Garage Storage Organization and Garage Cabinets

puppet · **Developed misfire at WOT**

This has me puzzled. 2.2 '89 T2 engine, no fault codes. Very good mechanical condition. Boost is graingered.

Stage 5 cal ... +40's, stock FPR. Autolites 63's or Champs 9Y's gapped .025"
Taylor Sprio core wires, new cap/rotor/distributor/HEP, Blaster 3 coil, 195* t-stat, CAI (front of car), MP+ turbo w/big exhaust housing, dual stock IC's.
Coolant checked ... 5W-30 Mobil 1 .. bigger radiator and oil cooler.

Was experiencing a random misfire at 20+ psi w/Champs while tuning. Gapped them down to about .027" and worked fine till about 23psi. Decided to swap in some Autolites for a change and gapped them to .027". Worked great to 25psi. Plugs look good, no detonation. Last couple days the engine started to misfire bigtime at WOT. ... like a uzi. Disconnected the battery to reset the adaptives and thinking it would start fresh.
Pulled plugs at gapped to .025" .... still misfiring, plugs look good. Figured I'd lower the boost today to try and find the threshold for this ... 18psi still produces a random misfire. Engine has plenty of fuel, even at 25psi. This isn't a lean condition.

Not sure what to look for beyond this. Not sure if gapping the plugs down further is going to eliminate this misfire. They were fine at .027" for a couple three weeks. If they were to get gapped down more .. how much farther is practical?

I'm thinking of swapping the stock coil back in here but want to see if any of you fellas have some other ideas first.

puppet · 05-22-2006, 05:23 PM

Swapped in the stock coil and the misfire at 18psi is gone. On to 25psi.

puppet · 05-22-2006, 05:39 PM

Boy, these stock coils work great.
Next question: a lot of you guys have been living at 25psi for a while. Do you eat coils or have I just found out that da Blaster not as well built as the stocker?

DUGZSHELBY · 05-22-2006, 11:28 PM

I have burned a few coils stock and accell. They always short internally and will always pass a resistance test. They only show bad on a scope under load. I believe the enamel coating on the windings breaks down after some abuse then they start arcing under load internally. I now have the Mallory Promaster oil filled coil and have had no problems for over two years now. I also use a .5 ohm resister inline too as this coil has very low impedence ".7ohm" and may eventually burn up your smec ignition driver.

DUGZSHELBY · 05-22-2006, 11:36 PM

Forgot to add use a "recessed electrode" plug and gap .030". If you have metal spiral core wires you can also use non-resistor plugs too. I have had good luck with the NGK B9EG "which are recessed, resistorless, and small electrode diameter". NGK BR9EG is same but with resistor.

puppet · 08:36 AM

Good info DUGZSHELBY. I'll have a look at the Mallory coil. ( P/N 28720 ?)
Do you use the .5 ohm resistor to protect the smec's ignition driver?
Do you happen to know if the NGK B9EG is the same heat range as the Autolite 63 or Champs 9y? How do the recessed tipped plugs hold up?

DUGZSHELBY · 05-23-2006, 08:59 AM

Mallory Promaster #29440 "around $75 from summit racing". Yes I use the .5 ohm resistor to protect the SMEC driver. You may be able to get away without the resistor but the current flow through the driver has got to be massive without it and could probably overheat it and burn it up. Im not sure about the diff between the NGK and Autolites / champs heat range. If you could get ahold of a spark plug book at an auto parts store you should be able to cross reference between the plugs to see what you need. The recessed tipped plugs seemed to decrease the spark knock sensitivity with the swirl head I have.