I think I'm making progress.

Car is still hard to start (warm or cold) but just a touch of gas pedal and it starts up.

Got it running, engine still warm from earlier but I let it idle while I double checked timing (5° BTDC @ 2200 RPM) and checked the air plate lift test again - same results. So I started tweaking the CO screw.

I went slow and removed the tool and did that air plate lift test and occasionally looked at my AFR gauge. After about 1 full turn, the gauge started reading in the high 15s and the plate test still indicated lean. Several small adjustments later, another .5 to .75 turn of the CO screw, and the air plate test was good! Lift slight, and the RPMs decrease, pull down slightly and they also decrease. I then looked at the AFR and it was reading 14.7:1

But my idle speed is up around 2700RPM. I attempted to lower it with the idle adjustment (I was backed off about 1.5 turns) and even screwing it all the way in only lowered the idle speed to 2200RPM. I rechecked the timing and it hasn't change.

I then removed the oil cap again, and again the RPMs lowered. The engine didn't immediately stall but it did after a few seconds.

So, I think this is progress at least! At this point, I still have the dizzy vacuum hoses plugged, the OX sensor unplugged, and I am still seeing a 50% duty cycle (the engine has stayed warm all afternoon due to the summer-like heat and my constant working on it).

I had tested my AAR last weekend and it was working but I think I will retest just to make sure.

Given the decrease in RPMs when the oil cap is removed, that seems to confirm that there are no significant air leaks as my smoke test had shown also.

Now that I think the mixture is in the ballpark, I will do some research on high idle speed causes. Should I go ahead and reconnect the OX sensor? And the vacuum hoses to the dizzy?

I should add that the engine sounds pretty stable idling at 2200RPM and the exhaust doesn't smell lean or rich. It has that nice pleasant 911 SC fragrance.

Well, I think my AAR may be faulty. I removed it - it was still very hot from the hot engine. And as you can see there is a little opening even though it is very hot.

I will put it in the freezer to verify that it opens and then hit it with a heat gun to watch it close.

http://forums.pelicanparts.com/uploa...1729371079.jpg

Hit it with 12v instead of the heat gun. It should close completely.

Done. First in the freezer and quite cold, the gate did not open at all. Then applied 12 V and after 5 minutes the gate did not move. So I drilled out the rivets and as soon as the body halves separated, I heard a "snap" as the gate snapped all the way closed. I found 2 small 1/2 rice sized pieces of a black hard phenolic like material inside. I don't see where they came from - maybe got sucked in? But maybe they wedged the moving plate in place.

I will test with 12V to make sure the heater mechanism works.

Here is the internals of the AAR.
I measured the resistance at 27 Ω
It is a bosch 0 280 140 218

http://forums.pelicanparts.com/uploa...1729373363.jpg

confirmed that the heating element is not working - hooked up to a 12V supply in my house and verified 12V at the connector inside the housing. After 5 min, the arm did not move at all.

So what are my options? Can the heating element be rebuilt?

Something's weird. If you have 27 ohms across the heating element, it should heat up, and the arm should move. The bimetallic strip that the heating element heats may be broken.

At this point, contact or wait for Tony to jump in. He has lots of parts.

You can still drive the car, just plug the hoses to and from the AAR. You will have to keep the idle up with your foot for 30 seconds or so, but once warmed up, the AAR is closed off anyway.

Re your timing: The distributor should advance to its full advance by 4000 RPM. Then there is another step up as you get to 6000 RPM. Set the timing so that you have 25 degrees (it's marked on the pulley) at 4000, with both vacuum hoses disconnected and plugged. Then plug in the "advance" vacuum hose (points to the left side of the car). Timing should advance about 10 degrees. Then plug in the other vacuum hose (idle retard). Don't rely on setting the timing at the idle RPM. The important thing is that centrifugal advance gets to 25 by 4000, and that you get 10 degrees of vacuum advance. Wherever that puts the idle timing, just accept it.

Thanks PeteKz. I've taken the AAR apart to do some more testing.

Ah yeah, I can plug the hoses. It has been a long day today so I'll pick this up tomorrow morning. Supposed to be another beautiful warm day.

I had a feeling, as I mentioned in post 4.
Here is a pretty good Thread on the AAR.
http://forums.pelicanparts.com/porsche-911-technical-forum/200906-aar-revisited.html
I show a TSB in post 62.

Thanks Ed, I found that post and have been reading it. My AAR was more difficult to take apart since there is not a screw through the housing to hold the metallic strip in place. I drilled out the rivet and got it apart though.

That TSB is helpful.

I'm about ready to out to the garage and continue. The plan for today:

Replace fuse in rear panel that I blew yesterday.
Plug the 2 hoses that attached to the AAR.
Warm up the engine.
Set the timing to 25° at 4000 rpm
Check timing with advance vacuum hose plugged in, should see about 10°

---

Check everything over, including the CO setting and idle speed. If all looks good, reconnect idle retard hose to dizzy, reconnect OX sensor, leave DMM hooked to the test port so I can monitor duty cycle. Test drive.

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Meanwhile, I worked on refurbing the AAR this morning since it was too cold to be in the garage. I had a little lathe work to do ti fix the damage to the bimetallic strip mounting post but that was easy. I reassembled the unit and tested with a 12V bench supply. The valve closed all the way in about 4 minutes. And opened up again after voltage removed (took several minutes).
http://forums.pelicanparts.com/uploa...1729438286.jpg
I think what might have happened is - if you look at the "before photo" and now seeing how this device works, I think the bimetallic strip was pressed against the side of the housing and its movement wads restricted. Still seems odd that this would prevent the bimetallic strip from arching but it does look like it was contacting the side of the housing. I centered it when I reinstalled it.

http://forums.pelicanparts.com/uploa...1729438454.jpg

Well, I'm back to chasing my tail again. This is extremely frustrating.

