1985 firebird, carbed 350, MSD 6AL2

Following a battery relocation, and MSD install, (also had steering column removed for some unrelated wiring), my engine keeps running for a few seconds after turning off the key. It runs perfectly smooth until it finally shuts down, but seems to act like there's a delay between the key being turned and the engine shutting off.

Running a Holley 750, and doubting I have a fuel drip issue causing it to diesel. I could be wrong, but was hoping someone might have some insight.

any questions regarding equipment, just let me know.

 

Old school (not digital) 6AL2?
It sounds like you need to install the diode in the ignition circuit. The charging circuit keeps the MSD powered.
It's in the MSD tech notes. https://www.google.com/url?sa=t&rct=...eEr_NhXVta5P7U

pg 8
ENGINE RUN-ON
If your engine continues to run even when the ignition is turned Off you are experiencing engine Run-On. This usually only occurs on older vehicles with an external voltage regulator. Because the MSD receives power directly from the battery, it does not require much current to keep the unit energized. If you are experiencing run-on, it is due to a small amount of voltage going through the charging lamp indicator and feeding the small Red wire even if the key is turned off.

Early Ford and GM: To solve the Run-On problem, a Diode is supplied with the MSD in the parts bag.
By installing this Diode in-line of the wire that goes to the Charging indicator, the voltage is kept from entering the MSD. Figure 6 shows the proper installation for early Ford and GM vehicles. Note: Diodes are used to allow voltage to low only one way. Make sure the Diode is installed facing the proper direction (as shown in Figure 6).

GM: Install the Diode in-line to the wire going to terminal #4.

GM: 1973 - 1983 with Delcotron Alternators.
GM: Delcotron Alternators use an internal voltage regulator. Install the Diode in-line on the smallest wire exiting the alternator (Figure 7). It is usually a Brown wire.



Most other applications: On other applications where engine Run-On is experienced, a Resistor can be put in-line to the MSD's small Red wire (Figure 8). This resistor will keep voltage from leaking through to the MSD unit.

MSD •  WWW.MSDPERFORMANCE.COM  •  (915)  857-5200  •  FAX  (915)  857-3344

 

Now, if I could only remember where i put the msd box it came in!!

Thank you for an extremely helpful reply!

 

You're welcome. I hope this is your problem because it is an easy fix.