Idle air valve not working

Hi,

You have done a lot. The one thing I noticed you didn't mention was checking for engine vacuum leaks. That can cause an idle issue. Also, I noted you check for codes, so I suspect you have a scanner. If it is a live data scanner, can you let me know what the fuel trims are. I would specifically like to know the short term fuel trims.

Also, by any chance did you confirm there is nothing blocking the air passage allowing air to enter the engine via the IAC? Note in the pic below how air flows.

I'm not sure if you need it, but here is a link that explains how to check for a vacuum leak:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know.
Joe

I added 3 data screenshots from idle 1500 and 2500 rpm. Short term trim bounces a lot but generally at idle it's plus minus 2, long term is locked on -14.8 at idle but when driving is around 0, at higher no load rpm it sits at -9.4 steady. O2 sensor 1 in header bounces .1 to .8, sensor 2 after cat is 0 to .1 whenndriving. Steady 0 at idle. I did hunt for vacuum leaks, couldn't find any. Any tricks to try on that? MAP seems low enough. I put some vacuum to EGR valve at idle and engine chokes instantly. If I pull a vacuum line and leak air the idle shoots up to 1200. How can I test EGR for leaks?
I took throttle body off completely when I changed IAC and cleaned completely all passages were open.

And Thank you for helping!

One more sensor, throttle position shows 10.2 at idle 12.5 at 1500 and 14 at 2500 no load.

The car is old, I'd like to get another year or two out of it, I'm under no illusion that it should run perfectly, I can live with the somewhat rough idle , but the lack of proper cold start fast idle here in Minnesota is the big issue. It barely starts on days below 10F, choking and needing me to give it gas to keep running, and it's never done that before. I just can't figure out what I could have done to cause it by changing timing belt. I have done that job before two times with no issues.

I looked through the pics you attached. Was the engine warm when you did the test? I noted the engine at 208°F and the air intake at 55°F. Just curious. As far as the egr leaking, based on fuel trims, I would say the problem isn't a vacuum leak. However, here are the directions for testing the EGR system. The attached pics correlate with the directions.
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1999 Toyota Camry CE Sedan L4-2164cc 2.2L DOHC (5S-FE) MFI
Component Tests and General Diagnostics
Vehicle Powertrain Management Emission Control Systems Exhaust Gas Recirculation EGR Valve Testing and Inspection Component Tests and General Diagnostics
COMPONENT TESTS AND GENERAL DIAGNOSTICS
1. INSPECT EGR SYSTEM


pic 1

a. Inspect and clean the filter in the EGR vacuum modulator.
1. Remove the cap and filter.
2. Check the filter for contamination or damage.
3. Using compressed air, clean the filter.
4. Reinstall the filter and cap.

HINT: Install the filter with the coarser surface facing the atmospheric side (outward).

pic 2

b. Using a 3-way connector, connect a vacuum gauge to the hose between the EGR valve and VSV.
c. Inspect seating of the EGR valve.
Start the engine and check that the engine starts and runs at idle.


pic 3

d. Using SST, connect terminals TE1 and E1 of the DLC1.
SST 09843-18020

e. Inspect the VSV operation with the cold engine.
1. The engine coolant temperature should be below 55° C (131° F).
2. Check that the vacuum gauge indicates zero at 2,500 rpm.


pic 4

f. Inspect the operation of the VSV and EGR vacuum modulator with the hot engine.
1. Warm up the engine to above 60° C (140° F).
2. Check that the vacuum gauge indicates low vacuum at 2,500 rpm.
3. Disconnect the vacuum hose port R of the EGR vacuum modulator and connect port R directly to the intake manifold with another hose.
4. Check that the vacuum gauge indicates high vacuum at 2,500 rpm.

