HIgh Idle

[BRP83SC]

Where is the Auxiliary air valve located (when facing the engine)? and is there any way to test it.

Yesterday, while driving my 83 died in traffic; the car burped a little and the idle when down to nothing.

unstrapping the air cover, i could hear the pop off snap down.

got back into the car and it started just fine.

after driving about a mile, i idle increased to about 1800 and stayed there. coming out of work yesterday evening, started the car and notice the idle speed to oscillating until warm.

after warm, idle increased to about 1800 and stayed there and adjusting the idle has no affect.

According the Jim William's CIS overview, these are the things associated with the Auxiliary air valve not close.

hence the leadoff question

[Gunter]

AAV doesn't open or close; the AAR does.

The AAR can be checked for correct operation but I suggest that you get yourself more familiar with CIS and all its components.
Do you have the Bentley SC Repair Manual?

If the pop-off valve snapped down when you opened the air filter cover, it may be installed wrong.
Post a picture of the pop-off so we can see if it's correct.

Do you have the Bentley?

[SC-targa]

Check for a vacuum leak too.

[BRP83SC]

Originally Posted by Gunter

AAV doesn't open or close; the AAR does.

The AAR can be checked for correct operation but I suggest that you get yourself more familiar with CIS and all its components.
Do you have the Bentley SC Repair Manual?

If the pop-off valve snapped down when you opened the air filter cover, it may be installed wrong.
Post a picture of the pop-off so we can see if it's correct.

Do you have the Bentley?

Yes, I have the bentley and was reviewing last knight as well as Jim's site. Maybe it was late but thought or mis quoted when stating the AAV opens/shuts.

regarding the pop-off; I will post a picture this evening. Last night in researching this issue, I came accross a photo of a pop-off value. Again, late night but it the photo suggested the value opens towards the front of the car. Mine open towards the rear of the car. The PO installed it or had someone install it

[BRP83SC]

Originally Posted by SC-targa

Check for a vacuum leak too.

I have seen this suggestion on this forum and in some other publications. The question I had is does that involve some sort of tool or merely a visual inspection?

[ossiblue]

Originally Posted by BRP83SC

regarding the pop-off; I will post a picture this evening. Last night in researching this issue, I came accross a photo of a pop-off value. Again, late night but it the photo suggested the value opens towards the front of the car. Mine open towards the rear of the car. The PO installed it or had someone install it

From you post, it is installed backward that is why it stuck open--it wedged on the sloping air cleaner element.

Originally Posted by BRP83SC

I have seen this suggestion on this forum and in some other publications. The question I had is does that involve some sort of tool or merely a visual inspection?

It involves, for the DIY, both visual inspection and the use of solvents like brake cleaner which is sprayed around suspicious areas to find changes in idle, indicating a vacuum leak. For the pros, there are smoke machines, but those are expensive and usually not found in home garages.

If you suspect a vacuum leak, you will have lots of help here in tracking it down. A bit of patience and perseverance will pay off. Keep us informed of what you find.

[T77911S]

the hinge should be towards you when looking at it.

[T77911S]

if that is ok, it may be the decel valve.

[boyt911sc]

Originally Posted by BRP83SC

Where is the Auxiliary air valve located (when facing the engine)? and is there any way to test it.

Yesterday, while driving my 83 died in traffic; the car burped a little and the idle when down to nothing.

unstrapping the air cover, i could hear the pop off snap down.

got back into the car and it started just fine.

after driving about a mile, i idle increased to about 1800 and stayed there. coming out of work yesterday evening, started the car and notice the idle speed to oscillating until warm.

after warm, idle increased to about 1800 and stayed there and adjusting the idle has no affect.

According the Jim William's CIS overview, these are the things associated with the Auxiliary air valve not close.

hence the leadoff question

Brad,

The way you descibed the condition of your car, I would bet that you have unmetered air. One very simple way to determine if you have unmetered air is to remove the oil filler cap when the engine fully warmed up and running. Once you removed the oil cap, you'll notice an RPM drop. If you don't get any change in RPM (idle speed going down), you got unmetered air going into the system.

The second option to locate your vacuum is to pressurize your system and look for air leak/s. Concentrate in areas where there are connections like rubber hoses, boots, rubber seals, etc. The air box seams, pop valve seat, brake vacuum line, etc. are also candidates for vacuum leak.

