Bracket Talk
Strange Graph

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September 03, 2018, 06:51 AM
bradsc1954
Strange Graph
This weekend the moons and stars lined up so I could go racing. One my last 2 passes yesterday I got a couple of blips in the engine RPM graph that has me concerned. The first time it was early in the pass and the second was late in the pass.
What also concerns me is that when the car is car is idling. It sounds like every now and then the ignition cuts out really quick. Almost unnoticeable.


This a Big Block Ford dragster with a MSD grid ignition. Your thought and help are appreciated.


Thanks
September 03, 2018, 12:00 PM
markemark
In you .dqi data acquisition ReView of the run open the RPM, Launch, Ignition IN and Ignition OUT channels of the run. Zero the run to Launch.

Place one of the cursors on the rpm blip and then expand the display to Maximum to see if the Ignition IN signal is interrupted or missing. The cursor position will aid in finding this location faster.

If you send me your .dqi file of the run I will give you my opinion of what might possibly be causing this.
September 03, 2018, 01:13 PM
bradsc1954
Thanks . Once I get the file downloaded, I will forward it to you to look at.
September 03, 2018, 10:07 PM
62Galaxie
Some coils need to be grounded. In fact, they come with a ground strap. Also, they should be be fastened tight with rubber pads. A friend just went thru this with his rail. Dist. cap was pretty bad also.
September 04, 2018, 11:57 AM
TOP38
Brad, do u have a racepack?

If you do, a spike up in the rpm graph is noise and down is loss of signal.

If you have an ignition issue,, if your pickup is older, change it.... the go from there