Replaced the fuses (actually the top 2 were blown), plugged the hoses to the AAR with rubber stoppers, started up. Very difficult to start and I had to keep my foot on the gas. The AFR gauge was reading 10 - much too rich. Idle at 700, when trying to bring idle up with gas, it sputters so I let it run at 700-750 to let it warm up. After nearly 2 minutes, the idle started speeding up and the AFR moved to 15ish. So moving towards too lean. The only thing that changed since yesterday when it sounded pretty good at idle (although too high) is removing the AAR and plugging the hoses. After the engine was warmed up, I got out to check the engine area. I tested the stoppers and they were well seated.

So after a few minutes more of running and starting to see the temp gauge go up, I proceeded with checking the timing.

As I revved the engine to 4000 RPM the Z1 mark on the pulley did not move. I revved up and down several times to verify it. I didn't go much past 4000 RPM though. Both vacuum tubes to the dizzy are removed and plugged. The AFR stayed on the lean side as best I could tell poking my head up to look at the gauge. I did also do the air plate lift test and the RPMs drop with both lift and pulling down on the arm. So this tells me that the mixture is in the ballpark.

So now I'm not sure what's up. I did see the timing advance when I set the idle timing to 5° yesterday (although idle speed was ~2000 RPM). I'm going to take a little break, have lunch, take a deep breath, and go out and check it again.

Although I'm basically a newbie at 911 troubleshooting so I don't have anywhere near enough experience to add anything to this thread, I just want to say that you're not alone, I'm also deep into my own CIS issues right now and I feel your frustration!

Keep at it my man, you will figure this out!

Andy

I just went out to check timing again. Th engine has been sitting for about an hour and was pretty warm. This time it started like it did yesterday with just a little gas. It idled at 2200 RPM and the AFR was around 15.

After things stabilized in a few minutes, I went to check the timing and found that it had drifted a little and was 0°, not the 5° I set yesterday at 2200. The dizzy clamp screw is loose so maybe some shifting occurred. But, I still do not see any advance going from 2200 to 4000 RPM, it is locked on the 5° I set. Any ideas on what is going on and why this changed seemingly overnight?

Thanks Andy. I've owned this car since 2008 and have gone through all of this and more in the past! It took a few years to dial it in but for the last 10 years it has been nothing but a delight to drive. It always started on the first click of the ignition, and always had lots of power and was just fun to drive. Until I brought it out of storage in April - I didn't even have the car in my garage for 5 1/2 months and now that it's back, I am starting from square one chasing problems that didn't exist before.

With the AAR plugged I would expect it to be rich, as it would be getting less air than usual on cold start. Probably why you needed to press on the gas to open the throttle body for more air flow.
The timing issues are important to take care of. I've had to fix up my '73.5 and '86 distributors. The advance weights tend to gum up quite a bit, spacer washers to reduce play in the shaft, vacuum pods, etc.
This is a good thread on SC distributors.
http://forums.pelicanparts.com/porsche-911-technical-forum/333640-distributor-service-clean-lube-real-easy-without-removing-pinion-gear.html
http://forums.pelicanparts.com/uploa...1729460552.JPG

Thanks Ed.

My car has always been kept in a garage and I drive it A LOT from April to late November and even get out a few times in Dec thru March off the roads are clear and the sun is bright. This past winter was the first time I was not able to drive it from Dec to April. Then, at the shop, it was outside for 5 1/2 months with very little running I suspect. I have 196K miles on it. So maybe the dizzy is about ready for some R&R. I had removed the dizzy at 155K and checked it over. Replaced the green wire and the rest seemed fine at the time and has been ok until "now".

The motor was too hot to investigate so my wife and I went for a drive up in the MA and NH mountains to do some leaf peeping. It was therapeutic but would have been even more so in a 911 Cabriolet! Tomorrow I'll pop the top off and see what I can learn.

Is there a way to check that the advance mechanism is stuck with the distributor still in the car? Or if I remove the dizzy, without disassembling it?

The Porsche gods must be unhappy with me for some reason.

Today, I prepared my 4 post lift, which the car fits under during the driving season, pushed the car out of the garage, lowered the lift and then planned to drive it up onto the lift in preparation for removing the dizzy.

Before starting, I whacked the side of the dizzy a few times wondering if that might unfree things. The car started right up on the first crank with no extra gas required. And then idled at 2800 RPM. Very different from the situation yesterday and the only change was 1) the next day and 2) a couple of whacks on the dizzy.

Anyway, I pulled the car up on the lift. Then I pulled all 6 plugs - they were installed this summer as part of my ordeal at the shop. They all looked ok, not suety and not chalky. I then attempted to crank the engine over to get to TDC using a socket on the fan pulley. And that's where the Porsche gods decided to jump in.

I AM turning the fan clockwise and I am putting tension on the (right) side of the belt. I am getting PLENTY of traction on the crankshaft and I see the rotor rotate a few degrees counter clockwise. No matter how hard I ratchet, the motor is not turning over and when I release the ratchet, the motor springs back as observed by the rotor turning back clockwise. This is with all 6 spark plugs removed. I've never experienced this in the past and I literally just drove it 15 a few minutes before. The engine didn't even have a chance to get hot (it was a warm but not too hot to remove the plugs).

I know that my belt is a bit loose as I get a horrible screech on startup (you can hear it on the videos I posted earlier). The belt looks fine but it is probably 10 years old. But I am getting good friction when I try to turn it over.

Any idea what I should do to get it to turn it over to TDC?