There is an atmospheric line off the top of the WUR as mentioned. There is no vac line off the bottom, as this is for WOT enrichment in pre 80 cars. The O2 sensor system controls this function from 80 on.

the funny thing here is that the OG WUR has the same part # (bosch) as the one that I bought from a fellow pelican, however the one I bought has a nipple ,for vacuum I assume there is just an issue with bosch?. here is a pic of the OG one.

http://forums.pelicanparts.com/uploa...1207356439.jpg

thanks
Chris

Saturday morning coffee, thoughts on this one?

Chris,

If your CIS is working properly, you should stop guessing and start reading the FV duty cycle. The duty cycle is a proxy for the mixture, it will allow you to accurately make adjustments and verify that the system is working to spec. You need to hook up an analog dwell meter to the green/white stripe wire in the test plug under the plastic cover. An 80SC should read a steady 75 dwell on the 4 cyl scale at cold idle, open loop. After a few minutes, the system should go closed loop and fluctuate between 40-55 dwell. After you know the system is working, set the ignition timing to 5-7 BTDC (vac dis), the idle to 950, and the dwell to 30-40 hot. You do not want to set the timing to 0, max advance will be limited to 20 BTDC and it will run like a dog. Leave the vac retard disconnected and plugged. If you still have a hunting idle, start looking for vacuum leaks with a propane torch. The injector seals and sleeves are the first place to look.

Worked on the car all day today. my notes are as follows.

Idles great at 1050-1100 RPM as soon as I turn the screw to get it back down it starts to hunt. Car runs great on the highway and around town- no issues with accel decel, A little poping coming from it however during non load travel-ie straight flat and in 3rd.

I removed the AAR altogether to check it, I put it in the freezer for a few hours and the orifice was open more than it had been it but not all the way open. I then heated it up and it moved back a little bit but not closed. So I decided I would make my own AAR. I went to my Vanagon parts car/van and pulled the heater control flap (for the coolant) this happens to be the same size orifice and hose fittings, I put that where the AAR goes and had my own adjustable AAR. so assuming the car is hot (it was) I closed it, this made absolutely no difference in the hunting problem. But now I have an AAR that works manually until I can get a new or service the one I have.
_Injectors I put the injectors into a tester/Nozzlerator, it tests them for opening pressure and cleans them as well. I did this way back when I first started the rebuild, but I had second guessed my self today. I found that 4 of them had less than adequate spray patterns and did not have as good a flow pattern as the other 2 (I determined that they must be the right pattern), maybe they are a problem and cause of the popping??

_Lamda Control, I, just for grins, unplugged the Lambda control box under the seat and it dropped the idle to 900 RPM and seemed to run a little better but when I tried to drop the idle to 850 it started hunting again ARRRRGGG!!!!!

At this point I grabbed a Cold Beer!!!

And here I am on # 3.

Still need to test pressures but that wont be untill next Wednesday. In the meantime I hope someone can help me diagnose this issue, and my Bentley will show up.

A footnote as well. the car DID NOT do this when I bought it. I promptly removed the motor to re-build (broken headstuds) it so I never really knew if it had any issues.A PPI was done on the car but it all checked out at the time. Maybe the backdateing and cams are screwing this up??

Psalt, I will try this as soon as I get back to the car on wed.

regards
Chris

Sounds like you know your way around cars, so please don't be insulted by this:

Have you been using both adjustment screws to try to get your idle and mixture correct? I'm not clear from your posts.

I tried to get you the 2 illustrations yesterday but the site seemed to be having problems. One shows the nipple connection you asked about. The other doesn't.


Have you checked your fuel and control pressures? How about your CO?

http://www.pelicanparts.com/911/911_Parts/1978-83/1-7-2.JPG

http://www.pelicanparts.com/911/911_Parts/1978-83/1-7-3.JPG

Sorry, can't get the 2 cuts to paste correctly.

I know my way around cars pretty well, its CIS 911s that throw me for a loop. SOmetimes I am lazy and get frustrated.

Anyhow, I have not yet Checked pressures. I have been fooling around with this forever and I dont seem to get anywhere. I will check pressures on wednesday.

I see the right configuaration in your link (without vacuum) do you think that the WUR that I have is good for both applications or it is plain wrong, they have the same part#s!!!? I used the vac retard line to hook to it but dunno if that will do anything.

Also do you have any thoughts on why this is doing this now and was not b4 the rebuild? is it possible that I connected something incorrectly? I cant see behind the airbox well enough, but it might be simple, right?

thanks again
Chris

So, what's the Bosch number on the WUR?

http://specialtauto.com/images/warmup-072.jpg

This is for an 80 SC. Have you been fooling w/ both the mixture and idle adj screws?

This second one is for an 81-83

http://specialtauto.com/images/warmup-090-new.jpg

Both that I have are 72's like I said they have the exact same numbers but the OG doesnt have the vac line nipple (see picture). In the pic you can barely make out the "72" that is stamped at the end of the #.

Chris

The 072 nipple..
 

