Initial Position of Distributor Incorrect?

[sclebo05]

'81 Fuel Injection, ran great until I fiddled with it! About a month ago, I determined that my distributor's vacuum advance was not even connected and once connected wasnt functioning. Not sure if it this means it was stuck in full advance or none and the PO just disconnected it. I purchased an new distributor with the vacuum advance unit.

Installation went pretty well, lined up the crank to TDC, static timing on the cams seems OK, dropped the dizzy in and tried to line up #4 for spark. Car starts and seems to idle OK. Using what I believe to be the 10 degree BTDC mark for ignition which is the furthest from the center of the block. Revving the engine seems to advance the timing per my timing light. Took it out for a spin, and under load I get misses, crackles and bangs. This gets worse at higher RPM. Was able to make it back home despite the noticeable power loss.

Did a bunch of reading on the forums, and I have 2 newbie questions. First, does this system have a 'waste spark' meaning that there is technically a spark on #4 on both the combustion and ignition strokes? While troubleshooting I've turned the crank to line everything up, but if there is a waste spark it shouldn't matter which 'stroke' I'm on? Second, is there a correct orientation for the distributor as it is dropped into the engine? I know that the dizzy can be rotated a bit for fine tuning. I feel like this distributor is pointed more 'across' the engine bay, and the previous one more towards the driver-front. Any advice to line this up properly?

Lengthy post, thanks for the help.

[bobplyler]

No waste spark. The distributor rotates at 1/2 crankshaft speed.

One thing to check is the magnet below the pickup. It's easy to put it in upside down.

[GeorgeT]

Also check the wires under the distributor plate, it's easy for them to get frayed and cause issues at higher rpms.

[RRoller123]

The Computronics add on distributorless ignition system is a waste spark design, but not the stock distributor.

[spider2081]

If you purchased a new aftermarket distributor I have seen 2 recent failures with them. The plate that the pickup coil/magnet attaches to broke free from the center shaft housing. This lets the plate wobble inside the distributor. On the other distributor the white wire at the coil pack connector was broken inside the insulation. I think when the pin was crimped on the crimp cut the conductor. Visually the connector looked ok but with a slight pull on the white wire and the insulation pulled right out of the black molded plug with the 2 pins in it.
Have you tried the original distributor again to see if the engine runs better???

[SteinOnkel]

If you purchased a new aftermarket distributor I have seen 2 recent failures with them. The plate that the pickup coil/magnet attaches to broke free from the center shaft housing. This lets the plate wobble inside the distributor. On the other distributor the white wire at the coil pack connector was broken inside the insulation. I think when the pin was crimped on the crimp cut the conductor. Visually the connector looked ok but with a slight pull on the white wire and the insulation pulled right out of the black molded plug with the 2 pins in it.
Have you tried the original distributor again to see if the engine runs better???

This I can confirm Unfortunately, this is a not too common connector that I have not been able to source in individual parts. Re-crimping it and adding a drop or two of solder would not be hard and fix this issue permanently.

[tima01864]

Not sure if this comment will help, Disconnecting the vacuum advance hose and blocking it while timing the engine is recommended.

[sclebo05]

Everyone above posted some helpful information, thanks for that.

I ended up reverting the last few components that were layered in, the coil, ignition control module, and even the old distributor with the failed vaccuum advance. Not needed since timing is recommended without it.

Used a compression tester to make 100% sure which stroke cylinder 4 was on, and set the ignition timing on number 4. Car sputtered to life, and I rotated the distributor slightly until I got a nice even idle at TDC.

Humorously, after an absolutely perfect idle for 5-10 minutes, the car just died, and would not restart. It was comically abrupt. In my haste, I never tied down the distributor wire, and it came in contact with the exhaust manifold shield, melted, and shorted the spark. Sheesh.

Anyway, thanks for the above tips, I'm at least running again. After a few short trips, I'll try the new distributor, and if brave, the new ICM and coil.