HEI 7 pin limit to 2000 RPM

[chiefmiller]

Hei 7 pin limit to 2000 RPM

I'm running V3 Main Board w/MS II Rev 2.29000, AMC 401 (stock except mild rv cam), Holley throttle body, Mallory HEI Dist with 7 pin Module w/timming set at 10deg BTDC.

Ok I have the engine running and have set timing to 10 Deg BTDC and have the Trigger Offset at 8.5 which allows it to match the Trigger Wizard big number to the crank shaft timing marks when 5volt is applied to pin B of the module. Module is wired as per the diagram in the GM HEI section.

Now here is the fun part, as I apply throttle slowly it only lets me reach 2000 RPM and it sounds like it's hitting a rev limiter, if I pop the trottle a few times I can get it to get a higher RPM but it sounds like it wants to come apart. If I run the module without 5volt to pin B it runs like a top, no issues at or above 2000 RPM. Also when I apply 5volts to the module I can hear a humming sound coming from the dist.

Is this a feed back issue or should I get another module.

William Miller
Northern Michigan

[Matt Cramer]

Please post a data log of the problem and a copy of your MSQ.