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View Full Version : PLEASE HELP Ignition issue



newmexicosaint
11-03-2012, 12:52 PM
I am at a loss. Here is my situation...

I have a BBC with a FAST XFI system which includes a dual sync distributor. At about 400 miles on the new engine it has started to pop/stumble under a load in high RPM (5500-6500) and seemed to be through the exhaust. The car has a MSD 6a box and a Blaster II coil. At first it seemed to happen at high RPM and only when the car would get some time driving. After about an hour of steady driving (some heat soak) it would start to break down and pop/stumble under a heavy load and at High RPM. The engine is running around 170 degrees and almost never gets over 185. Now it will do it at lower RPM (2500-UP) regardless of engine temp. Through some data logging of the XFI my fuel is spot on and not leaning out at any point through the RPM range.

I have noticed that the popping and sputtering shows up on my tach and on the data log it is showing up as blip as going lean but for less than .5 second. I assume that is shows as this on the data log because the pop is introducing oxygen to the o2 sensor or vice versa. the blip is far to short to be a fuel issue because of the near perfect table numbers before the pop and after. I moved the white wire from the MSD box away from the coil wire (which it ran along side of it for about 24"). The coil wire is about 26" long. The wires are Taylor thunderbolt 8.2 and are new with the motor. the whole system has 475 miles on it now (engine/injection/ignition/wires). I also checked the coil for overheating after long drives and it was barely warm to the touch. Checked the wires/how they were plugged in and cap. New spark plugs and I even cleaned the terminals in the cap. To no avail...

Well, I have given all the info I have...ANY information or experience with this type of problem would greatly be appreciated. Thanks guys!!