There are too many spots where vacuum leak could occur. Not being able to find one does not mean you don't have any. So stop the guess work and do the investigation wisely. Using propane, carburator cleaner, starter fluid, etc. are not as reliable and dependable than using compressed air.

Check the AAR located near the intake manifolds #4 & #6 (passenger-side ). I doubt this is the culprit. Keep us posted.

Tony

[BRP83SC]

Originally Posted by boyt911sc

Brad,

The way you descibed the condition of your car, I would bet that you have unmetered air. One very simple way to determine if you have unmetered air is to remove the oil filler cap when the engine fully warmed up and running. Once you removed the oil cap, you'll notice an RPM drop. If you don't get any change in RPM (idle speed going down), you got unmetered air going into the system.

The second option to locate your vacuum is to pressurize your system and look for air leak/s. Concentrate in areas where there are connections like rubber hoses, boots, rubber seals, etc. The air box seams, pop valve seat, brake vacuum line, etc. are also candidates for vacuum leak.

There are too many spots where vacuum leak could occur. Not being able to find one does not mean you don't have any. So stop the guess work and do the investigation wisely. Using propane, carburator cleaner, starter fluid, etc. are not as reliable and dependable than using compressed air.

Check the AAR located near the intake manifolds #4 & #6 (passenger-side ). I doubt this is the culprit. Keep us posted.

Tony

Once I leave work, I will verify the pop-off hinge direction and perform the oil filler test.

I have continued searching this topic in this forum and have found more information to get me up to speed. I will be checking hoses as described above in in other posts.

I appreciate the help and support.

[BRP83SC]

Originally Posted by T77911S

the hinge should be towards you when looking at it.

Great, not the case; however, this will need to after I resolve the high idle issue. Too bad I can't rotate the photo and have the car follow suit.

[BRP83SC]

Originally Posted by boyt911sc

Brad,

The way you descibed the condition of your car, I would bet that you have unmetered air. One very simple way to determine if you have unmetered air is to remove the oil filler cap when the engine fully warmed up and running. Once you removed the oil cap, you'll notice an RPM drop. If you don't get any change in RPM (idle speed going down), you got unmetered air going into the system.

The second option to locate your vacuum is to pressurize your system and look for air leak/s. Concentrate in areas where there are connections like rubber hoses, boots, rubber seals, etc. The air box seams, pop valve seat, brake vacuum line, etc. are also candidates for vacuum leak.

There are too many spots where vacuum leak could occur. Not being able to find one does not mean you don't have any. So stop the guess work and do the investigation wisely. Using propane, carburator cleaner, starter fluid, etc. are not as reliable and dependable than using compressed air.

Check the AAR located near the intake manifolds #4 & #6 (passenger-side ). I doubt this is the culprit. Keep us posted.

Tony

With the car warm, I removed the oil cap; the idle did not change at all. How tight does the pop off value need to be in terms of placement in the air box.

besides it being installed backwards, it appears a little loose as in the proxy is given way. I can wiggle it with a little force; however, I would not characterize it as about to fall out either.

[T77911S]

check the air filter, see if it shows signs of it hitting it.

[BRP83SC]

While the car was running, the idle was about 1200 (less than the normal 1800 since this issue started).

I took a small screw driver and slightly pry opened the pop-off and the idle increased a little bit.

I did a couple more time with the same result. when i stopped the idle remained at 1800 until I turned the car off.

In my previous post response, I mentioned that the pop off valve is "glue" in but not rock solidly. if a pop off valve is installed properly, should I be able to move it at all?


if I elect to redo the install of the pop off, what proxy should I use?

[ossiblue]

Originally Posted by BRP83SC

With the car warm, I removed the oil cap; the idle did not change at all. How tight does the pop off value need to be in terms of placement in the air box.

besides it being installed backwards, it appears a little loose as in the proxy is given way. I can wiggle it with a little force; however, I would not characterize it as about to fall out either.

As Tony said, you may have more than one vacuum leak but the looseness of the pop-off valve is certainly highly suspect. From your photo it actually looks like it is installed using silicone but that may be just the picture. Regardless, it should not be loose. This is an opportunity to install it correctly. I'd suggest you remove it now, clean up the box and valve body, and reinstall it correctly using either epoxy or urethane adhesive. That will remove the valve as a possible air leak.

If that doesn't improve your idle problem, follow the suggestions for finding vacuum leaks. Be patient and thorough. It's a PITA, but it is necessary to have a well running CIS.

