[EndOfAnEra]

hey guys. i have a 2008 n54 i bought earlier in the year for super cheap that was all in shambles. I have spent the last few months slowly working on it and putting it all back together. I finally tried to start it yesterday for the first time and it just kept cranking without starting. The only engine-related codes were 30ba and 30bb which I know are related to fried mosfets. I am planning to get a msd81, but would those codes cause the engine not to start? Is there something else it could be?

[Dave92N54]

https://www.e90post.com/forums/showthread.php?t=1096771

I would give this a read, check these things, if no luck then replace DME.

[stewbets]

Originally Posted by EndOfAnEra

hey guys. i have a 2008 n54 i bought earlier in the year for super cheap that was all in shambles. I have spent the last few months slowly working on it and putting it all back together. I finally tried to start it yesterday for the first time and it just kept cranking without starting. The only engine-related codes were 30ba and 30bb which I know are related to fried mosfets. I am planning to get a msd81, but would those codes cause the engine not to start? Is there something else it could be?

I'd start by getting the DME out and checking the mosfets with a multimeter. It's a really easy process. I had 2 separate mosfet failures because I didn't replace them all the first time around. If both banks have a bad mosfet, the car isn't going to start.

[EndOfAnEra]

Originally Posted by stewbets

I'd start by getting the DME out and checking the mosfets with a multimeter. It's a really easy process. I had 2 separate mosfet failures because I didn't replace them all the first time around. If both banks have a bad mosfet, the car isn't going to start.

Well I am turning this car into a track car, so I will be buying a msd81 soon. The key that I wasn’t aware of is that if both banks have a bad mosfet the car won’t start. I didn’t know that. Are you 100% sure that’s true?

[stewbets]

Originally Posted by EndOfAnEra

Well I am turning this car into a track car, so I will be buying a msd81 soon. The key that I wasn’t aware of is that if both banks have a bad mosfet the car won’t start. I didn’t know that. Are you 100% sure that’s true?

In my experience, either of those codes shuts off the entire bank. Since you've got both, you've got no banks left to fire. Having both codes could also very well point to a deeper issue. Out of curiosity, what exactly about tracking a car necessitates a DME upgrade?