Strange timing question
 

69 2.0
Car started missing at lower (1800-2200) RPMs. Thought I might be having a fuel problem, so I changed the fuel filter. It was dirty, couldn't blow through it without considerable resistance. Cleaned everything up, but had a hard time starting when cold. Pulled the plugs and they were black and sooty. Changed them out and went to check the timing. Timing at Z1. Advanced the timing and it starts right up and runs good. Problem is, it appears to be timed at about 30 BTDC. At idle, not 6K RPM. When I back it down close to Z1 it dies rather quickly. Is it possible that the crank key sheared and the pulley slipped? Has anyone ever seen that? I'm kind of at a loss, although I do have to remove the pulley to replace the seal.
Thanks for ideas....

Bump

Have you had the distributor out? Could be it's "off" by a tooth or two.

Jerry M
'78 SC

That's what's odd. I didn't pull the distributor, because it feels like the weight springs are ok. I can get it to run good, but it 'appears' as if the timing is too far advanced, hence my question about shearing the crank key. It's just weird it was running great and then......doo doo....

I have that extra distributor in a box. I have no idea if its any good but your welcome to try it.

Thanks Mark, I hope it doesn't come to that yet....
Didn't get a chance to really dig into it. My wife was going to run to the store tonight and started her Miata. I heard a THUMP, THUMP, WHACK! and had her shut it down. I've been cleaning bunny rabbit out of her engine compartment all night.....:mad:

Just in case anyone searches for timing problems, turns out the problem wasn't polishing my fuchs, keeping the cat off of my car, buying a steering wheel, K&Ns or anything to do with ricers.....

Intermittent ignition coil. Changed to MSD epoxy-potted e-coil. Now the car starts with a turn of the key again.