WHY is my 335i MISFIRING?... MSD80 Mosfet Repair

Today we're trying to fix the 30BB fault code on my 335i by replacing the mosfets on my MSD80 DME with the upgraded units. This is a common failure on 335i's produced between 2007-2008, and causes misfires on 3 cylinders and an internal fault code (either 30BA or 30BB).
This repair is easily done at home, or you can have a electronic repair shop do the work for you, but as we can see from my experience, results are not guaranteed! Now I'm left scratching my head, and wondering what the next step is. Stay tuned to find out what we do next!
Links below to the supplies used in this video.
Thanks for watching! Don't forget to check out The Bimmer Barn store to grab some merchandise, and get exclusive access to EXTRA content through our Patreon! :)
thebimmerbarn.com
/ thebimmerbarn
Note: This video description contains affiliate links. If you click on one of them and make a purchase, I may receive a commission. This occurs at no extra cost to you, but helps keep the channel going!
Upgraded FDB14N30 Mosfets - amzn.to/3zSK0VE (affiliate)
Hot Air Rework Station - amzn.to/2Y2g4c5 (affiliate)
63/37 Solder Paste - amzn.to/3kSFz8Z (affiliate)

[@Johnathan_Waters]

This video is going to unlock the ability for MANY e90 owners to totally destroy their DMEs!! Great job.

[@Notyourfathersbmw]

Just replaced my mosfets with help of this video. Fixed my 30ba code missfires 1,2,3 or dme fault . It was quite simple to do for how complicated it looked. (at least for me anything electrical scares me)

[@EvilX5M]

This is me too misfire Cyl 1, 2, 3 or DME. Car sounds like a tractor 😢

[@Notyourfathersbmw]

@@EvilX5M easy fix bro! Take your time and do it correctly do not break anything heat slowly and it will come right off. When you put new ones back on make sure you added enough heat so it locks itself in place with the solder paste. If you don't sit over it with enough heat the MOSFET will come right off . To check if it's secure I pulled on it with my tweezers just enough to know it was solid. Maybe watch a second video. I watched. A few before doing it.

[@Notyourfathersbmw]

@@EvilX5M I would offer to do it for you because I have exactly everything to do it again but we probably live too far

[@Lu-e]

To anyone reading this. When you solder the new mosfets sometimes on the first try, you will be able to start the car but it will still show injectors or DME codes. Go back and take your time making sure all your mosfets are solder correctly and that each pin is making contact 100%. It took me 2-3 tries to get the mosfets to work perfectly. If even after you try that then last thing would be the injectors are bad and you will need new injectors.

[@ilyld2003]

Very informative! Great content and really appreciate the step by step process. Makes the video very useful for troubleshooting and doing repairs myself!

[@scarface16134]

As a BMW tech DO NOT swap injectors without replacing the decouplers and seals!!!!! I often have to replace cylinder heads when people do this at the shop it's a 7k job! Please see ABR Houston's video on n54 injectors that covers this.... again do not follow those steps

[@marcussaiber6021]

Must say great thanks to all the folks of late apprising us of challenges associated w direct injection electronics ,updating software, coding and ECU replacement oh yeah and the CAS systems

[@scarface16134]

@@marcussaiber6021 direct injection deletes coming soon to an MHD near you

[@xjomuel]

I put new spark plug, coils and seals and decoupling to all index 12 and still misfire

[@scarface16134]

@@xjomuel might of been ovaled out from reusing seals. If there is sut past the seal the head is done....

[@romanleal3499]

Replacing the Ecu helped me and my friend. We replaced spark plugs, o2 sensors, the maf, swapped injectors, pulled the entire engine harness off to check for any wiring issues. We went down the line thinking we’d “save” money, but ended up wasting more at the end of the day.

[@Mr318live]

Just curious. What codes did it have on your car before replacing the ecu?

[@romanleal3499]

@@Mr318live It was just misfire codes on cylinders 4,5,6 I think

[@zachofalltrades6116]

how much did the new ecu cost and where you get it?

[@romanleal3499]

@@zachofalltrades6116 This was a while ago, before the huge inflation dilemma. I think it was anywhere from 1000-1200. This included the ecu obviously, programming, and the car needed to be tuned again due to it having upgraded turbos, bigger intercooler, and flex fuel.

[@sarockpashotan]

A great job honest man! I also agree about using flux with soldering paste. Good luck.