The early 072 WUR didn't have a nipple at all. Later 072 WURs had one. The nipple is simply for an atmospheric vent to the WUR interior. The ones without a nipple on top were vented from the bottom of the WUR. There is no vacuum feature for either version of the 072.

For more info on the CIS for the 911, go here:

http://members.rennlist.com/jimwms/CIS/CIShome.html

Jim good to know!! after looking a them I see the hole on the bottom of the OG one.

Here is a something I forgot to mention.

the decel valve has a dent it it, It was like that b4 I did the rebuild tho.


My other question is. what could I have done in this rebuild process that might have affected my currnet situation? or is it just a simple coincedence? Maight me easier if this informtion is out there.

car ran well b4 I did the rebuild. I backdated it and added 964 cams (timed at 1.30). new O2 sensor (aftermarket not Porsche).

thanks again.

Chris

Good point, Jim.
I checked the WUR on an '80-engine sitting on the floor, it has the 072 with the top nipple and no vac. line anywhere. The '80 WUR can be odd; I have seen one with a vacuum line from the Decel. Valve to the top of the 072 nipple.
Chris:
As I said before: Going all over the place doesn't work. The cams should be alright with 1.3mm overlap.
Trouble-shooting is a process of elimination: One identifies the components that work.
Did you service the distributor?
Do you have 12V at the WUR and AAR with engine hot and running?
For a tune-up, the sequence is: Valve clearance, Ignition timing (Check/replace plugs, wires, rotor, cap), mixture is done last and requires adjusting both fast idle screw and mixture screw several times.

Unless you have a CIS with original components that work, it's very difficult to judge from a distance what could be wrong.
It sounds like someone sqeezed the AAV to deal with a high idle. It's up to you to decide if you want to replace the AAV, get a working Bosch AAR, find an other vac can for the distributor, service the distributor, check the power supply to WUR and AAR or just keep going around in circles.
The Bosch CIS will work as intended provided all parts are good and there is no vacuum leak!
Only after the above is dealt with would I check for system- and control pressure.

I have revised my post per Jim and Gunter. The top nipple is for an atmospheric line, not a vacuum one. Sorry for any confusion.

Gunter,I did not service the Diz, how long should I assume it will take?? I only have 6-8 hours a week to work on my project. SHould I consider taking it home to do on my bench here?

I will follow through on the instructions then get back. biggest problem on saturday was I left your instructions posted here and when I got to the shop the Pelican boards were down, basically I was flying blind with no instuments at all..

I printed them out now so I have hard copy.

thanks
Chris

You really need to get it to someone with a CO & HC meter. It is very hard to do by ear. Low CO is lean, high CO is rich, high HC is a miss that could be from beaing lean (if the HC is also low) or more likely from an ignition miss. With your CO adjusted properly when you open the oil cap the idle should drop. This indicates you do not have a major vacuum leak (if you did opening the oil cap and introducing a small vacuum leak would not affect much). It also indicates your mixture is close. If the mixture was way too rich the vacuum leak would not be enough to correct it, if it was too lean it is probably still too lean and won't change much. But try to get to a CO meter, it will save a lot of time.

OK, Serviced diz today, all cleaned up and cleaned out. New plugs wires chck out with an Ohm meter- no need to replace. 12Volt +/- at WUR, 11.8 +/- A AAR.

Next?

idles fine @ 1000 rpm still cant make the lower RPM idle W/out hunting....

Chris

a couple things to look at one is the cap and rotor the other is the connection at the cdi box they are known for the wire to start rotten a few inches before the box

I got it to come down to a nice 900-950 rpm @ idle, set timing- but still a little doggy B4 3K rpm. i suppose I will never get it right untill I get a new vac advance can. I found a ton of rusty scum in the side that the retard nipple was (it was broken) as well as what looks like the remains of springs??

I am happy to have gotten it down to a nice non hunting idle when warm. we will see what it does in the AM when it is cold.

AAR is no good. I put it in the freezer all night and it is still only half open. I then added 12 volts to it for an extended time and it closes a small amount but never all the way. I will use the Coolant valve (from a vanagon) that is in there now untill I can get a used AAR --
!!!anyone have one!!! ---

Going back to it in a minute. I have a friend that has a CO sniffer so hopefully I can meet him on Saturday to do a mix check. WIl I need to have that vac advance for that??

thanks
Chris

The AAR only opens about 1/3 or 1/2, never all the way when cold.
Try spraying some WD-40 inside, then use 12V on it for 10-15 Minutes, it should close. If not, openit and try to fix it.
For a used one, advertise on the PP Classifieds.

I wouldn't trust that broken vac can.
Use a Timing light (Stroboscope) and check the advance for every 1000 RPM with vac ON and OFF; take notes!
With vac OFF, you'll see if the weights and springs are functioning at various RPM's.
A friend can sit in it and rev or you can use small stuff under the throttle-rest to set the RPM every 1k up to 5k.

Setting the mixture with a sniffer is good; keep it rich; JW likes 3.5%
I set mine by ear.