View Full Version : 8973 problem

Brian B
07-28-2007, 08:26 PM
Ok we have tried to start our new motor, blown alc., promag 44, 8973 retard box, crank trigger. Motor will start on mag alone without crank trigger and 8973. Hook up the box and crank trigger, nothing. Monitor hooked to 8973 says no trigger signal, wether hooked to crank trigger or mag, but rpm still shows in monitor. Any ideas

08-01-2007, 04:13 PM
Brian B,

On the shielded cable between the mag and 8973 make sure that the ground wire is on the side of the 8973. If that is plugged in backwards you will see this happen. Also make sure under start retard that is set to zero.


MSD tech4

08-08-2007, 02:35 PM
Hi Brian,

We had something similar, although we did see a good trigger. With my laptop connected I could read the speed, but it would not fire. This was probably due to low starting rpm, so if you get it to read the tach and it still doesn't fire, then check the cranking rpm. You're looking for 250 rpm. We now start it with the mag only (190 rpm) and have a switch to flick it over to crank trigger and 8973 once the motor is running.


08-15-2007, 10:28 AM

That is a good point.


MSD tech4