swedrows

ok, so i have been searching for a while and can't find where the Idle Air Control Valve is located on the 2004 Acura TL....i have attached a picture of the replacement one i bought and wanted to install it. I thought it was located with the throttle body.....i removed the throttle body and it's not there?? any help please?

paperboy42190

iTrader: (7)

I didnt even know 3rd gen TL's had these lol

swedrows

i wasn't sure if they did or not, but when i was searching around the forums to figure out why my car was almost stalling during cold idling, several people mentioned cleaning the iacv and the throttle body....problem is i haven't been able to find anything on a iacv for a 2004 Acura TL except on the autozone website where they have the part listed specifically for it. that's why i bought it today thinking i would replace it and see if that would fix my problem....only i couldn't find anything in the repair manual as to the location of it :P

it still puzzles me that alot of people on the 3rd gen forum have mentioned cleaning their iacv...which apparently doesn't exist?? lol

pohljm

Perhaps its the PCV valve that your thinking of? that we have and that sometimes needs cleaning.

swedrows

no i specifically looked for IACV after reading about it from some posts by people on this forum when i did a search for rough idling. if you do a search for IACV you can see a lot of threads that have it mentioned so that's why i am confused as to if the TL actually has one. lots of members have posts specifically referring to it.

lleron

iTrader: (1)

I'm surprised about this as well. I thought the whole point of DBW was to get rid of crap like this, as the computer can electronically control how far the throttle body is open.

I know they can be a major pain on my 300zx... I'm curious to hear if the TL has one.

swedrows

so if the ecm controls how far the throttle body is open, can that possibly be the problem with my rough idling (and stalling) before the engine warms up? i was thinking that my ecm may be fried so i was going to look into grabbing one off ebay and seeing if that fixes the problem. i know it's not the spark plugs since i jst put in new ones in march

Hi speed

iTrader: (3)

I looked thru the 07 manual I have and there is no mention of it, I take that mean the 3G doesn't have one. I would return it to Autozone before that will not take it back.

libert69

iTrader: (7)

there is no iacv on the 3rd gen tl.

swedrows

yeah i went through the service manual a few times through all the diagrams and didn't find anything on it. time to keep diagnosing to figure out why my car idles rough and stalls sometimes before the engine warms up...

I hate cars

No IAC on a DBW car. Idle speed is controlled by the throttlebody and ignition timing. Throttle valve for large adjustments such as when the ac comes on or you shift from park to drive or high cold idle or when used as a dashpot to catch the idle when you rev and let off. The ignition timing is used for very small adjustments to give that super stable idle since it can react in miliseconds, quicker than a person is capable of noticing.

I hate cars

You might start with checking the coolant temp sensor if it only stalls when cold. First thing in the morning the CTS and air temp sensor should be very close to the same reading.

swedrows

finally figured it out and got it fixed...i bought a new egr valve and now the engine runs smoothly, no rough idle or idle drops when the engine is cold.

now i just need to figure out why i am getting a p2279 code constantly (i have no vacuum leaks, already checked, and did the idle relearn procedure twice).

I hate cars

If that's the intake air leak code, your bad EGR was the air leak. You just need to clear the code properly. Either that or you have a leak on the intake side of the EGR letting air in.

bluetl04

iTrader: (4)

How much did you pay for the egr valve?...OEM?

swedrows

i'll check the egr install and make sure the gasket is sealed properly since i only started getting the p2279 code after i installed a new egr valve, but i also removed the throttle body and cleaned that out with carb cleaner, so i am thinking that i should probably get a new throttle body gasket in case the old one is not sealing properly anymore. does that seem logical?

swedrows

my egr valve ended up costing somewhere around $45...it's an exact fit and i bought it new from AdvanceAutoParts and used an online coupon for $25 off of $75 (had to buy some carb cleaner as a filler to get to $75.

I hate cars

I'll check what it is that sets the code but most likely it compares throttle position to rpm and possibly long or short term fuel trims as a secondary as well to determine there's false air getting in the system as well. Did you happen to fire it up with the EGR removed? If the idle is normal and it doesn't try to shoot up right when you start it and go back down, it's probably something that just needs to be cleared and hopefully it won't come back.

bluetl04

iTrader: (4)

Is it possible for a egr valve to go bad without the check engine light coming on?

sauceja

iTrader: (2)

Just to clarify. If you say IACV valve then you are saying valve twice.

Just like saying PCV valve. Its either an IAC valve or an IACV.

And your new problem about air leak sounds like gasket failure. When you removed the TB did the gasket come off clean and was it hard/brittle? If so that could be your problem. As a recommendation you should always use a new gasket when removing TB and if not HondaBond is your friend.

What led you to look into the EGR for your problem of cold idle issues?

swedrows

when i pulled off the throttle body, the gasket stayed attached to the intake manifold all in one piece. i did not see any gasket residue or anything on the throttle body when i first pulled it off so i re-installed it after cleaning the throttle body. i'll have to order a new gasket since none of the auto parts stores around me have any in stock.

as of now, the code when away after i cleared it for the third time, but it has only been off for about a day so far.

as far as what led me to look into the EGR valve, it was one of the parts that was mentioned in a post when i was looking up rough idles along with the throttle body. i figured that if i was having issues only when the engine was cold, it had to be a part that got carbon buildup or whatever on it and wasn't able to function properly while the crud that was on it was cold and stiff.

I hate cars

IAC= Idle Air Control
PCV= Positive Crankcase Ventillation

So "PCV valve" would be correct.

sauceja

iTrader: (2)

Right on. Figured you had done some research. Just wasn't sure. But glad it fixed it for you.

And thanks IHC, i did forget about ventilation. I stand corrected.

