lakeffect2

My inigtion system apparently died. I thought I had it fixed, but died again. I noticed something that seemed weird.

I have a 1993 Caprice wagon with a 400block and TPI system, 730 ECm, Prominator chip yada yada.

Heart of the ignition is an Accel 300+ with Accel Gm remote coil Harness.

Tracing voltage, Key on...
+12.8 at battery, ground to block
+12.6 going into to Accel box from key, same ground to block
-8.6, output from Accel box to coil, same ground to block

YES, Negative -8.6

Why negative, why not another +12ish reading?
Is this the nature of double strike digital boxes to have a +/- output or or is it case of WTF? I haven't clue as to what to expect or how to diagnose with digital systems.

lakeffect2

I have an update. For clarification,this is a 1993, old style dizzy with a remote HEI coil, no optispark.

Fiddled with it last night, got it to fire up. Problem solved?

This morning it started up fine, split second to turn and fire. I drive five miles to the dentist. Came out 30 minutes later, found it would not fire up again. I disconnected the Accel box entirely. I had the original coil to module wire and plugs with me, and wired it back up to stock reconfiguration. Again it cranked, but no indication of spark.

Got me wondering if the Ignition Module in the dizzy has crapped out. So it seems to start after it has cooled down for along period, like overnight, but won't show signs of spark when hot.. I have usually fiddled with something by then and it starts, so I think I have the problem solved, drive away and get towed home again when the problem returns upon restart.


Any thoughts out there?

MI ROC-Z

I'm no expert, but first I have heard that Accel stuff is poorly manufactured and MSD is what I put in my 5.7 TPI. As for the difficult starting after it has run and warmed up you might want to try drilling vent holes in your distributor. The vent holes would need to be toward the firewall of the car, about level with the rotor, and only one or two. While installing my MSD kit I actually looked at the instruction manual and it mentioned the possibility of crossfiring within the cap due to air pressure within a stock cap. Not sure if this helps but seen you hadn't received any responses yet and I know how frustrating that can be. Good luck.