Ignition help...Andy, Mark and I stumped :), not typical problem...Link EFI |
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Ignition help...Andy, Mark and I stumped :), not typical problem...Link EFI |
Mueller |
Aug 7 2005, 07:58 PM
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#1
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914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None |
Static timed at 10°, no mechanical advace, the ECU controls spark (the ECU does not add advance from 0 rpm to 500 rpm)
Car starts up fine, once I get the revs to 2500 I get spark scatter...we cut a hole in the dizzy cap and confirmed this In the picture, the rotor turns clockwise. White marks are open windows for the trigger, red mark is the trigger....black marks on the body of the dizzy are the locations of the leads for the sparkplugs. I changed the location of the LED (red mark) and it did not seem to help at all...... Attached image(s) |
McMark |
Aug 7 2005, 08:58 PM
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#2
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914 Freak! Group: Retired Admin Posts: 20,179 Joined: 13-March 03 From: Grand Rapids, MI Member No.: 419 Region Association: None |
We really were stumped. The problem seems to be that the rotor on the Mallory distributor appears to have passed the HT Lead terminal by the time it fires. The trigger window passes only about 8 degrees before the rotor sweeps past the HT terminal. Sooooooo, unless the LINK EMS is waiting 90 degrees before firing the plug, we don't see how it can get more than 8 degrees advance without making the spark jump huge distances (read: spark scatter). We looked at Andy's MSD distributor and their "points" triggers are 45 degrees off of where the rotor points. So there's plenty of room for advance.
We spent about 1.5 hours just trying to rationalize why, even with the static timing set at 10 degrees and the ignition table zeroed, we were getting spark scatter. I'm still not confident I really understand the problem. |
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