[@denisc2402]

Found this channel becoming my second favorite channel rn right behind m539 restorations

[@TheBimmerBarn]

Wow thank you! That means a lot to me, positive comments go a long way. We're taking this channel to the top!

[@951rollincivicsi]

Hey, great job on the video. I’m having a similar problem w bank 2 shutoff. All coils and spark plugs replaced. Do e60 m5 ecu mosfet go bad too?

[@jokerash]

L shape displaced Mosfets are for coils, top 6 mosfets in line are for injectors. You should swap all of them.

[@dominicbarne5218]

I always pre heat the whole board before I attempt a repair and have the board out of the case so you can heat the other side of the board for a minute with the rework gun, the misfire still present could be a few things, it’s a multi layer board so could have a power supply issue to that bank of mosfets or even processor damage, or an external issue just a case of process of elimination, if it’s dme failure upgrade to msd 81 it’s much stronger, love the content 👌🏻

[@TheBimmerBarn]

Thanks Dominic! Yeah I'm going to have to go down that path. Get a dme, have it cloned, etc. Thanks for that knowledge about the board! It was weird how it didn't have any "failed" mosfets so it probably wasn't the issue to begin with.

[@stephanelouvet1113]

Dude, your channel is gold ! I learned a lot about 335i -> before

[@LuisGonzalez-ph8zp]

I did a tune on mine stage 1+ had misfires on 4,5,6 went bought NGK coils and NGK plugs thinking it would fix it ran code reader turns out my mosfets blew out 🤦🏻‍♂️ now I’m waiting on the DIY kit so I can fix my ecu dammmmnn.

[@marlboro14100]

Great video bro, very real person not others making video said they changed this and that and cut the video ohh its working yuhooo but the truth they can't fix it. just for content only. Thank you and godbless i hope you fix the problem

[@FTN-tx6ok]

Thanks for making this video. I really wanted to see you do this. I'm sorry it didn't fix the misfire. I'm struggling with my e 46 to get it to stop misfiring. It's almost always cylinder 5 and have done everything I can think of including new injectors. I get a rich code sometimes too. Last thing I can do is replace O2 sensors and do a vamos rebuild. I don't think that will be the fix but want to do the vanos anyway for fun. Good luck on finding the problem. Keep up the great content. Your videos are very informative. Thanks!!

[@zachofalltrades6116]

did you ever get it fixed mine is misfiring only in cylinder 5 as well , ive change spark plugs, coils, injectors, valve cover gasket and still chasing it

[@romanleal3499]

@@zachofalltrades6116 I’ve seen some cases where the pin that holds the disa valve will come off and get stuck in either cylinder 5, or cylinder 6 intake valves. It’s a good idea to pull off the intake manifold and look to see if the valves aren’t caught up on anything. If the pin is stuck, try your best to pull it. I’ve never had a case where the intake valve was damaged.. all should be good if you successfully remove it

[@FTN-tx6ok]

@@zachofalltrades6116 Sorry, no I haven't. Project has been on hold for a while. I'm down to thinking it could be the cat clogged. But that's just throwing a dart at the problem. If you get yours figured out let me know.

[@rileythebeau9345]

Also the dme. Each coil is ran by a transistor that literally melt off the board sometimes. Pick up an ews deleted DME and plug it in. Most common failures are 2 & 5 for the dme transistors

[@AnythingEverythingGh]

How do you identify a mosfet on a control board and how do you buy some online? Which store?

[@pugs1377]

Bummer. Couirous to see what the fix is

[@94tontonche]

Hello, I have a 325i 2010 N53 slows down unstable and shakes when cold, it lasts 1 minute and afterward the car runs very well. When she does that I accelerate slightly and that prevents the shaking and slows it down unstable, do you have any idea, said the vanos? No smoke, no smell of gasoline. New spark plug and coil. I'm French, sorry for the translation.

[@matthieumangar5534]

hello after repairing the mosfets my n54 starts with difficulty with misfires on several cylinders I need your help. help me please

[@user-bk9yy5pf2w]

Were you able to find the problem? I am experiencing the same issue. DMW was sent out and came back fine. I swapped the injectors and still getting the same code.

[@Salman-sc8gr]

Wouldn't you test the Mosfets that run injectors?

[@petercarvo8320]

You should have replaced the coil packs with the new ones and also put a new spark plugs first. That would’ve been the simplest way narrow it down. And I would highly recommend draining the fuel out and adding you if you were adding some type of an additive to bring the octane level back up to where it needs to be and removing any water from the fuel tank.

