Since you have a 3.0 from an SC, why not get the Bentley SC Repair Manual?
You'll love it!

Love is a strong word but I am becoming very close to mine....;)
Got it last fall from Pelican.

This is my car:
http://forums.pelicanparts.com/uploa...1179158446.jpg

if you completely block the intake horn, it should stall out. if you remove the oil cap, you should noticed a very slight dip in RPM.

It seems to me that it should stall too, but RPM rises when the air horn is completely covered while at warm idle.

Removing the oil cap has zero effect on idle speed.

sounds like u have a BIG air leak. i still think it is in the plumbing for the AAR and AAV.

Yeah, it sure seems that way. I just hope it will still run properly when warm after I find and fix the problem.

Here's what I'm thinking now:
It would seem to me that given that I have a significant air leak (if indeed it is true that the engine should stall if the intake horn is completely covered) it would seem that I should find and fix the leak(s) first.
If I block the horn at warm idle I should be able to discover where its getting air from with starting fluid or similar, yes? After I fix any air leak then I can go about diagnosing further problems if the engine still behaves badly when cold (or warm). If the vacuum leak is in the AAV or AAR plumbing this test should find it.

Thoughts anyone?

Do not block the intake when checking for vac leaks.
Since the RPM doesn't drop when opening the oil cap, check both ends of the breather hoses and put clamps on the ends.
I use Acetylene for testing but the next best thing is a Propane torch with a small nozzle.
The usual suspects are around the airbox, the rubber sleeves on the intake runners, the gaskets between runners and heads, the vac line for the brake booster........................
Until you find the leaks, there is no use trying to set timing or mixture.
It helps if you don't have the fan blower, A/C and cruise control in the way. (More room in the bay)

Gunter,

Thanks for the advice.

I have acetylene so I'll use that. I can see where it would give more control in pinpointing leaks than a can of ether.

I'll report what I find.

what would make the engine slow to rev back down to 800?
my car revs fast but is very slow to get back to zero.
throttle is not sticky and when moved by hand it dousnt matter, quik up and down still revs stay hi for 30 secs.

An exact description of the engine would help.
Like year/type?
OEM Bosch CDI-CIS?
What mods?

fav
Probably the decel valve; keeps the revs up a bit and slowly backs them down. It's an emissions thing.

how can i test this decel valve/
this is a 81 sc engine

Plug the vacuum tube on the decel valve, and see if the condition stops.

is that 17a on the CIS diagram on SOUK'S link?

If you search you will find you can adjust the decel valves, which control how fast your engine speed returns to idle. If you have the small, vertical type, w/ a hose off the top, you can adjust the brass nozzle on top w/ the nut that surrounds it. If you have the newer type that looks kind of like a small saucer on its side, you can remove it and compress i slightly in a vice. Or you can remove and/or plug the lines to it and have the engine speed drop more quickly. A lot of posters seem to do that. I am assuming her that your idle speed and mixture are set correctly.

there isnt a decel valve on my CIS


http://forums.pelicanparts.com/uploa...1179872165.jpg

I think I found it.
And, BTW, I listen to anything Paulporsche says about CIS. He is quite astute in the K-Jetronic stuff.


http://forums.pelicanparts.com/uploa...1179873889.jpg


Edit:
OOPS! What year is your CIS system. I think the later years may be a bit different.

Some friendly observations: :)

I remember from some of your other posts that you had problems with CIS, didn't like CIS and wanted carbs.
Repeated suggestions were that you need to get some books on CIS, do more searches and use some of the excellent articles on K-Jetronic posted by others right here on PP.

If you cannot even recognize the Decel Valve, how do you expect to understand the many other components of your CIS or how they work?

Do yourself a favor and learn about your K-Jetronic.
The DV in the picture is adjustable; your stock '82 DV is most likely not adjustable.

Unless you study and learn about CIS, you'll keep going around in circles.
CIS works great if it is set up right.
That means all components working, correct wiring, correct vacuum lines and no leaks.

