[335iOnATuesday]

So I just did a huge list of maintenence to my car. ..

1. Water Pump
2. Starter
3. Oil change etc
4. spark plugs
5. All new coils
6. Headlight bulbs
7. Repaired fried DME mosfets
+ transmission fluid change

My mechanic who robbed me blind charged me just under 3 grand for number #3-7

#7 happened right after installing the jb4, last night after i got it back I did a slightly hard pull and it was excellent huge difference. Went to do another after and my ses light came on and rough idle, restarted the car... problem went away. Is the jb4 adapting or what was that ??

I'm just afraid having this jb4 on my car is going to really ruin some stuff for me but I'm also a bit paranoid so I'm looking for an outside opinion.

07 335i sedan

[wiskerbisskit]

All the jb4 does is piggyback off your dme, it doesnt change or "tune" or dme persay. Wow, 3 grand for plugs, coils, bulbs and repairing the Dme? If you would have to replace the Dme I could understand but what exactly did he do to it? Sounds like it still might be messing up. You might be driving on borrowed time.

[stanlalee]

Call me suspicious but 07's and fried Mosfets has scared me away from piggybacks. Again maybe just paranoia but I'm seeing very unofficial and unfounded correlation between the variables. I'm sure on cars its not going to happen to its not going to happen to but on cars susceptible I don't think piggybacks are helping even if its the install or an iffy connection somewhere.

[335iOnATuesday]

I had an auto electrician repair the DME.

He just stuck it in the car, my mechanic just royally screwed me. So, if my engine did that again, I should probably unplug my jb4 and play it safe ?

[335iOnATuesday]

I had the same codes but misfires 1,2,3 instead of 4,5,6 as the guy who created the fried mosfet dme repair thread, that and new coils fixed my problem my mechanic said 1 2 3 were fried so I replaced all 6.

[dbworld4k]

$3k?!?! Jesus Christ almighty. That is INSANE. That should've been a $500-$700 job at MOST.

How on earth did you agree to pay that much?! I'd have expected a few nights with his wife added in to that service - or at least injectors and new valve cover.

I'm stunned.

[glachhman]

I offer cheap repair service for the DME if anyone ends up needing it! I would keep the jb4 though, I repaired my DME and haven't had an issue for over a yr, still running jb with backend.

[335iOnATuesday]

Originally Posted by glachhman

I offer cheap repair service for the DME if anyone ends up needing it! I would keep the jb4 though, I repaired my DME and haven't had an issue for over a yr, still running jb with backend.

Any guess why I would have my ses light come on, rough idle low power after going hard? than restarting the car clear the issue? Is the jb4 just adapting or?

[Supra2k6]

You should've check for codes before clearing it

[cmotzner]

I would look at your coils i have had brand new ones fail. Run it again,get it to throw a code move that coil and see if the misfire follows.

[335iOnATuesday]

Originally Posted by cmotzner

I would look at your coils i have had brand new ones fail. Run it again,get it to throw a code move that coil and see if the misfire follows.

I checked the codes, I got misfire 1, 3.

I have all new coils, and spark plugs - which is it more likely to be? or should I just replace injectors now? () lol, i'm a huge newbie to this stuff trying to learn though.

[BRD1234]

Pull codes,
Do you have the USB for the JB4?
That would be helpful.
After you do that we could help better accuracy, anyone that says anything is purely guessing as there are tons of possible issues with these cars.

[mike@x-ph.com]

i have a 2007 with 106k miles .
I did all the maintenance you have mentioned and some (except the DME thing)
I have had the Jb4 installed for a loooonngggg time
As long as it is installed correctly and you are using one of the suggested maps, you should have no problems.

[BQTuning]

Get yourself a COBB AP, I am literally down the street from you so I can custom tune it for you right out on 441

[musc]

Yeah 3k is highway robbery. The fried Mosfets are common on 07s and some early 08s (usually with 07 build dates). It has nothing to do with the JB4. 3 of my friends had the issue and they were all running different tunes (Cobb, OFT Stage 1 and JB4). BMW had a SIB out for the Mosfets so it's common even on a stock car. The Mosfets themselves are inexpensive and my friends paid a local TV repair guy to fix them for $20. There is a DIY on this forum floating around that explains how to identify the mosfet and do it yourself.

