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.

---
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?

Whoa. Did you leave it in gear, and hand brake on? If so, you are trying to turn the whole drive train. Otherwise, look down in the engine mount around the pulley. You might have dropped something down there.

Yes, I am an idiot. I had left the car in neutral in my garage but since I haven't driven it in months I instinctively put it in gear after driving on to my lift.

This is what happens when one is stressed out and not thinking clearly!

I discovered the issue immediately after I wrote the post and went out and cranked it over. I'm sitting here now, dizzy in hand. Thanks Pete!

Hah! Add that to the list of "dumb 911 mistakes" thread.

Following the disassembly instructions here: https://nineelevenheaven.wordpress.com/maintenance-of-the-distributor/

I am trying to remove the 3rd screw on the base of the stator. Using a brand new 3mm Bondhus Allen wrench. The first 2 came loose with a lot of pressure but the 3rd one won't come loose. I carefully seated the Allen key all the way in, used a little WD40 nd it just won't budge and the head is starting to get a little mangled. I am going to let it sit overnight with more WD40.

Does anyone have any recommendations? I could drill the head and try a screw extractor but I think I'd just buy a rebuilt dizzy from our host before mangling this one.

looshttp://forums.pelicanparts.com/uploa...1729552637.jpg

I'd keep at it. Here's a trick: Use a drift pin or something like that to hammer down on the screw head. That will help shock the frozen threads loose, and you might be able to compress the mangled part of the socket head to make it tighter on the Allen key.

Also, use a real penetrating oil, like Kroil or Liquid Wrench.

Thanks Pete, I'll give that a try. I've used that trick in the past but didn't want to bang on the dizzy!

Sculisco, yup, that is one of the sources of information I am using.

Well, I tried the drift pin idea, I also heated a sacrificial Allen key to red hot and placed that into the head several times. I also discovered that the vacuum can is not working.

So I've decided to buy a Porsche rebuilt distributor from our host since it will come in next week.

Quick update... I tried heating an Allen key. to red hot again and inserting it into the pesky screwed. This time I was able to loosen it! I was able to remove the stator and it was really gummy with a dark brown almost like tar material. And where the stuck screw was, was very corroded and rusty all the way down to the shaft. The advance mechanism seemed sticky but I was able to free it up with WD40 and brake cleaner. The vacuum pod is not working. So, I'm fine with replacing with a Porsche rebuilt distributor. It is arriving from our host tomorrow and I hope to install it and see how the car runs on Saturday. At least I should be able to set the timing now.

Wits' end
 

I'm back at it...

The new rebuilt (by Porsche) distributor came in this week, as did a replacement AAR. I verified the AAR works and installed it, I then installed the new dizzy. While I was at it I also adjusted my alternator belt as it squeals like a banshee on startup. There were 4 shims between the pulley halves so I moved on to to the outside. That did it, no more squeal.

The car started up after a crank and just a touch of gas. It idled at around 2K RPM. And this is where it all goes back to a complete mess again.

I let the car warm up so I can set the timing to 25° at 4000RPM. Either I've forgotten everything I've learned about setting timing or something is really odd. I have an Innova 5568 adjustable light (I've had it for almost 10 years).

Warmed up and idling at 2200RPM. My AFR is showing 14.7

So I set the timing light to 25° and rev up to 4K. Move the dizzy to get the Z1 mark on the pulley to align with the case mark. Fine so far. I blip the speed up to 5K and see maybe a couple of degrees of advance. Then I let off of the throttle (I am pushing the throttle pushrod on the left side of the throttle body) but the car stays idling at 3800 RPM. I don't think my throttle is sticking but I'll figure out how to check that.

Is it possible that now with a known good dizzy that the fuel mix I set before is the problem? I did notice that my AFR was showing in the high 13s at this point.

Should I leave the timing as it is and idling at 3800RPM and go back and check the fuel mixture or where should I go next?

Ok, I just went out to the garage and started it up again. Been sitting for a little over an hour, engine still warm. It started right up with no extra gas but is idling at 3800RPM.

I checked the throttle - pulled up and down. It is not snagging anywhere.

I also did the air plate lift test. Pushing up a bit and the RPMs drop, pull down a bit and the RPMs drop. This indicates that the mix is set properly.

Tried adjusting the idle screw. It only has 1 turn before it bottoms out and even closing it completely had no effect on idle speed.

Finally, I removed the oil tank cap. The engine speed dropped pretty quickly and the engine stalled.

Hopefully these tests might provide a clue? The only thing I can thing to do now is test again for air leaks with a smoke tester.

Thoughts or recommendations appreciated.

You said this was an experienced shop but did anyone move the throttle plate adjustment nut/screw mistaking it for a way to change idle? Really easy mistake to make if you are used to working on carbs.

Look for unbroken yellow paint on the screw and lock nut. If the paint is unbroken do NOT start playing with it to lower your idle.

Thanks. I will check that. Honestly, I do think he knows what he’s doing and wouldn’t muck with that. I am convinced that the root of all of this was that FV relay under the passenger seat. 3 year only CIS cars and perhaps he wasn’t thinking. Who knows. The car sat for 6+ months outside. Probably the longest time its ever been outside.

This is from the Bentley manual. I think this is the throttle plate adjustment. Looks like it would be very difficult to mess with. I’ll check it as soon as I can. Taking a break so it might be tomorrow morning.

http://forums.pelicanparts.com/uploa...1730581204.jpg

My throttle linkage doesn’t look anything like the photo. I think this is it though. No sign of paint on it that I can see. http://forums.pelicanparts.com/uploa...1730582884.jpg

This is a wider angle view. Red arrow pointing at the throttle adjust screw. Is that it?
http://forums.pelicanparts.com/uploa...1730583095.jpg

Look at the threads - it looks like there are a few clean threads exposed doesn’t it?

Yes that is the throttle stop screw. But more threads on the bottom would mean the flap is closed more than it was from the factory position. With the same idle screw position (the big one on the side) the idle would be lower. Yours is higher. I can tell you from my unfortunate experience there is no good reason to change that setting in a stock CIS street car. May want to send those pictures to your shop and ask about it.

I did send the photos to the shop. He did not adjust that.

So, a question. If fuel pressures are all in spec and CO is now close, and the dizzy is nee and working, is such a high idle due to too much air? As in there might be an Ir leak somewhere? Does the engine dying when the oil filler cap support thst?

I believe you said you did a smoke test earlier?