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davecox
06-26-2007, 07:12 AM
Guys I Have A New Car And New To A Programmable Digital 7 And I Have A Problem. I Am Not Using Much Of The Features Right Now Just The Rev Limiters Mostly. I Have My Shifter Setup On The Rpm Switch. The First Time I Took The Car To The Track It Shifted Fine. When I Went Back The Car Seems To Be On A Rev Limiter Right Before It Suppose To Shift And Wont Shift. I Moved The Shift Rpm Up And Down And It Does The Same Thing. In The Pits I Can Put It Real Low About 2000 Rpm And It Will Shift. I Do Not Know If By Accident I Changed Something On One Of The Other Features To Cause This. If I Reach Over And Shift It By Hand It Runs On Out Fine.

Thanks Guys

msdtech4
06-28-2007, 02:32 PM
davecox,

Chances are you need a relay inline and the load of the shifter is more then the output of the box can handle. Install a relay inline and this will help eliminate that problem. We have run into this issue with all of the RPM switches (not just the digital box) and the relay is the fix.

Thanks,

MSD tech4

Sparky_wp
06-28-2007, 10:01 PM
The RPM switch wire already does run through a Relay.
The Shift Solenoid is the spring loaded type that needs to be energized to hold the Spring Plunger back. I provide Ignition power to the Solenoid and a Ground through the Normally Closed Circuit of a Relay.
Once the desired Shift point is reached, the RPM SW wire provides a Ground signal on the Brown/White wire which energizes the relay and breaks the Ground to the Spring Solenoid, which forces the plunger forward and shifts the shifter into high gear.

I wired this car and have successfully wired other cars in this fashion with no problems.

Michael Browne

msdtech4
06-29-2007, 08:53 AM
Michael,

That is correct as far as wiring but something is creating an excessive load causing this to happen. I would recommend trying a different relay first and second if you are not using the shift light output (yellow wire) and connect it to the ground side of the relay. This will allow you to check and see if the output is an issue. If this is a 7530T box you must launch the car on the limiter or the outputs will not be correct and inaccurate. If you use the shift light output make sure that you turn the launch light (high and low setting) up to 12000 so it is out of the way.

Thanks,

MSD tech4