DIY removal & cleaning of IAC

[mr2crazed]

Tried cleaning the throttle body with Sea Foam Deep Creep and still had difficulty starting the car when the engine was cold. So I decided to remove my IAC (idle air control valve) on my 1994 Camry with the I4 (5SFE) to clean out all the carbon. Not really seeing any “how to” processes, I decided to document my process with pictures. It took me a total of 1 – 1.5 hrs to do it but your results may vary. Make sure the car is cold as you’ll be disconnecting some coolant lines.
I ordered some gaskets from Toyota, the IAC gasket wasn’t available anywhere else. Here are the part numbers and prices I paid. You may not need to replace them but I decided it was worth it. Also in my list are the items I used for the procedure.
22271-74022 Throttle Body Gasket $5.54
22215-74400 IAC gasket $1.72
(4) M5x16 hex bolts and lock washers to replace the 4 phillips screws that may or may not strip when removing them from the IAC.
Sea Foam Deep Creep (or whatever your favorite brand sensor safe cleaner would be)
Throttle body cleaner
10mm & 12mm sockets
Torque wrench
Phillips screwdriver
Pliers, needle nose and standard
Multimeter to measure resistance

Step 1. Remove the snorkel from the air filter to the throttle body. You’ll need to disconnect the air temp sensor and pull a vacuum line close to the throttle body.

Step 2. You want to make sure the valve itself is good by checking the resistance and confirming it’s within specifications (19-23ohms). Remove the connector from the IAC and place a probe on the center pin and check the resistance by placing the other probe on the other 2 pins, see photos.
If it’s out of spec., the IAC will need to be replaced. If within spec., proceed with cleaning.




Step 3. Disconnect the TPS, EGR, and Vacuum sensors as illustrated in the following photos and move harness to the side to give clearance.



Step 4. Remove the large EVAP hose from the left side of the throttle body and the 3 vacuum lines from the top of the throttle body. These simply pull off, no clamps.



Step 5. Underneath the throttle body are 3 tubes going into it. The middle one is a large vacuum line that also simply pulls off, see photo.


Step 6. Now the fun begins, well at least it did for me. The other remaining tubes are coolant lines and are held in place with pinch clamps. I labeled the hose at the rear with an R so I’d know where it should go when reassembling. Slide the clamps down on each hose where it mounts onto the IAC. You may have the break the seal by carefully grabbing it with pliers and rotating. I actually had to remove the throttle body from the intake for better access. Have a small bucket or cup to catch the coolant. Only a little (about a cup) will come out. I removed the radiator cap prior to relieve system pressure.


Step 7. I left the accelerator cables attached and removed the throttle body. Flip it over to have access to the 4 phillips screws holding the IAC. These screws were very tight and other people have had theirs strip which was why I purchased replacement hex head bolts, just in case. Then remove the IAC and you’ll see the carbon build up on the throttle body and IAC itself. You’ll see in my second photo, me pointing to the sticking shutter inside the IAC.



Step 8. Clean up that IAC. I used Sea Foam Deep Creep since it was sensor safe. Once it’s good and clean the shutter should rotate smoothly. Then used throttle body cleaner to clean the back side of the throttle body and the passages for the IAC.


Step 9. Install a new IAC gasket and reattach it to the throttle body with either the old screws or the new hex head bolts with locking washers. Then reattach the throttle body to the intake and torque the bolts to 14ft lbs.

Step 10. Reconnect the coolant and vacuum lines and all the electrical connections from the previous steps. Install the filter to intake tube and start it up. There could be a little smoke upon start up from any residual Sea Foam so don’t be alarmed, although mine didn’t. Take it for a drive and enjoy your success. Get home, clean up, and crack open your favorite beverage

[peshwa]

Comes at the right time! Thanks a bunch dude... Why didnt you pull out the throttle body and clean it out proper?

[AliRazoR]

thanks a lot

[mr2crazed]

Originally Posted by peshwa

Comes at the right time! Thanks a bunch dude... Why didnt you pull out the throttle body and clean it out proper?

I cleaned the throttle body from the backside when I had it flipped over. It was so gummed up it was almost like tar !!!

[peshwa]

great...! Any noticeable improvements?

[73sport]

Hey, Nice write up!

I would like to add the following:

For continued smooth operation, the rotary valve needs a light application of grease to the shafts contact points. I used air to blow it between the valve and valve body and then cleaned the excess off. Without the grease it will likely stick later. A very light duty synthetic grease with good cold condition properties is best. I can't find what yoda specified for the PN.


