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

Posted: Sun Oct 17, 2010 5:09 am
by 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

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

Posted: Sun Oct 17, 2010 5:50 am
by 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.

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

Posted: Mon Oct 18, 2010 4:36 am
by 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.

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

Posted: Mon Oct 18, 2010 5:37 am
by flatbill
Thanks for the reply. Do you mean the "skip pulse" setting? Billk

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

Posted: Mon Oct 18, 2010 10:28 am
by Matt Cramer
flatbill wrote:Thanks for the reply. Do you mean the "skip pulse" setting? Billk
Yes. I was thinking of the wrong firmware.

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

Posted: Mon Oct 18, 2010 4:18 pm
by 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

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

Posted: Tue Oct 19, 2010 4:49 am
by Matt Cramer
flatbill wrote: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. :)

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

Posted: Tue Oct 19, 2010 4:11 pm
by flatbill
Thanks for clearing that up for me. Billk