BTW: With carbs, you'll have the same issues of learning how they work, correct jetting etc.

Take the plunge, read and study about CIS. SmileWavy

It's the AAR
 

Finally got a chance today to mess with the car a bit.
During the high idle after cold start I pinched off the rubber hose between the AAR and the Intake man. I was able to completely control the engine speed by how much I pinched off the hose. I brought it down to what sounded like a normal high idle for warm up.
While I was holding on to the pliers I was able to feel the 'snap' coming from the AAR when it finally decided to move which corresponded to the RPM's dropping down to normal.
It would seem that the problem is in the AAR and/or the plumbing to same. As I understand it, the movement of the AAR should be gradual and not a sudden snap.

Re. the cold start problem: I tried lifting the air plate with the key on to inject some fuel into the manifold. It cold started instantly instead of after much cranking. This suggests to me that it may not be getting extra fuel on a cold start due to a faulty cold start injector or a thermo-switch problem. I will look into that after I fix the AAR.

Any thoughts?

Open the clamp on the hose for the AAR. Move the hose just enough to be able to spray WD-40 into the AAR so the mechanism can slide.

As for cold start:
There should be a wire from the starter solenoid going to the Therm-timer (TT) and then to the cold start valve (CSV).

Check the Solenoid for 2 wires: 1 from the ignition key, 1 going to the TT. When cranking, there should be 12V on the wire going to the TT as long as the Solenoid is energized.
12V from the TT to the CSV is only for a few seconds to energize the CSV.

Gunter has given you a test for the CSV. You can try that and let us know the results. As a general rule, however, if the engine starts, then the CSV is working, although there are variables, such as the length of firing and whether it is leaking.

Your symptoms sound to me more like your AAR is not operating correctly, but it is at least working. Check out mystery train's thread on AAR repair.

I am thinking your WUR is not operating correctly. I can't remember, have you checked your fuel pressures? I think your control pressure may be off, and your mixture setting may also be set slightly off.

The photo shows the later style AAR which is not adjustable per se, as Gunter said. There is a fix for it however, which involves removing it and squeezing it in a vice tom reduce its dimension by 1 mm. This "adjusts" it into the correct config. You may want to replace it w/ another, maybe earlier, one from a wrecker, or remove it as many have.

EDIT: Sorry, above paragraph refers to Decel Valve not AAR

someone else had a question about the firing voltage of the CSV ( this is not related to the problem). but if you take out the CSV, try firing it with a 9v battery. someone else said theirs fired at around 10v and didnt know if that was correct or not.

you can use a hand vacuum pump on the decel valve. i believe mine opened around 20in. ?? you should not be able to blow through the big fittings with it closed.

+1 on what gunter said about it working great, it is also reliable and yes simple compared to carbs, only 1 adjustment on CIS, plus a LOT better gas mileage. i am getting 20+ and i have it set rich. dont get me wrong, i love the sound and performance of carbs, i just cant afford them and i have a good CIS system if the FD ever goes bad, hello carbs.
learn CIS, its not that hard once you understand what role each part plays.

my money is still on the AAV and/or the plumbing to it and the AAR.

if the car is lean due to an air leak, lifting the sensor plate compensates for the air leak.

MY problem was fixed by the adjustment of the AAV. Thank you Paulporsche & Gunter. It does go down quicker but not as fast as i am used to. it is turned all the way down.
i think i will do a parts swap with another CIS i have and see if its just a "old" AAV or if its just sticky.

here you go Jeff.

http://forums.pelicanparts.com/uploa...1193280955.gif

Giving this the annual:
http://forums.pelicanparts.com/uploa...1224595981.jpg
(BUMP)

For all the CIS NOOBs that might be wondering what's going on, now that the temps are dropping...

Nice bump :D Ouch...

It was 40 degrees during my commute this morning. I'm sure some CIS engines out there were doing some hunting to start out their morning.

