[snsn]

I've been running with the JB+ since Feb.
I had a JB1 for a year prior, with no problems.

Today, the engine started and had a rough idle.
The half engine light came on and then "Service Engine Soon" light.
So I removed the JB+.

It's a 335i '08 - original softwear version, build Oct '07, delivered Jan '08.
No soft wear upgrades were done, on my first service, in March.
Just did an oil change.

I'm running the JB+ at 3/4. Gas is always 91 or 93 octane.

Went to auto zone and had it read, it said " misfire cylinder 3 "
Had it cleared and after the engine was shut down, the light came back on.

It is running fine, not in any limp mode.

I do not have access to a BT cable.
I've been looking for one in Northern NJ, but no luck yet.

What do you recommend I do before bring it in to BMW?
What are the odds of a code showing up?

Thanks .

[Mike@N54Tuning.com]

Misfire codes can stem from a number of causes. Common causes are plugs, fuel injectors, coils, and too low of an octane for your boost levels. Based on what you've said there is no reason to take the car to the dealer. Try to get the code to appear again. If it is the same cylinder, it is likely a dealer issue. If it is a different cylinder it is more likely a fuel issue. If you have more than 15k miles on the car changing plugs isn't a bad idea either.

Mike

[Patrys@BimmerTech]

I don't think your misfire is caused by too low octane fuel.
This type of misfire mostly happens at WOT and does not bring CEL.
If the ECU throwed CEL it means it has logged a significant number of misfires.
In your case it happened after you started the engine so I would assume it might have something to do with injectors, plugs or coils as Mike mentioned.
Just my 2 cents.

[Drakos]

All I can say is "BT Scan Tool". Anyone running a tune should invest in one imho.

[snsn]

Thanks,
I had the reading done twice at Auto Zone and the light was cleared.
Both time it was a "misfire in cylinder 3"

As I said above, after driving and shutting down, when I restarted
the " service engine soon" light was on again.

This morning, when the car is cold, it idles very rough and the 1/2 lighted symbol of an engine comes on.
After it warms up, I get the " service engine soon" light again.

But MY QUESTION, is do you think I need to have any codes cleared with a BT Cable, if in fact there are any codes, BEFORE I bring it to BMW to check it out?

[Mike@N54Tuning.com]

Originally Posted by snsn

Thanks,
I had the reading done twice at Auto Zone and the light was cleared.
Both time it was a "misfire in cylinder 3"

As I said above, after driving and shutting down, when I restarted
the " service engine soon" light was on again.

This morning, when the car is cold, it idles very rough and the 1/2 lighted symbol of an engine comes on.
After it warms up, I get the " service engine soon" light again.

But MY QUESTION, is do you think I need to have any codes cleared with a BT Cable, if in fact there are any codes, BEFORE I bring it to BMW to check it out?

Since you have been running the JB+ at higher than the default setting, it would make sense to get a BT scan before going in.

Mike

[Driver72]

Yes, have it scanned before taking it in.
If you run 91 Octane, JB+ should be at default (50%) setting.

If it's a misfire on the same cylinder I'd guess faulty plug or faulty fuel injector.

A dealer service is required.

[skate_E92]

my service engine light came on recently at about 4,000 miles (car is stock) service manager asked if i had driven the car past 10 miles left in the gas tank, wich i had, and said that can cause a piston to misfire which made the service engine light turn on... it took about an hour to get the car back and its been fine since. so now i just make sure to fill up before the 10 mile warning!!

[daniel3ooo]

get the BT tool...I mean for $300 you can save yourself from the possibility of getting your warranty denied...plus like many have mentioned in other threads you can split the cost with other n54 tuners since you the tool works for 3 vins

[snsn]

I've been looking for someone who has the professional version, in my area.
but no luck....any thoughts on who has it in NY/NJ?

[daniel3ooo]

Why dont you just buy the enthusiast version and sell it afterwards? It's only $300...and you can probably get $200 of so if you sell it after you use it

[rocketpop]

I am having the same issue with misfires, I got them before I had JB+ installed, while the JB+ was installed, and even after codes were cleared and the JB_ removed. Its in the shop as we speak with misfires.

[snsn]

I had the BT scan:
There were no hidden codes showing a tuner.
It showed a O2 sensor which was sticking.
Dealer repaired.

JB+ is back in

[Mike@N54Tuning.com]

Originally Posted by snsn

I had the BT scan:
There were no hidden codes showing a tuner.
It showed a O2 sensor which was sticking.
Dealer repaired.

JB+ is back in

Very good news! With something mild like the JB+ its rare a check engine light or code is actually caused by the JB+. Just need to check that code and let the dealer take care of it for you.

Mike

[David 12]

o2 sensor, interesting. I wouldn't think that would cause a misfire, but I could be wrong.

Are you using octane booster?

[snsn]

Yes, it was also reading a misfire in one cylinder.
Always used 91 or 93 grade.