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Removing Idle Air Control valve?

The suck test is basically a test of the valve inside the EGR. When the car idles, its open, when your accelerating, its closed. The test is to determine if the valve is seating properly and intact. When you suck on it (i.e. create a vacuum), it closes the valve while your cars idling and causes it to stumble and/or stall out.

Good thing no one looks in these threads Ian, or we might have a bad case of edit on that last post.
 
KerryKool said:
The suck test is basically a test of the valve inside the EGR. When the car idles, its open, when your accelerating, its closed. The test is to determine if the valve is seating properly and intact. When you suck on it (i.e. create a vacuum), it closes the valve while your cars idling and causes it to stumble and/or stall out.

Good thing no one looks in these threads Ian, or we might have a bad case of edit on that last post.
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you have it backwards. the valve is closed at all times except for under cruise/light throttle conditions when the PCM commands it to open. the suck test opens the valve when it should be closed which dilutes (the actual A/F mixture is still correct as it does not lean out the mixture since exhaust gas is inert and thus noncombustible) the mixture and causes the car to stumble.
 
Suck Test 101

Suck Test 101

This is quite an education about Contour "suck tests" and yes, it not only sounds weird, but kinky too!

But I think I'm getting it.

You put your lips on the hose going to the small vacuum fitting on the EGR valve. Or do you add your own clean hose?

Then, with the car idling, you suck on the hose attached to the EGR vacuum fitting. That should cause the EGR valve to open which dilutes the fuel charge and stalls or causes the engine to stumble.

Is that it?

Maybe you have use a longer clean hose to fit on the EGR valve for the suck test. Otherwise I don't see how you could stick your face into that cramped engine compartment. Am I right on that?

My new IAC should be here today and I'll put that baby in first.
 
cetroutt said:
i would have just cleaned the old IAC before buying a new one.
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And you'd be right to do that too (see my PSPS/Low Idle thread).

BUT buying the new IAC stimulated me to start working on the problem again. Before that I just thought about doing it but after ordering the part I dug right in. Plus I figured that with all the work taking the old IAC out, I didn't want to redo it if the old one was truly bad. As it turns out the low idle might be related to broken wires and a disconnected PSPS. At least that is my new working theory. (Fingers crossed).
 
yeah i saw that, and what you're saying about your pressure switch does make sense, hope you get it figured out.
 
Low idle persists

Low idle persists

cetroutt said:
yeah i saw that, and what you're saying about your pressure switch does make sense, hope you get it figured out.
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Thanks, but it isn''t figured out yet.

Yesterday I soldered the PSPS back into the wiring harness and took a ride. The idle is somewhat improved but still NOT right.

In park and neutral it "almost" seems normal (kind of low but runs), but in park with the brake on the car starts to "chug" and even rock a little because the idle is still too low.

Looks like I'm back to square one and there is more than one problem affecting the idle.

Today I'll take it out on the highway and see what codes come up.

I also have a nice new IAC to try.

Previously I did get 02 and EGR codes.

Vacuum leak? I looked, but the hoses are difficult to trace and inspect.

What is the #1 cause of low idle condition?

Thanks!
 
Follow the pcv hose back to the intake manifold and check closely where it makes a sharp 90 degree bend, right before going into the manifold. That right there is the number one cause of what you're describing. The hose will likely feel soft and dryrotted.
 
mcgarvey said:
Follow the pcv hose back to the intake manifold and check closely where it makes a sharp 90 degree bend, right before going into the manifold. That right there is the number one cause of what you're describing. The hose will likely feel soft and dryrotted.
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what he said. and if i missed it somewhere when did you last replace the PCV? i've noticed a world of improvement in mine since i cleaned my IAC, and replaced the PCV, and timing belt.
 
Thanks to both of you.

I will inspect the PCV hose for damage. Also, the PCV itself is old and so it the IAC and the EGR.

Probably I should first replace the PCV (I have a new one) and also inspect/replace the hose. If that doesn't solve the problem, then tackle the IAC (which I also have a new one).

Thanks again.
 
Finding PCV to Intake Manifold Connection?

Finding PCV to Intake Manifold Connection?

Do I need to remove any components to find the PCV hose to intake manifold connection? I ask because I'm having a hard time finding it. I located two vacuum hoses with right angle bends on the back of the intake manifold next to the firewall, but these turned out to go to the EGR and Fuel Pressure Regulator. They appear to be in good condition.

Just where is the PCV hose to intake manifold connection located? Which side of the intake manifold? Can you find it without taking other stuff off?

I also took the front heat shield off and can see the PCV pipe and oil separator behind the exhaust manifold. Didn't proceed any further today but tried to figure out vacuum and PCV line locations. Added lots of notes to my Haynes book...

Thanks!
 
the PCV connection to the intake manifold is on the side of the manifold. look down between the EGR valve and the coil pack and you should see it. its actually a T style connection as thats where the EVAP purge system comes in as well.
 
I'll put the car up on ramps again and look from underneath because yesterday I couldn't see the PCV to manifold junction from the top side even with a better idea of where it is.

It looks like a metal tube coming out of the PCV itself but then it must connect to a rubber hose near the manifold if that's what becomes rotten. I doubt that has ever been replaced.

Thanks again.
 
i know its not the greatest picture but hopefully it will help.

circled is the metal tube from the PCV and the arrow points to where it connects to the side of the manifold. right next to the head.
PCV-manifold.jpg
 
striker2 said:
the PCV connection to the intake manifold is on the side of the manifold. look down between the EGR valve and the coil pack and you should see it. its actually a T style connection as thats where the EVAP purge system comes in as well.
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This seems correct and I "think" that I found it. From the T connection does the PCV line goes straight down at first? Does the EVAP purge line go towards the firewall? That's the line I'm looking at. Way up towards the top between the coil pack and the EGR.

Which line has the sharp bend that goes rotten? The one from the T fitting to the PCV or the one from the T fitting to the EVAP?

The line from the T to the EVAP seems okay but the line to the PCV is down out of sight. The T fitting is right near where the line enters the intake manifold.

Does this sound like the correct line from PCV valve to the intake manifold?

I am determined to fix this thing.

Thanks!
 
yup, that sounds like you have found the correct line(s). the EVAP side doesnt normally have issues, unless it gets kinked and cracks.
 
Thanks. The EVAP line from the T looks fine.

Yesterday I sprayed some carb cleaner around the PCV "T" fitting and hoses with the motor running. There was no change in idle speed. Does that mean they are okay?

Still, I can't visually see or inspect the hose from the T to the PCV valve and whether it is bad or not. Maybe I'll try to replace the PCV valve next since I already have the heat shield off.

Looking back thru the service records for this Contour I don't see that the PCV or the EGR were ever replaced. No mention of vacuum hose replacement either. But around 30,000 miles ago one record reported "rough idle" and the injectors were cleaned. I wonder if that worked and if that's the problem again?
 
I've been having a throttle hang issue with my '98 Contour with the Zetech (after releasing accelerator, car will continue to throttle for about 1-3 seconds). I had Firestone Service Center run the codes and the mechanic said it's most likely the Idle Air Control Valve. So I've been prcing the parts stores online for a new IAC. What is with the wide range of prices I am finding? Normally all the parts stores are within $10 or so on a given part, but I've found NAPA asking $234, Autozone asking $67, and several other stores all around $110. All with 1 year warranty. Presumably, they'll all function the same, right? What's with the wide range of $?
 
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