I've been searching the forums and found that carbon buildup on our 37's is common and I want to clean mine. I found several threads with DIY instructions but there doesnt seem to be a consensus on whether to open the butterfly when cleaning or not.

What is the correct procedure? Should you open or leave it closed? I know not to disconnect the electrical connectors. Should the battery be disconnected however? I dont want to have an issue with a CEL or high idle as some others have had.

 

Seems to me disconnecting the battery would have the same effect as disconnecting the electrical connectors, no..?

 

Open butterfly. Do not disconnect any electrical connectors.

 

Wont opening the butterfly's lead to a high idle and the need to do a throttle relearn?

 

Nope. That should only happen if you disconnect the electrical harness during the process.

 

Just did it this weekend, opened the butterfly's to clean them thoroughly. Just be gentle when moving them as they are connected to an electric motor.

When you first start the car up it will go through an automatic relearn process and the revs will bounce up and down for about a minute (try not to panic). Once that's done the idle will settle back down to normal.
Trust me, its worth it. The increased throttle response and smooth idle is worth it. I have about 50k on my 08 and the inside of the throttle bodies and plenum was caked!

 

just got a warning yesterday, start and then engine stop. please advise

 

Not sure what you mean. Warning? Please elaborate so we can help.

 

never mind the "warning", yesterday after I picked my girlfriend from her home, when I started the car then immediately the car stalled, then I try to start it and then it back to normal. please advise

 

I also did mine last weekend I didn't disconnect anything and restart the car was fine.
Only thing I saw us looked like someone tried to removed the passenger side one already an stripped two of the hex screws, I could only remove the drivers one I had to clean the passengers while still on the intake, Plus had to take the intake off as I was changing my plugs also :/

 

I came very close to stripping the bottom hex screws on the throttle bodies. Definitely helps to use a 3/8 hex bit on a ratchet instead of an allen key like the DIY says to get more leverage.

 

seems like premature build up is extremely common in g37 TBs. Mine started stalling literally days after I purchased it.
You can move around the butterfly valve in order to clean it, just need to be careful as to not pull any wires. some of the screws are hard to get to, specially if you have an aftermarket intake but patience is the key.

I would also recomend cleaning the MAFS at the same time and even swap out/cleaning your intake filter if you have the time. I did all three along with an oil change and it ran even better than when I bought it.

 

I did the outside of mines when I put on my gen3 intakes but when I put on my z1 UIM I'll give them a thorough cleaning. I have to reset the computer anyway and take them off so unplugging them won't bother me. The idle drop can be ridiculous though.