Injectors or MOSFET??

edf8fde · 03-07-2018, 08:55 PM

Hey guys. I know this has been run through before, but it never hurts to get personal input. Today I was accelerating into a lane with basically 100% throttle. It was a normal pull for about 3 seconds and then there was almost a "boom" and the engine light came on and the car would idle at like 450rpm and almost die. Had no power and was misfiring. Luckily I was a block from home and drove carefully back. Read the codes and came back with:

29cc - Combustion Misfire several cylinders
29cd - Combustion misfire cylinder 1
29ce - Combustion misfire cylinder 2
29cf - Combustion misfire cylinder 3
30ba - Injectors 1,2,3 or DME, Internal fault.

I'm fairly sure it's the MOSFETS but would the entire bank 1 go like that?

Let me know what you think, thanks. All the plugs and coils are fairly new.

RSL · 03-07-2018, 09:20 PM

2012 shouldn't have a problem with MOSFETs. Injectors are always a potential, but probably not likely in this case.

If you're on the stock charge pipe, check it at the throttle body. If it's solidly attached, check the rest of your IC piping. "Boom" during boost is something under pressure letting loose.

edf8fde · 03-07-2018, 09:21 PM

Sorry, its a 2007 335ix. I just took it out of my bio. It wasn't an actual explosion, just a solid jerk and instant misfire.

RSL · 03-07-2018, 09:48 PM

In that case, MOSFETs definitely move up the list. Not sure on the “boom” though, unless it was something related to a cut. I’ve hit some limiters accelerating WOT that felt like rear-ending an invisible car at 50mph lol

Not that big a job to pull the DME to confirm or rule it out and they're way cheaper than injectors, so I'd start there. I'd give the physical stuff under the hood a once-over first though, just to make sure the boom wasn't something else.

YoungBlood · 03-08-2018, 12:19 AM

My mosfets went on a rather spectacular fashion (5k rpms, wot in third) there was a bang and the car cut off. Only ran on one bank when I tried to start it back up

edf8fde · 03-08-2018, 12:23 AM

Basically, the exact same thing happened to me! Just ordered new MOSFETS for 10 bucks. Hoping this will fix it and not have to pay 850 for new injectors. Thanks for the response.

RocketSurgeon · 03-08-2018, 03:47 AM

It's almost certainly MOSFETS.
An injector failure is very different, one cylinder cuts out and you get injector codes.
When you see 30BB or 30BA on a car made before 03/08, it's almost always MOSFETS. Fortunately it's a relatively inexpensive repair.

feuer · 03-08-2018, 07:20 AM

Quote:

Originally Posted by RocketSurgeon

It's almost certainly MOSFETS.
An injector failure is very different, one cylinder cuts out and you get injector codes.
When you see 30BB or 30BA on a car made before 03/08, it's almost always MOSFETS. Fortunately it's a relatively inexpensive repair.

Not every 30bb and 30ba can be repaired with Mosfets replacement. Been there. I know. Also, thankfully not very often, when the Mosfets burn they damage the injectors too. So potentially could turn into expensive repair quickly.

edf8fde · 03-20-2018, 10:16 AM

Replaced all 6 mosfets. Cleared codes and car runs better than ever. It is strange, I have never felt my car run this well. Almost leads me to believe that mosfets can degrade over time. Probably just placebo though. Thanks for all of the input!

shaginwagon13 · 03-20-2018, 12:35 PM

Quote:

Originally Posted by edf8fde

Replaced all 6 mosfets. Cleared codes and car runs better than ever. It is strange, I have never felt my car run this well. Almost leads me to believe that mosfets can degrade over time. Probably just placebo though. Thanks for all of the input!

Any chance you can link to the mosfets you ordered? I think I need to replace mine as well.

edf8fde · 03-20-2018, 01:11 PM

https://www.digikey.com/products/en?...DB14N30TMCT-ND

Make sure you get the FDB14N30TMCT-ND not the FDB14N30TM

shaginwagon13 · 03-20-2018, 02:14 PM

Quote:

Originally Posted by edf8fde

https://www.digikey.com/products/en?...DB14N30TMCT-ND

Make sure you get the FDB14N30TMCT-ND not the FDB14N30TM

Thanks so much. I am going to place the order now.

