MSD 6A, Mopar distributor, HEI 4-pin Module

[flatbill]

I have been running the MSD 6A with a locked Mopar distributor. I have set it up as shown in the articles showing the Tuner Studio settings and the DIY instructions for the Mopar distributors. Now I am wondering if I need to use the HEI 4 pin module as shown in the MSD setup schematic. I was thinking that the Chrysler VR sensor would drive the MS through the relay board and that's the way I have it configured. It does run OK.

My question came to me when reviewing the MSD layout that shows the distributor running through the HEI module. Can I get some clearification on this? Thanks.

I also seem to not be getting an RPM sigmal right away when I am cranking the motor. The motor seems to be cranking for too long before the TS rpm shows up. Once the TS rpm starts to twitch, the motor fires. Am I right in assuming that there are not injector pulses until the RPM signal starts? Billk

[a73camaro]

In TS under Cranking Settings there is a Cranking RPM. If RPMs are below this number, MS will not "fire".

As for using a locked distributor, you will need a 7 pin HEI module to vary ignition timing.

[Matt Cramer]

You can wire the VR sensor (Mopar magnetic pickup) straight to the MS, and the MS to the MSD box - no HEI needed, either of the 4 or 7 pin variety. Try decreasing the Hold Ignition number to get it to see the RPM sooner.

[flatbill]

Thanks for the reply. Do you mean the "skip pulse" setting? Billk

[Matt Cramer]

Thanks for the reply. Do you mean the "skip pulse" setting? Billk

Yes. I was thinking of the wrong firmware.

[flatbill]

That fixed it right up. Now it fires up much faster too. I had the skip pulse set to 6 for some reason. I reset it to 1. I thought that this was a delay on when the computer started using the spark advance table after startup. Thanks, Billk

[Matt Cramer]

That fixed it right up. Now it fires up much faster too. I had the skip pulse set to 6 for some reason. I reset it to 1. I thought that this was a delay on when the computer started using the spark advance table after startup. Thanks, Billk

Close, it's a delay on when the computer starts using the spark, period.

[flatbill]

Thanks for clearing that up for me. Billk