Hi guys

Firslty, this is not another "I have ignition break-up on stock ignition - what do I do"

I am experiencing a slight "miss" at 6500 rpm which is not related to load or boost

My initial setup was as follows:

B18
84 x 89mm
9:1 CR
B16 Head
Xenocron chipped ECU
eCtune
Stock leads
Stock Ignition
Holset Super HX40 turbo

I experienced spark break down @ 6500rpm with this setup at anything over 20 psi boost. I then established that my plug gap was too big but decided to upgrade the ign system in view of running Ethanol

New Setup

MSD Digital 6 Plus
MSD Cap
MSD Blaster HVC coil (Big blue one)
Magnecor leads

>> The car still has the 6500rpm "miss" and we checked the spark and there is a big blue spark. It is also unrelated to load as it does it at part and full throttle.

Swapped caps, leads, rotor, plugs - with no improvement

I am totally lost and frustrated with this now !!

Any ideas - can this be related to dwell in the ECU ??

 

My guess would be a bent shaft ever so slightly in the dizzy, or an old/tired pickup in the dizzy.

Try changing the whole distributor. Generally when you see an "issue" at one particular RPM point or range, its a resonance or oscillation that is created by rotational harmonics, and there is really nothing you can try except swapping out the dizzy.

 

I would imagine that a faulty ignitor could be causing this issue also... Not 100% sure though.

I like the idea of a resonance in the cam/crank pickups, too. Either way, I would try another distributor.

 

try close the gap in your spark plugs

 

It turned out to be the module (ignitor). I had it tested whilst heating it up with a heat gun and as it gets hot it starts acting up.

Changed to a different distributor and problem was solved, installed a new ignitor in my external coil/MSD converted distributor and no more problems either

Thanx for the input