LOL $13 for all 6 mosfets instead of buying a new DME for $1,300.

GEOS07335i · 03-22-2018, 01:42 PM

Where did you take it to replace the MOSFETS? How much did it cost?

catcher22 · 03-22-2018, 02:05 PM

My DME MOSFETS blew up 2 months ago in a similar fashion.

I basically have no experience with electrical engineering and didn't trust any local TV shops (the few that are left) to work on this DME, most likely for the first time, so I sent it off to:

https://n54dmerepair.com

It's $250 for the service, which depending on how you look at it could be a steep price or not. Remember, a new one costs upwards of $1500.

Sure, the MOSFET parts are $15, but it's also very easy to destroy the DME if you don't know what you're doing or don't have the proper tools.

The service was well worth it, all 6 MOSFETS were replaced, tested, and my car has been running great since I got the DME back a month ago. Basically plug back in, and play!

feuer · 03-22-2018, 02:24 PM

$250 for repairs on MSD80 is way too much. It should be around $80 to $120 max. MSD81 upgrade runs about $400-450 for used part and programming. If you want to keep MSD80 buy Mosfets and have any TV or computer repair shop to swap them for you.

catcher22 · 03-23-2018, 05:35 PM

Quote:

Originally Posted by feuer

$250 for repairs on MSD80 is way too much. It should be around $80 to $120 max. MSD81 upgrade runs about $400-450 for used part and programming. If you want to keep MSD80 buy Mosfets and have any TV or computer repair shop to swap them for you.

How did you even determine those numbers? No real point in spending hundreds and the coding effort for an MSD81 if the original can be fixed. The MSD81 isn't really an 'upgrade' either (it's basically the same exact ECU, just a different part due to the recall).

There are several options with varying convenience, risk, and price. Like I said, I just went through this a couple months ago and I couldn't be happier with my decision.

Of course it always depends on how cheap you want to be with the repair.

feuer · 03-23-2018, 06:06 PM

Quote:

Originally Posted by catcher22

How did you even determine those numbers? No real point in spending hundreds and the coding effort for an MSD81 if the original can be fixed. The MSD81 isn't really an 'upgrade' either (it's basically the same exact ECU, just a different part due to the recall).

There are several options with varying convenience, risk, and price. Like I said, I just went through this a couple months ago and I couldn't be happier with my decision.

Of course it always depends on how cheap you want to be with the repair.

I repair cars. Prices are based of half a dozen ECUs I had to rapair or replace. So they are pretty accurate. Failed msd81 vs msd80 falling rate is pretty much non existant. I haven't come a cross a single failed msd81. I'm glad that you are happy but $250 for msd80 repair is awfully high. I would sent out to repair two of them and even turn profit.

lee.j.hill · 03-14-2022, 06:43 AM

was this thread for a msd81

I have just had 30BA cyclinders 1,2,3 and i have a msd81

Mustafa.e92 · 03-14-2022, 09:27 AM

Quote:

Originally Posted by lee.j.hill

was this thread for a msd81

I have just had 30BA cyclinders 1,2,3 and i have a msd81

msd80 as mentioned many times

C4maro · 03-14-2022, 01:29 PM

Are mosfets something to do as preventative maintenance on a stock n54?

Sgop335 · 03-14-2022, 06:09 PM

One could by replacing the mosfets. My e60 stranded me. But the issue is it can be mosfets or power supply. In my case the mosfets tested fine so wouldn’t have helped

TiAg740 · 03-15-2022, 02:28 PM

Posting to get more access to my newbie profile. 2008 e92 335i ~70,000 miles. I had a mosfet issue. My codes were similar and when it went I thought something went in the engine, fairly violent. Got replacement mosfets via digikey via YouTube video suggestion for similar pricing as above and had a local audio repair shop that I take amplifiers to replace them for $60. Less than 10k miles since replacement, still good
with many WOT pulls.

