Sounds good. I'll see about picking those up on the way home.

I believe this is a link to you are referring to: http://forums.pelicanparts.com/porsche-911-technical-forum/758788-cis-troubleshooting-dummies-2.html#post7989935

That is the one. I figured you'd have that thread bookmarked by now... :)

I got myself 6 baby bottles and adjusted per the instructions. The point where they start to dribble is fairly consistent across all 6 injectors. Then I did the half-turn lean to stop the dribbling on just fuel pump.

Unfortunately, this did not correct the issue. If I crank it, I can get it to do a putt----putt----putt, barely enough to sustain combustion, and even that for only a 5 or 6 putts. Yet I was getting a nice steady spray pattern from each injector.

Maybe my spark is to blame again? Or maybe there is still an air issue. I tried it with the idle set to closed, and 1, 2, and 3 turns towards open. There was no difference in behavior I could detect - just the smallest bit of putt-putt ignition for a few seconds.

Not sure what is next - I think I'll be pulling spark plugs again. I do need some copper crush washers because I have a tiny leak at the WUR fuel connection input.

Brainstorming for ideas - I'm going to try a new fuel pump relay. I've had a URO one fail on me twice. Maybe I'm getting consistent spray when I lift the sensor plate, but when the car is actually trying to fire cylinders the relay is getting less power and won't perform.

Remind me... I think I remember you switched CDI boxes with a friend? And that helped, right? Did you get a new CDI or refurbish the old one? Which CDI do you have now?

I have a rebuilt CDI box from Ingo, and no longer have my old one. It was a switch-out deal. After switching to the new one, the car started right up (but had the high idle, which led to the 2nd half of this thread).

EDIT: correcting my post based on re-reading my own history.

For the sake of avoiding confusion for myself (and others) here is the basic timeline.

First stage: http://forums.pelicanparts.com/porsche-911-technical-forum/856863-bouncing-tach-when-cold-zap-noises.html
1) In February, tach was bouncing and there were zapping noises from engine bay. Car ran fine otherwise. Light whooshing noise from engine bay at times.
2) Switched out new spark plug wires, new spark plugs, new cap and rotor. Still making zap noises.
3) Concurrently replaced green distributor pickup wire, new ignition coil, and disassembled distributor for cleaning and light refurbishing.
4) After the last steps, the car was running again and I took it on a long drive over the weekend. Success!

Second stage: This thread
5) Car died on the way home while idling at a light a few days later.
6) Tested many things, eventually swapping CDI box with a friend. Started right up, loud alternator squeal.
7) Ordered CDI swap from Ingo. Had alternator worked on by local shop which replaced and brushes and said bearings were fine. Probably high load from low battery voltage.
8) Started right up with new CDI, but with high idle. Couldn't bring idle down despite much fiddling with mixture. Card died when it got warmed up, and wouldn't run unless cool.
9) Played with mixture and idle to no success. After a few days of fiddling, it ceased to start when cold (and still didn't start when hot). This change took place without a concurrent change in idle or mixture.
10) Replaced fuel filter with no success.
11) Disassembled throttle body for cleaning and replaced throttle body vacuum hoses. No effect.
12) Removed entire CIS system. Cleaned and patched dime-sized slot hole on aluminum vacuum line. New seals on everything. New vacuum tubes to EGR. Learned a lot, but no success. Still won't start when cold.
13) Shorted fuel pump relay pins and reset mixture with baby bottles. Set to just barely not spray with pump running and sensor plate at rest. No success.

Current plan is to swap my fuel pump relay. My current red relay seemed slightly "clicky" so I had swapped it with one of the black normal ones. But that one started to show odd appearance near the contacts, and I thought the vacuum leak was totally to blame and put the red one back in. I am fairly certain I keep a backup FP relay around.

I may also check on my spark, although I need to fix the tiny fuel seep before I start sparking anything. Hopefully my local auto parts store has a copper crush washer in the right size.

I think I have everything listed... it has been a long Spring/Summer and my wife is really missing our drives. I have a pending appointment with the local classic Porsche shop experts next Monday, but I'd like to fix this myself before I pay to tow it and have them look.

Crank that idle bypass out a few more turns than you have already. There is a lot of turning for small adjustments on that screw.
With all the sealing you've done there may not be enough air getting through.

If that fails, put a pressure gauge on the fuel system and check all fuel pressures.

^^^ Agreed

Ok, I'll do more fiddling with the idle bypass adjustment.

I haven't yet found a local source for porsche-compatible fuel pressure gauges. My local parts store has gauges, but for anything that isn't domestic, they offer some rubber hoses and some hose clamps. I tried to make that work last time and had leaks before I reached the factory-specified 75 PSI. Is that worth trying again, or do you think I need to find the real thing?

