Another CIS mystery under way
 

heres the deal. starts up idles at 1000 continually rising as the car warms up to 1700 and stays there. new WUR and AAV.
i plugged the hoses going to the AAR (the non-electrical one) with no change.

question: is it possible for the AAV to actually work backward and open as the car warms? just a thought

Please help???:confused: :confused:

anything people

The AAV should be closed when the motor is running. It opens only during starts or whent he motor is off. Vacuum pulls the diaphragm closed when the motor is running.

Do you have a Bentley or Haynes manual?

yeahhh

I say start by checking ignition system to make sure it is working properly and timing is set properly. Then take it to someone with a sniffer and make sure the mixture is proper. It could be that the rich mixture during warmup has too much fuel, and the engine runs better when the mixture leans out. Probably incorrect, but it still doesn't hurt to make sure everything is running properly when fully warmed up.

It also won't hurt to make sure everything is connected up correctly. Thermo time switch, vacuum to the WUR, etc,..

Is your AAR closing?

I have a pre-lambda K-jet so I'm just guessing here, but take it slow and understand the components of CIS. Troubleshooting will be much easier.

i havent pulled the AAV, but it starts out in the regular cold start position, around 1100, then after about 1 minute the idle begins to climb to 1700

Jason, it's bit tough to help without more details. Why did you replace the WUR and the AAR? What were the symptoms before you replaced all those? Did you connect everything back up correctly? Do you have a CIS fuel pressure tester?

its not a matter of "hooked up correctly" everything is right. car behaves like a champ until this sprung up. no pressure tester, i have been thinking abouth one lately though

I have heard that a cracked air box will not reveal itself until the motor heats up. The sympthoms are similar to what you describe. Have you tried the carb cleaner trick to find any leaks?

Get a test from JC Whitney for less than 80 delivered. It's worth it if you have CIS.

Hey Jason.. does the idle fall back down after it warms up?

nope. it stays high

ive checked about everything except timing and advance. i guess thats next. what else could it be??

I have a "deceleration valve" on my model CIS.. you should have one also.. I disconnected it to prevent a somewhat illogical high idle.. don't need it anyway.. they can sometimes be adjusted when they screw up

Two thoughts;
1. As the engine warms up and manifold vacuum increases, the deceleration valve could open and cause a higher idle speed.
2. It could be that your idle speed is actually set at 1700 when the engine is warm and the problem is a low cold idle that will cause stalling. This could be a non-functioning AAR (You seem confused as to AAV and AAR, AAR has the electrical leads).

call it what you may. the non-electrical one has been plugged.
and the electrical one is new. kind of mind boggling

Set the idle at 950-1000 when the car is at operating temp. Then worry about why it won't idle when cold.

sounds like great advice

That's right - you don't adjust idle on a cold motor. That is not how CIS works. You set it at operating temp. 1700 warmed up is way too high. Fix that first, then go into the normal diagnostics.

checked the timing and advance-- all good.
did a pressure test on the advance unit--good

whats going on here??

that means you can't lower the idle from the 1700 rpm after it warms up??

sometimes it goes back to normal idle after it warms up and then after a while it decides to go to 1500-1700 and sometimes 1200.
im starting to think a faulty AAR

I second a prior suggestion...I would get get the car to exactly 180 (operating) degrees and turn the idle air-bypass screw clockwise until my idle was ~ 1000 to get the proper baseline established. Then I would check timing with the light and proper dwell with dwell meter. Next, take carb cleaner and spray in the vicinity of the airbox and see if the idle increases temporarily (leak). These are the quick and easier diagnostics to try. After rough check of mixture, if you don't have the CO equipment, is check the condition of your spark plugs. They will tell a lot about your mixture conditions. If they look good, odds are your mixture is ok. If they are 'whitish', probably lean...if otherwise, probably rich. Beyond this, I would consider a trusted mechanics opinion.
Ryan

