It's that time of the year AGAIN! (CIS)

[Gunter]

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

[Two Tone]

Originally posted by Gunter
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:

[T77911S]

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.

[Two Tone]

Originally posted by T77911S
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.

[T77911S]

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

[Two Tone]

Originally posted by T77911S
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?

[Gunter]

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)

[Two Tone]

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.

[favrok01]

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.

[Gunter]

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

[patkeefe]

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

[favrok01]

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

[patkeefe]

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

[favrok01]

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

[Paulporsche]

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.

[favrok01]

there isnt a decel valve on my CIS

[patkeefe]

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





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

[Gunter]

Originally posted by favrok01
there isnt a decel valve on my CIS

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.

[Two Tone]

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?

[Gunter]

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.