Jumping idle, IAC valve

The problem is that after the engine (1991 Accord 2.2) is fully warm, the
idle jumps up and down. It seems to almost stall, the idle air control
reacts, and the idle shoots up, too high. It again falls down to almost
stalling. This continues to repeat.
So I took the Idle Air Control (IAC) from the intake manifold. The metal
screen was for the larger part blocked with black soot. Cleaned this.
This did not complete solve the problem. I think also the electrical motor
is sticky. Can anyone on the list give me some hints on how to get this
smooth?
How can I remove this motor from the IAC assembly??
Should I spray WD40 at the IAC valve, or will this ruin things?

Thanks, Jan
1991 Accord Aerodeck (=wagon) 2.2i EX

 

I believe you are on the right track. The IAC is probably the source of
the problem. I suggest that you buy a repair manual for the vehicle. It
should have the instuctions for removing the IAC and it might even give
instuctions on how to clean and lubricate it and related parts. Some auto
parts stores such as Kragens and Auto Depot have manuals for sale. Barnes
and Noble has some manuals but not a wide selection. A company called
Hayes makes one for every model. You can call Haynes at this number
1-805-498-6703. The one for your car has this code number 42012. If you
can't afford to or don't want to buy a manual--just read it at the store
or Barnes and Noble and place it back on the shelf.

 

I believe you are on the right track. The IAC is probably the source of
the problem. I suggest that you buy a repair manual for the vehicle. It
should have the instuctions for removing the IAC and it might even give
instuctions on how to clean and lubricate it and related parts. Some auto
parts stores such as Kragens and Auto Depot have manuals for sale. Barnes
and Noble has some manuals but not a wide selection. A company called
Hayes makes one for every model. You can call Haynes at this number
1-805-498-6703. The one for your car has this code number 42012. If you
can't afford to or don't want to buy a manual--just read it at the store
or Barnes and Noble and place it back on the shelf.

 

I believe you are on the right track. The IAC is probably the source of
the problem. I suggest that you buy a repair manual for the vehicle. It
should have the instuctions for removing the IAC and it might even give
instuctions on how to clean and lubricate it and related parts. Some auto
parts stores such as Kragens and Auto Depot have manuals for sale. Barnes
and Noble has some manuals but not a wide selection. A company called
Hayes makes one for every model. You can call Haynes at this number
1-805-498-6703. The one for your car has this code number 42012. If you
can't afford to or don't want to buy a manual--just read it at the store
or Barnes and Noble and place it back on the shelf.

 

This did not complete solve the problem. I think also the electrical motor

Don't know about the '91 Accord but the IAC on my '94 Civic does not
have a motor. The valve is operated by an electromagnet. I doubt you can
get it apart and get it back working again afterwards.

WD40 should do no damage but may not dissolve the gunk in the valve.
Carburetor cleaner (or throttle body cleaner) will get rid of the
buildup. Don't know if it would cause damage, but I would use it on my
own car if need be.

 

This did not complete solve the problem. I think also the electrical motor

Don't know about the '91 Accord but the IAC on my '94 Civic does not
have a motor. The valve is operated by an electromagnet. I doubt you can
get it apart and get it back working again afterwards.

WD40 should do no damage but may not dissolve the gunk in the valve.
Carburetor cleaner (or throttle body cleaner) will get rid of the
buildup. Don't know if it would cause damage, but I would use it on my
own car if need be.

 

This did not complete solve the problem. I think also the electrical motor

Don't know about the '91 Accord but the IAC on my '94 Civic does not
have a motor. The valve is operated by an electromagnet. I doubt you can
get it apart and get it back working again afterwards.

WD40 should do no damage but may not dissolve the gunk in the valve.
Carburetor cleaner (or throttle body cleaner) will get rid of the
buildup. Don't know if it would cause damage, but I would use it on my
own car if need be.

 

I'll buy carburetor cleaner and spray this at the IAC valve.
It really does not seem like the motor part can be taken from the valve
assembly. I checked
on the Honda Majestic parts site, there is no exploded view for the IAC
valve assembly.
Also in my Haynes manual nothing is mentioned about taking this apart...
So I'll go for spray cleaning....

Thanks,
Jan

 

I'll buy carburetor cleaner and spray this at the IAC valve.
It really does not seem like the motor part can be taken from the valve
assembly. I checked
on the Honda Majestic parts site, there is no exploded view for the IAC
valve assembly.
Also in my Haynes manual nothing is mentioned about taking this apart...
So I'll go for spray cleaning....

Thanks,
Jan

 

I'll buy carburetor cleaner and spray this at the IAC valve.
It really does not seem like the motor part can be taken from the valve
assembly. I checked
on the Honda Majestic parts site, there is no exploded view for the IAC
valve assembly.
Also in my Haynes manual nothing is mentioned about taking this apart...
So I'll go for spray cleaning....

Thanks,
Jan

 

Don't use WD-40. It causes rubber to swell.

Use carb cleaner or throttle body cleaner on the valve while the car is
running. You want the solvent sucked out as quickly as possible so it
doesn't damage the valve or deposit soot farther down into it.

Also check: thermostat, EGR valve, and PCV valve

 

Don't use WD-40. It causes rubber to swell.

Use carb cleaner or throttle body cleaner on the valve while the car is
running. You want the solvent sucked out as quickly as possible so it
doesn't damage the valve or deposit soot farther down into it.

Also check: thermostat, EGR valve, and PCV valve

 

Don't use WD-40. It causes rubber to swell.

Use carb cleaner or throttle body cleaner on the valve while the car is
running. You want the solvent sucked out as quickly as possible so it
doesn't damage the valve or deposit soot farther down into it.

Also check: thermostat, EGR valve, and PCV valve

 

I'd check your Fast Idle valve.

 

I'd check your Fast Idle valve.

 

I'd check your Fast Idle valve.

 

Just Wed. of this week, my favorite import car mechanic "cleaned the PCV
valve and adjusted the idling" on my '89 Civic that had the exact same type
of problem. The vehicle now idles perfectly normal. He also mentioned the
following other things that can lead to this type of problem:
-Faulty fast idle valve
-Bad distributor that "can throw the timing off"
-Faulty IAC valve
-Faulty PCV valve
-Improper idle adjustment

J. Perry

 

Just Wed. of this week, my favorite import car mechanic "cleaned the PCV
valve and adjusted the idling" on my '89 Civic that had the exact same type
of problem. The vehicle now idles perfectly normal. He also mentioned the
following other things that can lead to this type of problem:
-Faulty fast idle valve
-Bad distributor that "can throw the timing off"
-Faulty IAC valve
-Faulty PCV valve
-Improper idle adjustment

J. Perry

 

Just Wed. of this week, my favorite import car mechanic "cleaned the PCV
valve and adjusted the idling" on my '89 Civic that had the exact same type
of problem. The vehicle now idles perfectly normal. He also mentioned the
following other things that can lead to this type of problem:
-Faulty fast idle valve
-Bad distributor that "can throw the timing off"
-Faulty IAC valve
-Faulty PCV valve
-Improper idle adjustment

J. Perry