[Nytalonsti]

Good evening guys,

Currently have a msd80 with bad injector mosfets, where I'm stumped is the car was running fine last night when I parked it until this morning after I replaced all ignition coils with Delphis as a preventative I started the car up and to my surprise engine was misfiring. I shut if off immediately and rechecked my work.

Restart the engine and it's still running like crap. I reinstall the old Bosch coils and now the car wont start at all it just cranks. I pull the codes for random misfires, 30ab and 30bb which is pending. I remove the DME to test the mosfets and found #1 and #4 injectors mosfets were faulty.

My question is did the Delphi coils take out the mosfets? These were new coils I had purchased some time ago for my last 335i.

Appreciate the help.

[stewbets]

I would assume they were on their way out and the new coils we're able to take a little more juice, causing the mosfets to blow. I wouldn't fault your new coils, and I wouldn't expect anymore problems once you replace the mosfets.

[Steve Sas]

Aren't the MOSFETs that fail for the fuel injectors?
What does it have to do with the ignition coils?

[euromobe93]

Did you change all mosfets or only bank 1 only or like bank 2 only

[Nytalonsti]

Originally Posted by stewbets

I would assume they were on their way out and the new coils we're able to take a little more juice, causing the mosfets to blow. I wouldn't fault your new coils, and I wouldn't expect anymore problems once you replace the mosfets.

This is what suspected, that they were just tired but I also discovered the "new" coils I installed were counterfeit Delphis I had bought them off ebay and never used them. I ordered a set from Fcp.

Originally Posted by Steve Sas

Aren't the MOSFETs that fail for the fuel injectors?
What does it have to do with the ignition coils?

I've heard of mosfets taking out the ignition coil on the cylinder with a bad mosfet so I wouldn't be shocked if it would happen the other way around.

Originally Posted by euromobe93

Did you change all mosfets or only bank 1 only or like bank 2 only

Had the defective ones replaced only because we had 2 mosfets. I just picked up an msd81 going to do the conversion soon and be done with it.