[@jacoblami1731]

Won't fix a 30BB code unless the entire bank went at once which is almost unheard of. Usually what happened if this repair doesn't fix your problem alone is the MOSFET goes and takes an injector with it.

[@user-oe9un7fj6e]

Hello! I have the same exact issue with my car. Can you please share how you ended up fixing the car?

[@TheBimmerBarn]

Replaced the dme, and a few injectors 👍

[@Notyourfathersbmw]

I ran into an interesting problem today. I went WOT then all of a sudden "boom" huge backfire then 30ba-dme injector 1,2,3 or dme internal fault. That's the only code. Just replaced the injectors withing a year so now I'm leaning towards dme fault aka mosfets need to be changed out. What do you think?

[@TheBimmerBarn]

If your car is pre-2008, sounds like it could be the issue. At WOT, you're putting the most electrical load on the mosfets as they surge with power as fast as possible to power the injectors/coils. Check out my msd81 upgrade video to see how to find a cheap one!

[@Notyourfathersbmw]

@@TheBimmerBarn thank you for the reply. I bought the exact mosfets kit you had in the video. Let's hope it fixed the problem 🤞

[@swiftyrpm1460]

@@Notyourfathersbmw were you able to resolve your issue? I ran into the same issue.

[@Notyourfathersbmw]

@@swiftyrpm1460 yes it fixed the issue.

[@Jerry_from_analytics]

Maaan, videos like this are a direct result of KZbin removing dislikes.

[@eztrash4903]

idk if u replaced the DME and/or if u ever fixed it. but on mesfet for cyl 4, it seems u ripped the motherboard layiing which is very important. the way mother boards are made, they are layers of sheets and if u rip threw the layers u cut the conductivity threw a path way (wire). otherwise i feel like this woulda been a good job done\. iv done a few mosfets and u did a good job from everything else i saw.

[@eztrash4903]

also to be noted, their is ofther failures on the dme so as mosfet repair for injectors isnt a end all be all. i thinki its like the power supply transistor. just something else to keep in mind.

[@robertstone6275]

Wondering if you have a plugged cat on that bank, or too much oil intrusion from the valve cover. Certainly would cause misfires since your DME doesn't appear bad.

[@TheBimmerBarn]

It ended up being the DME, for some reason fixing the mosfets did not resolve the issue. But in the next episode we upgrade to MSD81 and started making progress towards fixing the misfires!

[@markmurphy9280]

Good job, you could have used a dremel type tool to grind down some of the graphite, Less heat needed. Anyway, Subscribed.

[@MrGlitchxFTW]

based on some experience, i will go ahead and try to diag this situation, but i will advise to first to pull out the valve cover and clean up the surface, the oil could be clogging up some of the injectors with a mix of oil, although oil smoke isn’t present through the tailpipe it can probably be causing the injectors to not perform as they should, once cleaned reinstall the cover try your buddies injectors, and see if its still the issue, if still present than the DME took a poop, upgrade to MSD81, MSD80 in those cars are out of date. Hope the car gets back and running 🙏🏼

[@TheBimmerBarn]

I'll be taking off the valve cover because it's leaking, but I agree I think it's the DME. Hopefully runs good once we fix that!

[@MrGlitchxFTW]

@@TheBimmerBarn goodluck brotha

[@danc2014]

Injectors and coil have a mosfet to drive them. You only did the coil. The dme can also be bad.

[@YewoMwafulirwa-gt2wn]

Nice

[@BMWExcluserviceRockville]

Small tip. Next time remove the circuit board from the housing as the heat sink in the housing was drawing the heat from your air heater.

[@mikealkarout9555]

Great tip

[@trevorcharlery3777]

you need to check you wiring loom from dme to injectors and coils as i found out the hard way.

[@elliottstanaway2]

Meaning you had a bad wire?

[@uschifickstuck3418]

How did you solve the error or what was defective?

[@TheBimmerBarn]

New DME unfortunately. Couldn't get the old one to work.

[@uschifickstuck3418]

@@TheBimmerBarn I desoldered and renewed two mosfet. Now the BMW is running again. The whole thing cost me €5. Thanks.

[@uschifickstuck3418]

All mosfet must have the same ohm resistance at the end when measuring.