No difference with my start at 39 degrees yesterday morning.

1st turn of key without idle hunting.

Yeah, same for me. Started as soon as the key was touched and needed very little help with the idle (I removed my AAR long ago). However, things smell a tad rich for me, in the cool weather. I'll be checking my pressures and checking AFRs with my LM1, just to be sure.

Been doing lots of reading here..
OK, i imported my 1975 targa from Arizona in june this year and i believe the car had not been started in about a year or so.
I have rebuilt the whole car, interior, paint, seals etc....no rust.
When it came to the engine i only gave it a clean up and replaced the rocker seals and the rubber rings on the inlet manifolds, also i noticed that the plunger thing on the fuel distributor was stuck but this was sorted with some carb cleaner and then i was able to move it up & down freely, - Sorted I think ??
When it came to starting the car for the first time after all this it started very very first turn !!
i could'nt beleive it that it started so easy, but it seems to be running very very rich, blackish smoke and i know by the smell of it !! also idling high, It takes throttle no prob and its very responsive
These are my thoughts.....
The Cold Start Valve is staying open, is this possible ????
The WUR is faulty....Any way of testing this ?? i have no way to carry out a pressure test...
Also over here in Ireland we use 95 octane but i dont think this would have a big affect....
Previously on the forum i had some issues about the connections to the WUR/CSV/ etc. so im hoping these are ok.
The Decel valve was disconnected when i got it so i have left it like this.......

Over here in Ireland there is not many experts for these motors, and i have to say id be lost without this forum...

PMoore,

I would suggest you start a new thread w/ this post.

You will prpbably get more responses and ones that are specific to your problem.

BTW you probably should get a CIS fuel pressure gauge which is helpful in tracking down CIS problems. And check your mixture so that you have a baseline, especially if you think it is running rich. JW recommends 3.5% which is about 13.1 or .2 to 1 AFR.

Quick Q,
This CIS fuel pressure gauge you gentlemen are refering to, is that a designated part? or will any fuel pressure gauge do the job?
Cheers, Col.

Any guage that has a 0-100 psig range will work, but it isn't just the gauge. One needs the correct connectors/fettings, lines and a valve to isolate the system pressure when testing.

does pelican offer a tool to test cis??

CIS Question
 

There is a vacuum part over by the Oil Fill tube, right above the spark plugs, that has two big hoses going into the back of it and a vacuum line coming out the front... The vacuum hose is quite long and goes over to the driver side of the engine bay. Question... what does this vacuum line get connected to? I was doing a clutch job and this got disconnected and I have no idea where it goes... The pics Ive seen seem to show it connected to the throttle body... thanks...

Stating the year/type wouldn't hurt.

I assume it's a later SC with Lambda and you're describing the Deceleration Valve The small vac line goes to the back of the TB right next to the vac advance connection for the distributor.
There are several small connection nipples; pick one and plug any open ones.

Just saw a few threads on CIS that appear to be weather related....

A very old thread, yet I have visited it regularly. Winter is a bit late here this year...
Each fall I have to turn my mixture screw 1/8 turn CW, each spring I dial it back again.
(sometimes I need a small adjustment for our version of the MOT, resetting it to where it was after that)
This thread together with http://forums.pelicanparts.com/porsche-911-technical-forum/232089-cis-idle-speed-mixture-setting-without-analyzer.html has kept me sane driving my CIS car all year round.

Thanks for this valuable information, Souk!

Talk about a way back machine ;)

My last post on this thread is about as old as my youngest born. I'm glad folks still find this stuff useful. I haven't touched a CIS car in years...probably couldn't find the mixture screw ;)

Keep the CIS alive boys!

Souk

Hahaha, I've been driving this car for 11 years now and I've visited both of your CIS threads multiple times. It's about time I said: thank you :D.

I forgot about this thread. I'm glad I subscribed in '04. I still adjust twice a year. I keep the allen wrench in my glovebox, and it works every time! LONG LIVE CIS! :D