My 83 is doing the same thing right now. With outside temps 50 F. and less, from cold start it slowly climbs to about 2K, then slowly works it's way down to 950, where I've set the idle. Total time ~ 10 minutes. I think that the AAR element is not warming up or it is stuck. I am going to try tapping it (per JWW) with a hammer first, then remove and clean it if it works. I may even take the time to test for voltage.

the AAV is brand new, but i suspect something is going on with it. i think its the source of this idle problem. the auto parts store i bought it from will exchange it for a new one. im gonna try that this weekend and see what happens. plugs are new

so this idle problem started happening when you changed the AAV ????

bad guess

I'd disconnect your deceleration valve to see what happens..

havent completly read the thread huh?

bad guess, LOL.. I'm just trying to get a solid baseline when this started happening and exactly how it sometimes happens..

like, "sometimes it goes back to normal idle after it warms up and then after a while it decides to go to 1500-1700 and sometimes 1200".. so this happened at idle all by itself, or after decelerating..
and my suggestion to eliminate the deceleration valve is that it can sometimes confuse the answer. the deceleration valve can cause problems with idle.. also the AAV and vacuum leaks are the routine answers. even the accelerator pedal, cable, or throttle valve binding..

its not the same everytime. sometimes it happens after 2 minutes from a cold start, and sometimes it happens after an hour of driving. it started happening 5 days ago, 2 months after replacing anything

ive tried just about everything short of pressure testing the CIS.
ill put money on the AAR being defective

the AAR has the elec connections..then when you clamp the AAR hose at high idle, the high idle decreases.. the AAV may cause cold start surging

If it looks like a nail, hammer it! I was experiencing long warmups due to idle staying high, and fan pushing cold air through engine compartment. I read another post (oh the power of information) suggesting a light tap with a hammer to the AAR and see if the idle drops... and it did. Now I will take the AAR off and give it a good cleaning. Thanks JW!

i bet youve never heard this one. i pulled the AAR last night to exchange it, so i figure lets go ahead and test it on the kitchen table. i hook up a 12V power source and over about 1 minute or so, watch it close completely.
so i think, well there goes that theory. i leave it hooked up for a while to make sure it stays closed. i start to wonder if just being closed all the way is enough to prevent air from pasing through and decide to blow through it, and i can. not a little either, a lot!!!!
the disk that is inside of the valve was not creating a good enough seal to prevent the air from passing. is that unreal or what!!??

im gonna put in the new one today and hopefully cure the high idle

im goin crazy. its up to 4 now. ive had 4 AAR's and i can blow through each one of them while fully closed. per the haynes manual i disconnected a hose from the AAR plugged both openings and the problem is gone (high idle when warm). am i crazy or are all the new AAR's faulty. help please

I don't think the AAR's are "air tight" even when fully closed; see the comment about notches in the shutter in the following thread:

http://forums.pelicanparts.com/showthread.php?s=&threadid=64178&highlight=Auxilli ary+AND+Air+AND+Regulator

Jim

I just went thru a lot of CIS books.. and the AAR test is routine.. nowhere is it mentioned that it you should pass air thru it when warm to test for air tight.....Ron

Air passes one way but not the other when closed. That is by design. You are blowing in the wrong end.

im blowing in the wrong end......
stupid me
air passes both ways genius

I had always been told that some air will pass through the AAR. In fact, even with the car warm, I will return to it, fire it up, and it high idles for a short bit of time. My assumption was that current was shutting it down again. God knows the footprint of the base of the AAR is wide enough to pick up heat from the block it sits on. That has to effect things as well.

But I read this thread and I keep coming back to vaccum lines that appear near new but, under heat, expand and show minute cracks that allow air in. That would at least explain the higher idle. Or a crack in the plenum or loose hose on the backside of the throttle body.

What happens to the high idle when you pull the oil cap? Could this be as simple as a bad gasket at the cap?

Sorry to be so clueless. I am dying to hear the resolution to this one.

John