kangal63

After putting big turbos and true turbo Pipes in my E63 and starting it, it makes misfire failure. New plugs installed and ignition coils are also okey
No failure with MB Diagnostic and the values of camshaft chain timing is also ok
What could Be the failure?

kponti

Spark plug gaps might be an issue

PeterUbers

Also check all wires to the electrical ignition system in the engine... One may be loose at the cylinders in question

How often are you having misfires and which cylinders

shardul

iTrader: (1)

Is the misfire on all cylinders?

kangal63

Bought new OEM Plugs, installed them and Tested also again with the old ones, misfire again

kangal63

How I can check at which cylinder the misfires are, because no failures with mb Diagnostic System
The misfires are always at any time

KLR CLS

Do the misfires happen under load/ boost? Or at any time ie idle or part throttle? If using stock plugs gap them lower. Stock gap is at .032 needs to be closer to .022.

kangal63

The misfires are always but when I drive its more

But why lowering the gap? Before I had the turbo upgrade i had ecu and catless and there was no Problems??

Davidkuo0330

Sorry to hear that. From what I understand, the Biturbo E63 mostly have misfire either because it's tuned or the spark plugs are dirty.

I just got a full B service and purchased new Weistec plug during the service and a member advised to gap it at .022 which I had my dealer do and I even took photos of the gapping at .022. I don't want to say my car runs stronger with just the spark plug change, but it definitely ran strong with a full service including transmission and LSD change.

What kind of misfire codes are display when it happened and which tuner you went with for your turbo upgrade? I would check with your tuner first to see what is going on. More experienced tuners go through the development process seeing misfire and might be able to pinpoint it better.

Good luck.

KLR CLS

If it's misfiring not under load, then probably not spark blow out? Is it throwing codes for which cylinders? What exactly are you experiencing? Can you log boost or timing? Bigger turbos will certainly need colder plugs gapped to .022 ish to run right under load, but even stock plugs should work idle and part throttle.

KLR CLS

Another thing would be to ensure all chassis grounds are secure. Since I'm sure your mechanic dropped the motor to install the turbos maybe not all grounds were secured correctly. Ignition system requires solid grounds to fire correctly. O2 sensors could be impacted too. Ive had an issue with my cts v once with a head ground that was slightly loose and caused all kinds of problems with the car. Couple turns on the bolt, problem solved.