Let us know what you do and what you find. Good luck.

edit: You posted while I was typing. Most here use two part JB Weld for epoxy. Not sure of the brand of urethane, but if you type "urethane" into the search function, a recent thread should appear where it is mentioned by brand name, I think, as I remember reading about it just a few days ago.

BTW, I just noticed your location--I'm just a bit up the coast from you. Feel free to contact me directly if you have any questions. Shoot me a PM and I'll give you the phone number.

[BRP83SC]

Originally Posted by ossiblue

As Tony said, you may have more than one vacuum leak but the looseness of the pop-off valve is certainly highly suspect. From your photo it actually looks like it is installed using silicone but that may be just the picture. Regardless, it should not be loose. This is an opportunity to install it correctly. I'd suggest you remove it now, clean up the box and valve body, and reinstall it correctly using either epoxy or urethane adhesive. That will remove the valve as a possible air leak.

If that doesn't improve your idle problem, follow the suggestions for finding vacuum leaks. Be patient and thorough. It's a PITA, but it is necessary to have a well running CIS.

Let us know what you do and what you find. Good luck.

edit: You posted while I was typing. Most here use two part JB Weld for epoxy. Not sure of the brand of urethane, but if you type "urethane" into the search function, a recent thread should appear where it is mentioned by brand name, I think, as I remember reading about it just a few days ago.

BTW, I just noticed your location--I'm just a bit up the coast from you. Feel free to contact me directly if you have any questions. Shoot me a PM and I'll give you the phone number.

Appreciate it and yes it appears to be a silicone

I also found this comment on the Epoxy:

Comments: What is the best epoxy to use brand name to fix the pop off valve in position
April 27, 2009
Followup from the Pelican Staff: I think a standard hardware store extra strength epoxy would do the trick. I've used that before with excellent results. Loctite is a great brand, I've also used Devcon with good success too. - Wayne at Pelican Parts

[ossiblue]

Here's the link that talks about urethane:
Can I.....

Check posts #13-18 in the thread.

[Gunter]

Originally Posted by BRP83SC

While the car was running, the idle was about 1200 (less than the normal 1800 since this issue started).

I took a small screw driver and slightly pry opened the pop-off and the idle increased a little bit.

I did a couple more time with the same result. when i stopped the idle remained at 1800 until I turned the car off.

In my previous post response, I mentioned that the pop off valve is "glue" in but not rock solidly. if a pop off valve is installed properly, should I be able to move it at all?


if I elect to redo the install of the pop off, what proxy should I use?

I suspected the pop-off from the start.
Aside from being installed the wrong way, the picture makes me think that it was done pretty sloppy and that's most likely the reason for wrong air entering the system.

You can try to re-glue the valve but, if the hole is over-sized, it may not work.
Meaning a new box.
The pop-off valve has to be tight so that the mixture can be set correctly.
Do that first, then check for vacuum leaks per suggestions like oil cap etc. and only when there are no vac leaks, set the mixture and correct idle.

Let us know.

[ossiblue]

Just a follow-up. Inspired by Gunter's post, I took another look at your pic of the valve. It looks like it is not even sitting flush on the bottom of the airbox, but rather resting on the ribs. If so, that will definitely be leaking from the way it was installed. If the hole for the valve is not too large as Gunter mentioned, then before you reinstall the valve correctly, file down the ribs so the base of the valve is flush with the airbox. Then apply the adhesive and seat the valve firmly.

[BRP83SC]

Originally Posted by ossiblue

Just a follow-up. Inspired by Gunter's post, I took another look at your pic of the valve. It looks like it is not even sitting flush on the bottom of the airbox, but rather resting on the ribs. If so, that will definitely be leaking from the way it was installed. If the hole for the valve is not too large as Gunter mentioned, then before you reinstall the valve correctly, file down the ribs so the base of the valve is flush with the airbox. Then apply the adhesive and seat the valve firmly.

THANK YOU....

When I was examining it yesterday, it appears that the valve is sitting on the ribs but did not immediately tie sitting on the ribs to air leaking in. if the PO used silicone to attach the valve, there is a good chance the silicone filled the gaps between the ribs--until now. All good speculation and I will confirm when I take it apart this weekend.

Your observation and comments were timely and helpful.

Right now, I am praying that the hole was properly sized as I am not looking for (time and $$) to replaceing the airbox.