HINT: As a large amount of exhaust gas enters, the engine will misfire slightly.

g. Remove the vacuum gauge, and reconnect the vacuum hoses to the proper locations.


pic 5

h. Inspect the EGR valve.
1. Apply vacuum directly to the EGR valve with the engine idling.
2. Check that the engine runs rough or dies.
3. Reconnect the vacuum hoses to the proper locations.

HINT: As exhaust gas is increasingly recirculated, the engine will start to misfire.

i. Remove the SST from the DLC1.
SST 09843-18020

2. INSPECT EGR VACUUM MODULATOR


pic 6

a. Disconnect the vacuum hoses from ports P, Q and R of the EGR vacuum modulator.
b. Block ports P and R with your finger.
c. Blow air into port Q, and check that the air passes through to the air filter side freely.


pic 7

d. Start the engine, and maintain speed at 2,500 rpm.
e. Repeat the above test. Check that there is a strong resistance to air flow.
f. Reconnect the vacuum hoses to the proper locations.


pic 8

3. INSPECT EGR VALVE
a. Remove the EGR valve.
1. Disconnect the 2 vacuum hoses from the EGR valve.
2. Remove the 2 bolts 2 nuts, EGR valve and 2 gaskets.
b. Check the EGR valve for sticking and heavy carbon deposits.
If a problem is found, replace the valve.
c. Reinstall the EGR valve.
1. Temporarily 2 new gasket and the EGR valve with the 2 nuts and 2 bolts.
2. Tighten the nuts.
Torque: 13.3 N.m (136 kgf.cm, 10 ft.lbf)
3. Tighten the bolts.
Torque: 10 N.m (102 kgf.cm, 7 ft.lbf)
4. Connect the 2 vacuum hoses to the EGR valve.

4. INSPECT VSV FOR EGR

__________________________________________________

Let me know if this helps.

Joe

Yes the car was warm. Idling in my driveway for quite awhile. Fans were cycling as expected, they cycle on at 212F. Thermostat is good. Going down the road the temp is a steady 185F. The only time I ever hear the fans run is with extended idling. I will do EGR test tonight.

The fans sound normal. When you are moving in cold temps, there is no need for them to run. Let me know about the test results.

Take care,
Joe

EGR checks out okay. Any other ideas?

Are you sure there are no vacuum leaks, unplugged sensors, or leaks?

Joe

First off let me say I appreciate your assistance. No unplugged sensors, no vacuum leaks that i can find. If I pull a vac hose off the idle shoots up higher. To me it seems starved for air. Why does the IAC valve test fail? You said based on my fuel trims you didn't suspect vac leak any more. Still seems like the IAC valve is just not working. Maybe I got a bad part. . I don't know what else to think. Today it was about 10 below and it was stalling at corners and really surging at idle. Maybe I'll donate it for the tax break :)

Hi,

It is possible the part is faulty. The looping you described is typical for a bad IAC. I asked again about vacuum, because things change. Is the IAC under warranty?

It was a bad "new" IAC. I'm so mad. I hunted this beast forever. Finally last night I cleaned the heck out of the original IAC and put it back on. Runs fine. Fast idle is back when cold and idles down to about 750 once warm.

So here's what I assume happened: My IAC was dirty and had limited motion. Battery disconnect for timing belt job reset ECU and it was not able to learn idle again with dirty IAC. So my first diagnosis was correct. However since I just replaced the IAC and assumed then that it wasn't the fix because it didn't help, the wild goose chase started. I should have just cleaned it from the get go. I did try spraying carburetor cleaner in it but didn't try too hard since it was only $35.00 on eBay. Probably a bad Chinese knock off.

Thanks for the help.

Wow! I'm glad you got it fixed. I learned a long time ago that all parts are not equal. LOL At this point, and because I don't want to do the job twice and have an upset customer, I only accept certain aftermarket brands. People are importing parts from overseas for next to nothing, selling them cheap (and still making a ton of money) and the consumer is the victim.

Regardless, it's good to hear you got it taken care of. Please feel free to come back anytime you have questions or need anything.

Take care,
Joe