Full Version: high idle
I'm having a bit of an unusual problem. It started last year when I had the car repainted. I disconnected all wires/hoses going to the outside of the engine compartment for painting purposes. Ever since reconnecting everything it has idled high (1600 rpm to be exact). I looked over all of the connections and everything seems to be fine. Do I have a stuck high-idle valve? I'm stumped. Any suggestions would be helpful. Thanks in advance.
Sounds like the AAR may be hooked up wrong or has failed. Plug the hose that goes to the plenum and see if it settles down.
In my experience a high or sporadic idle is generally indicative of a vacuum leak. Double check your vacuum hoses to make sure all connections are tight and that you didn't accidentally rip or tear one when removing/reinstalling it- if the hoses are old enough it doesn't take much to break them.
QUOTE(yeahmag @ Mar 30 2009, 02:45 PM) 
Sounds like the AAR may be hooked up wrong or has failed. Plug the hose that goes to the plenum and see if it settles down.
Call me stupid, but what is the AAR? Is it safe to drive the car like this? It figures this would happen as I am trying to sell the thing!
Auxiliary Air Regulator. Here's the Pelican Parts description of it:
The auxiliary air regulator is used to provide the engine with extra air when it is cold. When the temperature reaches a certain point the valve closes and prevents additional air from entering the injection system. If the unit fails, it can cause a high idle, as extra air is entering the engine, or it can cause the engine to idle rough, as the extra air causes the motor to run lean. A good way to check the unit is to remove it when the engine has heated up. If you can blow air through the valve, the unit is probably defective and needs to be replaced.
So yeah, you may want to test that out and see what happens. If no change, pursue vacuum leaks as I said. Go to the link below to see a picture of the AAR- it's about halfway down the page.
http://www.pelicanparts.com/cgi-bin/ksearc...022-906-045-OEM
Good luck and keep us updated.
The auxiliary air regulator is used to provide the engine with extra air when it is cold. When the temperature reaches a certain point the valve closes and prevents additional air from entering the injection system. If the unit fails, it can cause a high idle, as extra air is entering the engine, or it can cause the engine to idle rough, as the extra air causes the motor to run lean. A good way to check the unit is to remove it when the engine has heated up. If you can blow air through the valve, the unit is probably defective and needs to be replaced.
So yeah, you may want to test that out and see what happens. If no change, pursue vacuum leaks as I said. Go to the link below to see a picture of the AAR- it's about halfway down the page.
http://www.pelicanparts.com/cgi-bin/ksearc...022-906-045-OEM
Good luck and keep us updated.
Simple way to isolate a vacuum leak.
disconnect every hose that goes into the plenum.
Cap the plenum outlet holes with properly sized rubber vacuum plugs (napa, or autozone)
The only one that needs to be plugged in is the MPS.
If that works, add one hose at a time until the problem comes back...then you find the system that is leaking.
If that is done properly and the car still idles to high, you have a leak in your intake...could be a cracked plenum, could be the big hoses going to the runners, could be the runner bolted to the head.
I remove the intake runners and replace the gaskets at the head.
It goes like this.
head---thin gasket---fat spacer---thin gasket---intake runner.
I also (Cap'n hates this) use a very thin application of RTV sealant on each face of each gasket to ensure an airtight seal.
Now look at the fat rubber hoses (NLA) that connect the runners to the plenum...those need clamps at this point in life...get some good clamps to seal those up.
From there, if your idle is still to high, you may have a cracked plenum.
Before you do any of that...check the timing..it could be off.
rIch
disconnect every hose that goes into the plenum.
Cap the plenum outlet holes with properly sized rubber vacuum plugs (napa, or autozone)
The only one that needs to be plugged in is the MPS.
If that works, add one hose at a time until the problem comes back...then you find the system that is leaking.
If that is done properly and the car still idles to high, you have a leak in your intake...could be a cracked plenum, could be the big hoses going to the runners, could be the runner bolted to the head.
I remove the intake runners and replace the gaskets at the head.
It goes like this.
head---thin gasket---fat spacer---thin gasket---intake runner.
I also (Cap'n hates this) use a very thin application of RTV sealant on each face of each gasket to ensure an airtight seal.
Now look at the fat rubber hoses (NLA) that connect the runners to the plenum...those need clamps at this point in life...get some good clamps to seal those up.
From there, if your idle is still to high, you may have a cracked plenum.
Before you do any of that...check the timing..it could be off.
rIch
QUOTE(r_towle @ Mar 31 2009, 05:39 PM)
I remove the intake runners and replace the gaskets at the head.
It goes like this.
head---thin gasket---fat spacer---thin gasket---intake runner.
There are thin gaskets on either side of the fat spacers??? I've never seen these on any of the motors I've disassembled. Where can I get these?
Its the same gasket as the inner one.
Rich
Rich
I am confused. I only see one gasket/spacer between the head and the intake runner.
What type of RTV sealant do you recommend? I've got some RTV silicone sealant but it doesn't indicate a temp range.
What type of RTV sealant do you recommend? I've got some RTV silicone sealant but it doesn't indicate a temp range.
Black or copper...
Both work for me.
Dont use a boatload...but enough to seal them
RIch
Both work for me.
Dont use a boatload...but enough to seal them
RIch
Thanks for all the replies. I tried testing the AAR and it seems to be causing the problem. Another question: should there be a constant 12 volts going to the AAR?
Another point. Pelican parts wants $258 for the part...ouch. I did a search and found them as low as $49 for a rebuilt one. Any recommendation where to get a good one? Are they rebuildable by the home mechanic?
Thanks in advance, Todd.
Another point. Pelican parts wants $258 for the part...ouch. I did a search and found them as low as $49 for a rebuilt one. Any recommendation where to get a good one? Are they rebuildable by the home mechanic?
Thanks in advance, Todd.
Yes, constand 12v to the AAR keeps the element inside hot, which keep the valve shut.
Some people have had success by squirting a bit of PBBlaster or Kroil into the air pipes to free a stuck mechanism.
Some people have had success by squirting a bit of PBBlaster or Kroil into the air pipes to free a stuck mechanism.
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