6500 RPM ignition problem
 

Got the car onto the dyno yesterday for some tuning . At about 6500, sometimes not until 7K 4th gear pulls. I've got a pretty bad ignition break up. I'm using an E8, LS truck coils, NGK R 10.5 plugs on E85 (although it did this with 100 octane as well). This is a 2nd gen with a stock CAS. The fuel is there. We're at a steady 11-11.3 with the AFR( a little rich to be safe for now)

Where should I start? My coils are grounded to the shock tower. I read in a post that they should be grounded to the motor. I will do that, although I'm fairly positive that's not the answer. I'm sure my tune can be looked at and gone over. I also read a little about the Split timing and a little confused about where is should be under heavy load and boost.

Please help

What other modifications do you have? What turbo? How much boost?

I'm using a COMP turbo 70 trim (I think) with a .82 hot side. We're making about 16 psi at 6500. And that's the lowest achievable. Likely due to manifold design and single synapse 50mm waste gate. I've got most of the standard stuff. Greddy Front mount intercooler. 720 primes, 2000ID secs. SX regulator, SX 1000 gal/hr pump, -8an fuel line to secondary rail. It's an S5 T2 with S4 rotors. FD upper manifold with a RotaryWork throttle body. GM coolant temp, air temp, & map sensors. I have a datalog I can email to someone later tonight from my pc if it helps. Is this enough info?

What ECU? What is trigger since last home when it breaks up?

Careful with the truck coil. They've been proven to auto discharge as a dwell limiting feature. What is your dwell setting?

It's a haltech E8. Please don't ream me, but I'm not familiar with "trigger since last home". After reading some I know now that I should have. I do not know where to find this. My tuner is a good friend of a good friend. My car is his 1st rotary, although he is a very good tuner he isn't familiar with a few things here and there.

Trigger filter is set at 1, home filter at 1, dwell mode is on constant charge at 4.5 ms. Trigger angle 65, spark break 600

Trigger since last home is a value in the trigger diagnostics. Been a while since I fooled with an E series and don't have software available in front of me to explain it. If you looks through the available values to datalog, it's probably the very last, or near last, on the list. Log it and repeat the issue. With a stock CAS, the value should be 12 at all times and never change. If it changes, you have a trigger issue, not an ignition or fuel issue.

Ok thank you. It will likely be a little while (few weeks) until I can get back into the dyno. I don't really have anywhere to stretch out 4th gear. So if I do have a trigger issue, does this mean my aging CAS is likely the cause? I did see a little rust build up inside the CAS on the wheels. Is the crank trigger kit the best resolution for that issue if it is my problem?

Not necessarily the CAS. They rarely go bad. Does it break up in 2nd or 3rd? If not and it's making more boost in 4th, it's likely an ignition issue.

I'm going to try it this weekend, and log it. I have a feeling it's one of the coils. I have a back up set of the LS truck coils although I'm thinking of going a different route after reading many posts, It's didn't do this when it was originally tuned almost 2 years ago. Also are my NGK R6527-10.5 plug gappable? If so where should they be set?