Dead Cylinders on 72 280SE 4.5

[Rackne]

I lost power at the end of a fifty mile cruise with a newly installed Crane Cams ignition system,with an MSD 6AL, and an Accel Super coil. The plug gap is .050-Champions. The engine vacuum is a steady 10 lbs. at the throttle body under the throttle plate, this is the highest reading I can get adjusting the timing within the range available but it seems to desire more counterclockwise movement. Compression is at 120 lbs on all 8. The injectors seem quieter on the middle two injectors on both sides but especially so on the #2 and #3 cyl. Disconnecting the plug wires at the cap doesn't affect the idle on these two cylinders. The injectors click and spritz when hot wired, and the plug on #2 showed no sign of being exposed to the combustion process. I would apreciate any advise to get me back on the road.

If that plug doesn't look like it has been involved in the combustion cycle and the idle isn't affected when you disconnect those leads, then it sounds like it either isn't getting any fuel to ignite, which you have ruled out already, or you aren't seeing any spark. Remove the plug from the cylinder and lye it on the cam cover. Plug it in and spin the motor over and see if it fires. Good luck, sounds like a nice car.

Matt.

[Rackne]

You could spot weld with the spark after these modifications. Nice big and fat blue lightining bolts. I made a noid light (they've never heard of one at the local O'Reillys) this morning and hooked it up, no voltage to the injector. I've previously pulled, cleaned and lubed the points (no not the points themselves, the contact surfaces) any one know where the grounds for the injectors are? I've heard that they each have an individual ground and perhaps some corrosion is going on.

[Rackne]

Found the ground connections and they were grounded, cleaned them anyways. No effect, tried checking for pulses on the positive side with my noid light, found none. So it had to be the points, pulled the distributor and got out of the bitter cold to the comfort of my kitchen table. Theorized that maybe the contact surfaces had worn so much that the lobes no longer opened the points, so using my needle nose pliers I made a few adjustments to compensate for wear... and the car refused to run on any cylinders. So back in the kitchen I made more adjustments in the opposite direction... the car started and I got pulses on the noid light. Reconnected the injector and got all 8 cylinders going, set the timing and went for a cruise. So fine to be on the road again.
Thanks for your help -Edward Richardson III