03-07-2018, 08:55 PM	#1
edf8fde Private 22 Rep 72 Posts Drives: 335is manual Join Date: Dec 2016 Location: Scottsdale, AZ iTrader: (0)	Injectors or MOSFET?? Hey guys. I know this has been run through before, but it never hurts to get personal input. Today I was accelerating into a lane with basically 100% throttle. It was a normal pull for about 3 seconds and then there was almost a "boom" and the engine light came on and the car would idle at like 450rpm and almost die. Had no power and was misfiring. Luckily I was a block from home and drove carefully back. Read the codes and came back with: 29cc - Combustion Misfire several cylinders 29cd - Combustion misfire cylinder 1 29ce - Combustion misfire cylinder 2 29cf - Combustion misfire cylinder 3 30ba - Injectors 1,2,3 or DME, Internal fault. I'm fairly sure it's the MOSFETS but would the entire bank 1 go like that? Let me know what you think, thanks. All the plugs and coils are fairly new.
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03-07-2018, 09:20 PM	#2
RSL Captain 650 Rep 779 Posts Drives: E92 ///M3 (Retired) / 335is Join Date: Mar 2012 Location: USA iTrader: (6)	2012 shouldn't have a problem with MOSFETs. Injectors are always a potential, but probably not likely in this case. If you're on the stock charge pipe, check it at the throttle body. If it's solidly attached, check the rest of your IC piping. "Boom" during boost is something under pressure letting loose.
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03-07-2018, 09:21 PM	#3
edf8fde Private 22 Rep 72 Posts Drives: 335is manual Join Date: Dec 2016 Location: Scottsdale, AZ iTrader: (0)	Sorry, its a 2007 335ix. I just took it out of my bio. It wasn't an actual explosion, just a solid jerk and instant misfire.
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03-07-2018, 09:48 PM	#4
RSL Captain 650 Rep 779 Posts Drives: E92 ///M3 (Retired) / 335is Join Date: Mar 2012 Location: USA iTrader: (6)	In that case, MOSFETs definitely move up the list. Not sure on the “boom” though, unless it was something related to a cut. I’ve hit some limiters accelerating WOT that felt like rear-ending an invisible car at 50mph lol Not that big a job to pull the DME to confirm or rule it out and they're way cheaper than injectors, so I'd start there. I'd give the physical stuff under the hood a once-over first though, just to make sure the boom wasn't something else.
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03-08-2018, 12:19 AM	#5
YoungBlood LongDongSilver 274 Rep 706 Posts Drives: e90 335i Join Date: Mar 2016 Location: Utah iTrader: (2)	My mosfets went on a rather spectacular fashion (5k rpms, wot in third) there was a bang and the car cut off. Only ran on one bank when I tried to start it back up
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03-08-2018, 12:23 AM	#6
edf8fde Private 22 Rep 72 Posts Drives: 335is manual Join Date: Dec 2016 Location: Scottsdale, AZ iTrader: (0)	Basically, the exact same thing happened to me! Just ordered new MOSFETS for 10 bucks. Hoping this will fix it and not have to pay 850 for new injectors. Thanks for the response.
	Appreciate 1 feuer4285.00 Quote

03-08-2018, 03:47 AM	#7
RocketSurgeon Lieutenant 263 Rep 459 Posts Drives: 2008 135i Manual, CBR650F Join Date: Jan 2017 Location: NC iTrader: (0)	It's almost certainly MOSFETS. An injector failure is very different, one cylinder cuts out and you get injector codes. When you see 30BB or 30BA on a car made before 03/08, it's almost always MOSFETS. Fortunately it's a relatively inexpensive repair.
	Appreciate 1 feuer4285.00 Quote