Oso - Just going over the basics. Did you reset the timing after rebuilding the distributor? If so, was it static or dynamic? I am wondering if the timing is off, and if that is affecting your engine's ability to start.

I did reset the timing to 5 degrees advanced. The vacuum advance wasn't working, but that shouldn't affect the ability to idle. I drove the car over 100 miles with this setup (before stage 2 in my adventures this year).

The mechanical advance was working fine. The vacuum advance has minimal response to a vacuum on the distributor input. When I had the dizzy apart, I didn't realize that mechanism could move.

No luck on the fuel pump relay, and no luck with the idle adjustment. Still looking around for where I can source a Porsche compatible fuel pressure gauge.

Anyone know the size the little copper washers for the fuel connections to the WUR? One of mine is seeping gas under pressure.

I think I bought my fuel gauges from Amazon about 4 years ago. For all you've been through I would be happy to send you my set so you can get this sorted out.

That is very generous of you Tirwin. For better or worse, I am scheduled to bring the car into a local Porsche shop this coming Monday. They had a two week waiting line, but I was hoping to figure it out myself before then. I fear that, with the holiday, any gauges borrowed long-distance wouldn't arrive until it is already out of my hands.

I could push them out a few more days. I'll give them a call and see if I can do that, without dropping to the back of the line, but I'm not sure how likely that is.

Talked to some guys at lunch and got some ideas.

The slow putt that lasts a few putts/seconds after cranking might be due to a fault in the cold-start system. It was running at high idle for a while, but now doesn't start at all. Yet I get fuel from the injectors when I test them with baby bottles and mixture adjustment and the sensor plate.

For the sake of argument, let's say that I am not getting sufficient gas or air during cold start. This would mean the engine isn't turning over hardly at all. Consequently, hardly any air is getting pulled past the sensor plate, and thus hardly any gas is getting sent by the fuel distributor. This little bit of air and gas lets it putt a few times, but never really get going and dies out quickly.
This sort of fault could be caused by a variety of things, such as a fault in the AAV, thermotime switch, or cold start injector (I know the AAR is OK because I could see through it just fine when I had it out).
If this is the issue, then I think I could lift the sensor plate while cranking to effectively kick-start the ignition. Should be easy to test, right?

Jim Williams has a great post explaining how to test the AAV here:

http://forums.pelicanparts.com/porsche-911-technical-forum/740422-how-test-auxiliary-air-valve.html#post7345943

The AAR, AAV and decel valve all bypass air around the throttle body at various times for different purposes.

When the starter engages, it is creating the initial manifold vacuum to start the engine firing on it's own. On a cold start you want more fuel per unit of air. If the ratio is out of acceptable ranges you can't get it to fire. Usually that means:

A) too much or too little air,
B) too much or too little fuel,
C) or not enough spark to ignite the mixture

Let's start with C -- you've done a lot of work there. Get out your inductive timing light and put it on every plug wire to make sure each one is firing.

As for B, you've tested the injectors, which is good, but you need to test fuel pressures too. I'll send you my gauges so you can do that. You could also have a leaking cold start valve but I wouldn't put that at the top of the list yet.

For A, if you had something like a faulty AAV that was letting extra air get past the manifold, that could be causing a problem. Do the test in the link above. Rule out the decel valve by plugging the vac line and putting a rubber stopper over the vac line port. (There is a diaphragm in the decel valve that can rupture though.) The AAR should be open on a cold start and almost completely closed once warmed up.

If you have a Bentley, there is a test procedure in there for the TTV. There is also a 15ºC switch on the right side chain tensioner housing that you can test and another one connects into the crankcase breather vent. Procedure to test those is also in the Bentley. If you don't have it, let me know and I'll post it.

Edit: if you're not getting ENOUGH vacuum that probably points to something bad.

I've got the Bentley and nothing (yet) to do Thursday through the holiday. Good times ahead!

The AAV's function is ONLY to bypass the throttle-body and maintain an idle RPM
so the driver doesn't need to press on the accelerator pedal when cold. This replaced the fast
idle lever between the seats on the older cars. The AAV's bypass air is STILL drawn
thru the sensor plate, i.e. unless the AAR has an air leak (extremely rare), which
still maintains the same fuel mixture set by system, e.g. WUR, system pressure.
So it's VERY unlikely that the AAR is your problem!

Have you called the CDI box rebuilder for help in solving your problem?
Some of these guys are fairly knowledgeable about troubleshooting engine problems
besides just rebuilding CDIs. It not always a good idea to rely fully on forum
posts, as they can be misleading.