[@dedrickbellinger7291]

Dme could be bad. I had the same issue until I replaced the dme on the same cylinders

[@TheBimmerBarn]

I think I agree 😥

[@snhongo1]

Mostly one can never have a good reading if the mosfets are still on the circuit board, the best way to test them is to make sure each comes out in one piece then test it separately that way you can really know if it was dead so that you can really know that might were the problem was....otherwise you replace already working mosfets,,,and the other thing I noticed is that if the old original ones have no problem its best to put them back because they are genuine these days after market products are very unreliable....and also mosfets should never be touched with bare hands when new, I m sure most know that....

[@brocklittle5491]

You should have practiced first before this. Some of those pins are hanging on by a thread. You bought flux but I barely saw you use any. It’s super important to distribute heat evenly while soldering

[@jkperformance6785]

Ever figure it out ?

[@An0nDEViant]

Dme is fried. Only supposed to have a reading on one post left or right of the center pin.

[@sherdonphiri6723]

Please help me guys am in need of those MOSFETs of BMW injectors .am in south Africa Johannesburg and there is no place to get them around. Please anyone to assists on getting them guys

[@rayray3009]

I would pull the plugs and replace them. Then swap the coils around. We had a truck that acted a lot like this and it turned out to be a clogged cat.

[@Jay-pd6vi]

Didn't think so..... You'll get it can't be nothing crazy thought maybe injectors but we cleaned them and how they look now was within a matter of weeks after.

[@Jay-pd6vi]

Also having Both Lean codes on my black E46 you seen I've done every thing still lean +27 percent.

[@TheBimmerBarn]

replaced the MAF, and oxygen sensors? could be dirty injectors, bad fuel pressure, or air leak in the intake manifold.

[@Jay-pd6vi]

Lol done all I even have 1 piece Silcone boot I swapped my buddy's maf and had no change so don't plan on wasting money. Just had manifold off and did all silcone hoses for brake booster and more, at this point I'm wasting money but it's driveable 137k.

[@hansjrnandreasen5867]

Nine out of ten times its the injectors leaking fuel on the spark plugs when you have misfire

[@eugertbolo8636]

Do one good thing for your self. Don't say a liear any more, which is; you know what you do

[@bradhawking8076]

Why post a video if it didn't fix anything? Troubleshooting completely out of order, don't believe everyone's misinformation. SMD board repair? was this your first experience doing board repair? Surprised no contact pads were ripped from the board when removing. Fyi most mosfets will either look or smell fried and can confirm by it testing open or shorted.

[@jasonking8812]

Dme is bad I've had several failed with exactly the same fault codes won't be injectors

[@Findingmatteo]

I have the same code on my n54 you think it’s the dme not injectors ?

[@earalmurray8982]

I’ve just had tmw dmes fried in the last two days did you ever figure it out? An did you change coils

[@jasonking8812]

@@earalmurray8982 yes new coils and the later ecu with updated drivers sorted the issues

[@xConundrumx]

lordy lordy, nope that is not how you test mosfets, o my lord and it went off the deep end after that ... nope ... I am out.

[@sagitaroore]

This video 7 years ago would save me the bouchiting of slaughter house mechanic that charge me 5 thousand in repair only to be the 1 Moffett in the middle they make u change everything on the car to find the real problem smh stay away from mechanics

[@iG4MERs]

Do an MSD81 Upgrade!

[@CarlosTorres-zx1yb]

Why would you post the video acting like you know what you’re talking about even tho it didn’t fix the issue? How are going to give advice on this repair when you can’t even successfully repair it

[@brianholland4133]

Because tons and tons of b54 owners can see how to do their mosfet upgrade so their dme works. This video is fantastic. Only person who doesn’t know anything is you, haha. And anyone else pissing and moaning.

[@brianholland4133]

N54*

[@adamsoloman5291]

Bro you have way too much time on your hands

[@adamsalum9181]

Program on dme...

[@careytreesh4583]

Check the source pin of those 3 mosfets. make sure they all connect to ground, also use a scope to check all 6 gate pins. if bank 2 is mising it could be the parts just before the gates.

[@jdmtechllc6589]

@@careytreesh4583 I can tell you know exactly what you are talking about

[@careytreesh4583]

@@jdmtechllc6589 thanks. been doing mosfet repair work for about 5years now.

[@jdmtechllc6589]

@@careytreesh4583 want to repair one for one of my clients?