03-20-2018, 10:16 AM	#9
edf8fde Private 22 Rep 72 Posts Drives: 335is manual Join Date: Dec 2016 Location: Scottsdale, AZ iTrader: (0)	Replaced all 6 mosfets. Cleared codes and car runs better than ever. It is strange, I have never felt my car run this well. Almost leads me to believe that mosfets can degrade over time. Probably just placebo though. Thanks for all of the input!
	Appreciate 0 Quote

03-20-2018, 01:11 PM	#11
edf8fde Private 22 Rep 72 Posts Drives: 335is manual Join Date: Dec 2016 Location: Scottsdale, AZ iTrader: (0)	https://www.digikey.com/products/en?...DB14N30TMCT-ND Make sure you get the FDB14N30TMCT-ND not the FDB14N30TM
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03-22-2018, 01:42 PM	#13
GEOS07335i Lieutenant 164 Rep 513 Posts Drives: 08 335i Join Date: Apr 2017 Location: Atlanta iTrader: (0) Garage List 2007 BMW 335i E93 [10.00]	Where did you take it to replace the MOSFETS? How much did it cost? __________________ 2008 335i E93, DP's, 7" FMIC, DCI,CP TIAL Q BOV, MHD Stage 2+, Alpina Flash
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03-22-2018, 02:05 PM	#14
catcher22 Captain 294 Rep 922 Posts Drives: 2008 335xi Coupe Join Date: May 2008 Location: Virginia iTrader: (2)	My DME MOSFETS blew up 2 months ago in a similar fashion. I basically have no experience with electrical engineering and didn't trust any local TV shops (the few that are left) to work on this DME, most likely for the first time, so I sent it off to: https://n54dmerepair.com It's $250 for the service, which depending on how you look at it could be a steep price or not. Remember, a new one costs upwards of $1500. Sure, the MOSFET parts are $15, but it's also very easy to destroy the DME if you don't know what you're doing or don't have the proper tools. The service was well worth it, all 6 MOSFETS were replaced, tested, and my car has been running great since I got the DME back a month ago. Basically plug back in, and play!
	Appreciate 0 Quote

03-22-2018, 02:24 PM	#15
feuer Major General 4285 Rep 9,222 Posts Drives: wife crazy! Join Date: Apr 2015 Location: Chicago, IL iTrader: (5)	$250 for repairs on MSD80 is way too much. It should be around $80 to $120 max. MSD81 upgrade runs about $400-450 for used part and programming. If you want to keep MSD80 buy Mosfets and have any TV or computer repair shop to swap them for you.
	Appreciate 0 Quote

03-14-2022, 06:43 AM	#18
lee.j.hill New Member 0 Rep 20 Posts Drives: bmw e93 Join Date: Mar 2022 Location: essex iTrader: (0)	was this thread for a msd81 I have just had 30BA cyclinders 1,2,3 and i have a msd81
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03-14-2022, 01:29 PM	#20
C4maro Private First Class 82 Rep 184 Posts Drives: 335i Join Date: Aug 2018 Location: Canada iTrader: (0)	Are mosfets something to do as preventative maintenance on a stock n54? Last edited by C4maro; 03-14-2022 at 10:36 PM..
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03-14-2022, 06:09 PM	#21
Sgop335 Colonel 668 Rep 2,074 Posts Drives: 07 335i e92, 08 535i Join Date: Jun 2014 Location: MD iTrader: (1)	One could by replacing the mosfets. My e60 stranded me. But the issue is it can be mosfets or power supply. In my case the mosfets tested fine so wouldn’t have helped __________________ 335i e92 TPC 19Ts
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03-15-2022, 02:28 PM	#22
TiAg740 New Member 2 Rep 5 Posts Drives: 2008 335i Join Date: Mar 2022 Location: 43054 iTrader: (0)	Posting to get more access to my newbie profile. 2008 e92 335i ~70,000 miles. I had a mosfet issue. My codes were similar and when it went I thought something went in the engine, fairly violent. Got replacement mosfets via digikey via YouTube video suggestion for similar pricing as above and had a local audio repair shop that I take amplifiers to replace them for $60. Less than 10k miles since replacement, still good with many WOT pulls.
	Appreciate 0 Quote