Weird ignition problems, I think... Options

[TonyAKAVW]

I converted to a point-less ignition module some months ago, and up until recently had no problems with the engine. A month ago or so I was driving and had the car heated up pretty well, when it started to have problems at low RPMs. The tack started going nuts, and unless I had the engine at high rpms it would stall out. This only happened when the engine got hot. My daily commute is nor more than 10 minutes each way so it wasn't really much of an issue.

So I took off the cap and things looked funny inside. The part that the rotor rubs against at the middle of te cap was worn pretty good for being only a few months old. It also looked like the rotor was striking the contacts at their tops. My thought was that the little disk with magnets for electronic ignition module was causing the rotor to stick up too high and when the car got hot, the shaft of the distributor got a little longer and passed the threshold of working. so I sanded down some of the base of the rotor and put it back in. It seemed to help a bit.

The next problem I fixed was a leaking fuel line which I caught very quickly. Ignition was still not working great however until I pulled out the rotor and wiggled it back in a little better.

Today on the way to the dentist (a bit farther than the car usually goes) another weird thing started happening. If I didn't hold the throttle open a bit the engine would idle on 1 or 2 cylinders for a few beats and then die. Occacional backfires too. So I'm still thinking its an ignition problem...
The tach would drop very quickly to 0, unless I had my foot on the pedal. Does this sound like a TPS problem maybe????

The engine runs very well except when it is allowed to die. Its not missing, etc. Just struck me as odd that it would behave the way it is.

My current plan is to get a new ignition module, maybe a pertronix, and install it to see if that helps it. Any other suggestions?

-Tony

[TonyAKAVW]

So on the way home from work today I stopped by Pep Boys and grabbed a new cap and rotor. The old one was worn and had carbon deposits all over the inside, probably because the rotor sat too high on the distributor shaft. I sanded the base of the new one down 50 mils and it made plenty of clearance on the bottom for the magnet disk.

Tonight I took the car out for a spin and 15 minutes into it, the problem came back. came to a stop light, the engine felt like it was running on 1 or 2 cylinders, the generator light flashed in unison, and the engine died and the oil light came on. Started it back up and stumbled home with a single good and loud backfire.

When I replaced some fuel lines recently I checked the vacuum lines to make sure everything was fine, so I think they are okay and all in place.

Something that struck me odd is how the problem is almost digitally heat related. Beyond some temperature the problems are there, below it they are completely non-existent and the car runs perfectly. I'm wondering now if maybe my CHT is acting funny. I suppose tomorrow I'll measure the resistance and drive a bit and measure it again. To rule out the ignition I could drive around with my oscilliscope hooked up to the coil input to verify I'm not dropping fire pulses.

How's that for EE jargon Aaron? (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

-Tony