You can also measure the continuity of the terminals. Just to make sure the part is good and test it with a battery to make sure it opens and closes. Suggest you see the FSM for terminal pin-outs.

Using an ohmmeter, measure the resistance between terminal +B and other terminals (RSC, RSO). Resistance: 19.3 – 22.3ohms at 20°C (68°F) If resistance is not as specified, replace the IAC valve. Same value for both I4 and V6.

With a 12vdc source; connect the positive (+) lead from the battery to terminal +B and negative (–) lead to terminal RSC, and check that the valve is closed. If operation is not as specified, replace the IAC valve.

With a 12vdc source; Connect the positive (+) lead from the battery to terminal +B and negative (–) lead to terminal RSO, and check that the valve is open. If operation is not as specified, replace the IAC valve.

[TOYOPARTSMAN]

Nice write up, very detailed, Pictures are really nice.

[73sport]

Originally Posted by AliRazoR

the unit of resistance is ohm NOT (W)watt

Blame the FSM . . . . but I'll happily correct that detail!

Actually I didn't go back and look at the FSM, but it could have been a software interpretation of the Ohms symbol as I did a copy/paste so Adobe, to clipboard, to InterNetz. . .

EDIT: FSM is correct, its a software interpretation issue!
Repeat paste => 19.3 – 22.3W at 20°C (68°F) << wtf??

Here is a copy paste from another ohms. In this case it was a "null input resulting in a square invisible block after 39. >> "33 – 39 at 20C (68F)" So, Note to self, always pay attention.

[mr2crazed]

Originally Posted by peshwa

great...! Any noticeable improvements?

So far so good. It's been starting up fine in the mornings.

[adalex]

I vote for sticky!

[LynchburgCSI]

^ It's on my to do list!

[fenixus]

great DIY! nice pics!

[JimBowNut]

Well got that project finished with ease. Appreciate help and pics in your write up!
Did notice that the funk in the TB and IAC would not dissolve with the Sea Foam Deep Creep. Ended up using the tried & true friend 'GUMOUT'. Did let everything dry out before install though. Man !, The back side of TB looked like my wood burning stove on the inside ! And does anybody ever clean the intake ? It was Horrible !

[brianjrealtor]

I have a 1993 Camry and this post came in handy...big time!

I ended up at a pick/pull salvage yard and found an IAC valve ($20) that spec'd out at 22.1 Ohms for the open lead and 22.3 for the close lead...I soaked it overnight in the deep creep before cleaning and testing for proper operation the next day. i thought it wouldn't work, but i tested it and found the valve would move back and forth...

a few things to note that will help others out....

1) it took me 4 hours time to do this job right. I don't rush jobs like this one. But keep in mind, the carbon buildup on the TB and the valve takes time to remove on these old cars, but is worth the time invested with the deep creep and a toothbrush.

2) IMPORTANT! I bought an impact tool to loosen the IAC valve phillips head screws. I didn't want to take any chances. I sprayed the deep creep first, let sit for 30 minutes and popped the screws loose easily with a whack of the hammer. to brace the TB for the hammer whack, I had a block of wood underneath on the garage floor with rags in between to prevent scratches. Be sure to brace it as to not damage the TP sensor or vacuum leads. Use the same force as driving a nail into wood. the bolts loosened with a good whack apiece and were perfect to reuse afterwards, no screws damage! the tool cost me $8 at a specialty hardware store I use (Harbour Freight), but if you search, you can call around and find one on the cheap. well worth it!!

2) The Sea foam deep creep is awesome. it seems to penetrate deeper than TB cleaner or anything else. you just have to spray liberally and let it sink in for about 10-15 minutes before scrubbing. once you use the toothbrush and scrub, the carbon lifts off easily

3) I used pipe cleaners to really work around the valve shutter and clean more internally.

4) I tested the IAC valve for operation with a 9V battery instead of the car battery. it's easier and safer to me, and the valve moves back and forth easily with 9 volts..


these are my 2 cents worth...hope it helps!!

the car now idles smooth, and accelerates smoother and faster than before.

[fenixus]

will be doing this finally on tomorrow morning.

time has come I am fed up with variable idle speed on wife's 5s-fe, drives me nuts, I guess the rough cleaning through TB opening fixed it more or less and it still is dirty inside. will see tomorrow, wish me luck.

bought new M5x0.8x16mm bolts and M5 washers to replace the 4 old Philips screws (can't believe Toyota used screws!), in case I break/bend/damage them upon removal. have new gaskets handy for TB & IAC, just need a bit of luck to do this right, once and for all