Well, at least it's not that one simple thing that wants to make you kick yourself for not finding it yourself. Maybe it is more involved and that's why it's taking them more time?

Was there any update regarding the new coil? I guess it didn't pan out?

I agree getting a real and comprehensive story on what all was done from the mechanic himself is probably better than talking to the "nice lady answering the phone".

Ingo

Your problem is likely the connector on the cable that goes to your CDI. Sometimes a wire or pin will back out of the connector but the rubber boot hides it. The wire is intermittent enough that swapping a CDI or coil will make it work better or not at all. A bad coil sometimes will do the same...

Hey - I was dealing with a very similar thing and solved it. Problem/solution was not something I've ever seen on this board, but as you had your distributor apart, it's possible you are dealing with this too.

Read all about it here: http://forums.pelicanparts.com/porsche-911-technical-forum/873470-83-sc-running-great-now-wont-start.html

Hope this helps.

Unfortunately/Fortunately, the plastic piece holding my vacuum advance arm was in place and in good shape when I took it apart for cleaning. But it is a good thing to be aware of!

I spoke to the mechanic briefly this evening by phone. He has it running and warming up normally. But it stutters at mid-power and won't go to red line properly. He suspects there is an issue with the fuel distributor, but it is hard to find parts. I suggested he adjust the dizzy advance, as I had a similar issue that was solved with 2 degrees additional advance (7 total). Regardless, I plan to pick up the car tomorrow while the shop continues to look around for fuel distributor parts.

If the advance change doesn't fix it, I'll have to decide if I want to take it apart myself. I'll get more details on the problems he solved when I pick it up.

Do you have access to a WideBand O2 meter? If it's a fuel issue you'd see the mixture is lean at those higher RPMs. It's always best to know exactly what the mixture is doing in the problematic RPM area.

IMHO, moving the distributor 2deg does not sound like a fix, I suspect something else is going on besides a simple 2 deg adjustment.

I visited the shop yesterday and took a look at the car. They have gone over all the mechanical aspects, and the car now starts, idles at the appropriate 1200 while cold, and warms down to about 800 as expected. So the WUR/AAR/TTV are operating as expected.

There is, however, some sort of issue with fuel delivery. At idle there is an intermittent thump noise as though a cylinder misses firing. When you apply full throttle, the engine hesitates before revving up. If you apply throttle very quickly, it will choke at low RPM for a few seconds. It runs roughly at mid or high RPM. I took it around the block for a few minutes, and it is difficult to drive. You can't pull out into traffic safely because you may not get the throttle response you need when you gun the engine.

They have tested the compression and other mechanical aspects. The mechanic thinks the fuel distributor is probably to blame, and is looking for appropriate parts. Obviously they are hard to get a hold of. I could probably nurse the car home (11 miles), but I'm not sure I want to take it off their hands yet. Doing your own fuel distributor work is quite complex due to zero tolerance for surface mating inconsistencies and so forth.

Can you summarize what exactly the shop/mechanic did to get the car from "not starting at all" to its current state. I am still puzzled.

I missed the main mechanic who did the work - these guys do a LOT of racing and he was already out for the rest of the week. I spoke to another mechanic who looked at the car with me and summarized what the original mechanic had done.

I'm eager to find out too. My rough understanding was that the mixture was way off spec. The only parts he used was putting in new spark plugs whilst investigating the spark strength. The old ones were probably fouled badly by my mixture adjustment adventures.

He just fixed what you messed up. You introduced a new problem. You never had a fuel problem. You had and still have an intermittant ignition problem. It is likely your coil, but it may be wiring between it and your CDI.

Keep in mind that reving the engine from idle into the upper RPM is very different than running under heavy load during acceleration. The later requires much more fuel and an open throttle.

If that shop supports racing older Porsche I'd assume their lead mechanics knows a thing or two about getting to the bottom of this. Maybe the little piston in the fuel distributor isn't moving freely or has some contamination in one of its slots. I could see where that creates wrong mixture at certain load levels.

Keep us posted on progress

This is most definitely an odd one. I find it hard to believe that these guys are having such a hard time diagnosing the problem. May just be cheaper and faster to fly Ingo into Wisconsin to get it fixed, LOL.

The cost hasn't gotten very high yet (I asked the mechanic when I talked on the phone). The revving issue was apparent with no load and exacerbated with load. I wish I had taken a short video when I was out there. They guy assigned to it is out for the weekend at a race - maybe more info Monday or Tuesday.

I'll report as more info comes to me!

EDIT: I replaced the coil this Spring in episode 1. They also tried a new coil and determined it wasn't the issue (and haven't charged me for it as far as I know).

Since you stated up-thread that your shop thought that it was ignition related,
you probably should consider borrowing your friends CDI again now that the
shop appears to have the engine somewhat back to normal, i.e. to at least to eliminate
the other key element in the ignition system.

A quick update for those following the story: I'm getting a loaner rebuilt fuel distributor and we'll see if that fixes the issue. If all goes as planned, we'll know by some time mid next week.

OMG, we know the pain you are going thru Brother!

We are all rootin for yeah! May the Porsche Gods be with you!

Jim

Dropped the rebuilt fuel distributor off at the shop this morning. I'm hoping to hear back soon.

The fuel distributor was not at fault. Rather, the new coil I bought (at the end of episode 1 earlier this spring) had failed, and was not producing a consistent spark at higher RPMs. Replaced with a genuine Bosch coil, and she's been running great.

So the problems and solutions I had in my episode 2:
a) Wouldn't start at all. Replaced CDI box and it started, but didn't idle properly.
b) After many false efforts, total CIS clean without success. Much mixture adjustment without success.
c) Mixture adjustment by a shop, and new Bosch coil fixed the issue.

Had a nice 4 hour drive with the wife today - boy is it good to be back on the road!

Just send an email requesting a refund for the failed coil. They have a replacement warranty, but seeing as the shop put in a new Bosch coil, I don't have much use for a replacement non-Bosch. We'll see what we see...

sonofagun - the coil went? I'd be prone to use it for target practice at this point.
More power to you for hanging in there - I was rooting for you from the stands. Congrats to you!