhat odd thing is that I have experienced 2 different sets of cylinders misfiring together. The first few time this happened I found that cylinders 4,5,6 were misfiring but then other times I have found cylinders 1,2,3,5 were misfiring. I have also recently seen a code 29DC for Cylinder Injection Switch-Off happen independent of getting the misfire codes, one time this was accompanied by code 2B2C No Description Found.


ECU Codes:
29CD Misfirings, Cylinder 1
29CE Misfirings, Cylinder 2
29CF Misfirings, Cylinder 3
29D0 Misfirings, Cylinder 4
29D1 Misfirings, Cylinder 5
29D2 Misfirings, Cylinder 6
29CC Misfirings, Several Cylinders
29DC Cylinder Injection Switch-Off



To add some context, for the past year I have been experiencing rough cold starts, large fluctuations in RPM and the engine seemingly almost dying as it dips below 550 RPM. After about 10 or so seconds the car will mellow out and idle nicely. This only happens after the car has been sitting for 12+ hours. I have never experienced a long crank and the engine has always started right up, albeit with a rough idle. My close friend has a 2008 335i and was experiencing similar issues that were resolved by replacing his HPFP. From my research these symptoms can also be caused by leaky injectors so I'm not sure which is actually causing the issue.

My 335i has just over 80K miles on it. I've owned it for about 2 years now and bought it with 69K. The interior and exterior are in excellent condition and I've never had any mechanical issues with it before now so I assume it was taken care of well by the previous owner. I am not sure if the injectors or HPFP have ever been replaced.


Mod List:
JB4 Gen5 with Bluetooth
VRSF ***-less ***
VRSF High Flow Silicon Inlets (factory location)
VRSF High Flow Aluminum Outlets
VRSF 7.5" Stepped Intercooler
VRSF Lower Charge Pipe
VRSF Charge Pipe
Turbosmart Raceport GenV
BMS DCI
VRSF Oil Catch Can
NGK 2-Step Colder Spark Plugs Gapped to 0.020"
New OEM Ignition Coils

All of these mods were installed during the last month. Aside from a walnut blasting a few weeks ago I have done all of the work on the vehicle myself and have double checked that all of the new parts were installed properly before posting.
Attached Files
File Type: csv P32_M5_R2_200922_1434.csv (90.3 KB, 17 views)
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aPuppy187 aPuppy187 is offline
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Default 09-23-2020, 10:19 AM

I spent some time last night collecting more logs and had several instances of pretty bad misfiring while logging. If there is any more info or logs that I can provide, please let me know.
Attached Files
File Type: csv P32_M5_R26_WOT-_200922_2149.csv (390.6 KB, 17 views)
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aPuppy187 aPuppy187 is offline
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Default 09-23-2020, 04:47 PM

I have some new logs to share. It seems like the issue only occurs after driving for some time, I would suspect that this is heat related but I'm not sure.

You can see that in the early pulls of this log, my hpfp is running strong and always above 10. Then in the last few pulls it seems that my hpfp dips down to as low as 3. The weird part is that during the pull before the last one the hpfp was strong and stayed above 11 then a few seconds later when I made the last pull of the log the hpfp nosedives. I also noticed that the trims are really low during the last pull when the hpfp nosedives.

As far as I understand, if your hpfp ever dips that low during WOT it's going bad and needs to be replaced. Is my hpfp the issue or is there something else at play here?

I also took a photo of my OLD spark plugs (1-6 from left to right) that I replaced when doing all of my mods about a week ago. Some of the tips look fouled so maybe there are injector issues here as well?
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File Type: csv P32_M5_R15_WOT-_200923_1527.csv (473.9 KB, 18 views)
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Default 09-29-2020, 12:06 PM

HPFP looks to be tired, which would explain the sporadic issues.

Are the plugs wet?


Burger Motorsports
Home of the JB4 the worlds most popular turbocharged tuning system!

It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please click here for more information on legal requirements related to use of BMS parts.
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aPuppy187 aPuppy187 is offline
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Default 09-29-2020, 12:25 PM

The old plugs weren't wet when I removed them. It had been sitting with the battery disconnected for about a week when I changed plugs so I'm not sure how that plays into this.

I also noticed that the FP_L was dipping into the 40s at times. As far as I understand, if the issue is the LPFP I should be seeing the FP_L dip before the FP_H dips. Since it appears that the FP_H is dipping first I assume it's my HPFP struggling to keep up with the higher fuel requirements. Ando from BMS looked over my logs and thought that the LPFP also looked tired. I ordered a stage 2 LPFP along with the flex fuel kit from Fuel-It that will be here tomorrow, I wanted to go e85 anyways so I was just happy to have an excuse to upgrade sooner. I also ordered a HPFP, low and high pressure fuel sensors, and a set of index 12 injectors from FCP Euro. My plan is to swap the LPFP first, and if that doesn't fix the issue then swap the HPFP and sensors. I'm pretty confident that the issue I'm seeing isn't caused by my injectors but I'm hoping to fix my rough cold start issue with those.

I'll post a follow up with the results after I install everything and get some more testing done.
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Default 10-03-2020, 05:58 AM

Quote:
Originally Posted by aPuppy187
The old plugs weren't wet when I removed them. It had been sitting with the battery disconnected for about a week when I changed plugs so I'm not sure how that plays into this.

I also noticed that the FP_L was dipping into the 40s at times. As far as I understand, if the issue is the LPFP I should be seeing the FP_L dip before the FP_H dips. Since it appears that the FP_H is dipping first I assume it's my HPFP struggling to keep up with the higher fuel requirements. Ando from BMS looked over my logs and thought that the LPFP also looked tired. I ordered a stage 2 LPFP along with the flex fuel kit from Fuel-It that will be here tomorrow, I wanted to go e85 anyways so I was just happy to have an excuse to upgrade sooner. I also ordered a HPFP, low and high pressure fuel sensors, and a set of index 12 injectors from FCP Euro. My plan is to swap the LPFP first, and if that doesn't fix the issue then swap the HPFP and sensors. I'm pretty confident that the issue I'm seeing isn't caused by my injectors but I'm hoping to fix my rough cold start issue with those.

I'll post a follow up with the results after I install everything and get some more testing done.


Burger Motorsports
Home of the JB4 the worlds most popular turbocharged tuning system!

It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please click here for more information on legal requirements related to use of BMS parts.
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