[335iOnATuesday]

Originally Posted by musc

Yeah 3k is highway robbery. The fried Mosfets are common on 07s and some early 08s (usually with 07 build dates). It has nothing to do with the JB4. 3 of my friends had the issue and they were all running different tunes (Cobb, OFT Stage 1 and JB4). BMW had a SIB out for the Mosfets so it's common even on a stock car. The Mosfets themselves are inexpensive and my friends paid a local TV repair guy to fix them for $20. There is a DIY on this forum floating around that explains how to identify the mosfet and do it yourself.

The mosfet cost 150 to repair through an auto electrician and my (ex) mechanic tacked 50 on top of that as well as 2 hours of labor at 100 per hour just to change coils. I really wanted to tackle the guy at the shop but I just had to get out of there.

Now I'm having codes showing misfire 1 and 3, is it possible the dme shorting out fried my new spark plugs ?? I would prefer not needing to replace my injectors.... no new codes thrown yet I'll need to go hard once I'm close to home..

[CharleyGFX]

Originally Posted by mike@x-ph.com

i have a 2007 with 106k miles .
I did all the maintenance you have mentioned and some (except the DME thing)
I have had the Jb4 installed for a loooonngggg time
As long as it is installed correctly and you are using one of the suggested maps, you should have no problems.

I have a 2007 with 131k miles, JB4 since 80k miles..
Car has had some up and downs, everything care for from the 100k CPO but after 31k miles out of warranty and driven from Florida to California. Like the post above said, if you did everything right? it should be just fine.

[Jeff@TopGearSolutions]

Originally Posted by Boca335i

The mosfet cost 150 to repair through an auto electrician and my (ex) mechanic tacked 50 on top of that as well as 2 hours of labor at 100 per hour just to change coils. I really wanted to tackle the guy at the shop but I just had to get out of there.

Now I'm having codes showing misfire 1 and 3, is it possible the dme shorting out fried my new spark plugs ?? I would prefer not needing to replace my injectors.... no new codes thrown yet I'll need to go hard once I'm close to home..

At this point you need to start back at square one with the misfires.

First step is to check the spark plugs condition. Pull them all and see how the look and if they are fouled with fuel.

Then get a gap tool and ensure they are at the correct gap @ .028".

If you are still misfiring on 1 and 3 after you ruled out the spark plugs then you need move the coilpacks from 1 to 2 and 3 to 4.

If the misfire moves then you know it's the coilpack, if not then it may be an injector issue.

An injector issue would also be shown on the spark plugs if those specific cylinders are fouled with fuel on the spark plugs.

Diagnosis is fairly easy but you need to start from the beginning and troubleshoot accordingly.

Following my steps in that order you will diagnose the potential issue of if it's the spark plugs, coil or injector.

If none of this works then we need to start digging deeper. I'd also venture to say with the amount of money you paid that mechanic he should really do the right thing and help you diagnose this for free.

[335iOnATuesday]

I haven't gotten anymore SES lights or codes again which is weird. I'm going to go out and purchase some tools this weekend so I can do this stuff on my own instead of getting eaten alive at the mechanic. Really amazing to have this community full of information.

[Jeff@TopGearSolutions]

If you want to pull your plugs this car requires a special tool, available from and Burger tuning dealer, including us.

You may be able to source it locally but it might be considerably more expensive.

[musc]

I know you had new coils put in but was that before or after the Mosfets died? When the Mosfet pops it takes out the coil with it so if your Mosfet situation happened afterwards then replace the coils, even if you just put new ones in prior to the Mosfet issues.

As Jeff said, the BMS spark plug tool is nice. Has a good magnet to hold the sparkplug in when pulling it out.

[335iOnATuesday]

Originally Posted by musc

I know you had new coils put in but was that before or after the Mosfets died? When the Mosfet pops it takes out the coil with it so if your Mosfet situation happened afterwards then replace the coils, even if you just put new ones in prior to the Mosfet issues.

As Jeff said, the BMS spark plug tool is nice. Has a good magnet to hold the sparkplug in when pulling it out.

The sparkplugs were previous to the DME incident, though the coils were after the DME was repaired.

And I'm going to need to order the tool asap!