TrustinHFDJ

Had the issue on my honda, kept turning off at idle, all you need is a 5 dollar spray or strong acid which will eat away at the build up.

Get the diagram from an acura dealership or check out the pdf

nfnsquared

I'm late to the situation, but for future reference, many folks have found pieces of carbon, etc, caught in the EGR valve and a simple blast of compressed air fixed it. Don't know if this would have helped in your situation or not.

For the P2279, the SM says to check the following for vacuum leaks:

PCV valve
PCV hose
Purge (PCS) line
Throttle Body
Intake Manifold
Brake Booster hose

If the code comes back, I'd suspect the throttle body gasket. (The SM procedure is to install a new gasket. Bolt torque spec is 16 ft-lbs).

Chad05TL

can a bad egr cause a cold rough idle? Someone told me once that the only way to tell if one is bad is by pressing on the inside diaphram. If it moves, you are ok.. If not, then replace. Many of these TLs have a cold rough idle. And I think its true that EGRs do operate heavily at a cold startup until the engine warms. because fuel mixture is richer. I think that probably why the old fashion cars used a manual choke. Because it Choaked off the air because it didnt need much air when its cold. Cold air is more dense. So, therefore choke it off. And then therefore the fuel mixture is richer

nfnsquared

Many have stated that the ECU purposely runs rich to warm up the cats quickly (for better emmissions) (and it certainly seems to do this as evidenced by the habitual rough cold idle of the 3G) but AFAIK there is no documentation in the OM or SM to support this.

Will Y.

Yes-- a bad EGR can cause a rough idle when the engine is cold and also when it's hot.

However, the car will throw a CEL after a few ignition cycles and rough idling with the bad EGR.

Chad05TL

All engines need to run richer at a cold start. It’s required of a combustion engine. Cold air is denser and it requires more choke to reduce the volume of air entering the cylinder. So the mixture becomes more rich.. or "balanced". Original cars had a manual choke. Even in the 60's they had manual chokes. My grandfather had a 60's Chevy van that had a manual choke. I remember him pushing and pulling that thing. As the engine got warm, he had to "disengage" the choke to let more air in, otherwise it would die. Because as the engine warmed, the opposite happened.. It needed more air.. Anyway, the rest is history. Carburetors had an automatic-manual choke. (if that makes sense) But then in the 80's, with fuel injection, chokes became electronic, with the invention of the IAC valve. The IAC on my IROC looked like a hole with a plunger where the plunger was operated by a little servo motor. The computer would open and close the choke by energizing the servo motor which was part of the IAC valve. Now I guess they can richen the mixture by adjusting the "open and close" duty cycle of an injector. ? not sure.. I have not inspected or studied how Acura achieves this same effect.

Chad05TL

If you want to know more about Duty Cycle, think of a switch that is open 50% of the time and closed 50% of the time. The Duty Cycle is .5. Fuel Injectors merely open and close. They get the squirting action from the fuel pump that pressurizes the line. So, all the ECM does is tell the injectors how long to stay open during the cycle.

http://en.wikipedia.org/wiki/Duty_cycle



On a separate note, notice that it's not good to run an engine at high rpms when it is cold. Because if the duration of the time the injector is open is longer when the engine is cold, hence a larger duty cycle, and if the engine is spinning faster and also requires more fuel, well, you may hit a cieling as to how much fuel you can pass and still have it run properly. This is why injector size and pressure is important so the ECM can have a full range of control at low and high rpms while the engine is cold or hot.

I hate cars

Chad can turn any thread into a babbling trainwreck. I've already explained how Acura "achieves this". It's with the DBW which would be the throttlebody for large idle corrections and ignition timing for fine idle adjustments.

A cold engine needs more air and more fuel than a warm engine and it needs a richer AF ratio. The choke on a carburetor is to add extra fuel, not to reduce airflow. It's the way carbs work, cover up the inlet and create a low pressure area and it goes rich. Carbureted cars needed a much richer mixture because of the wet manifold design and fuel fallout. We don't suffer that problem because port fuel injected cars have a dry manifold design so ours barely run rich at all. This can be achieved electronically instead of placing a choke over a Venturi in a carb.

You don't want high rpms on a cold engine because the oil is cold and clearances are still closing up. You don't run out of fuel lol. As an "engineer" you might want to remember the other factor in fuel consumption, load.

EGR is never supposed to operate at idle chad. Exhaust gas can't be reburned. It's fed into the intake as an inert gas to cool combustion temps and reduce NOx emissions. The ECU will bump up the timing when it commands EGR and in some cases open the the throttle a little more to make up for the dead space taken up and the resulting power loss by the exhaust gas. If the valve is letting exhaust by at idle because of a leak, the ECU has no way of knowing and the idle suffers.

Lets not dumb this down anymore chad, it takes a while to correct you from my phone.

Chad05TL

Your a trip. Full of hate. Anyway, most engines just dont rev well when its cold. I suspect it has to do with fuel but cold oil could be a contributor too.

But if you cover the carburator like you said, it will go richer. Same principle as what I said.

Also, you just said we have a dry manifold and to richen it up, they can do it electronically. I said the same thing. Fuel injector duty cycle, or fuel pressure and fuel injector size are all ways to do it, but the fuel injector duty cycle is adjustible.

But as far as an EGR not running at idle, you are correct. I just verified they dont run at idle UNLESS there is a problem. If the EGR runs at idle, then stumbling or even stalling can occur per this webpage. However, even though I have a slightly rough idle when its cold, and that does indcate something is probably not right, it may not be a result from the EGR. So I'm now leaning toward it not being the EGR problem.

Either way, you still need to change your bad attitude. It's not productive and it just shows how ugly you are.

Chad05TL

Injector Duty cycle will allow a richer fuel mixture.

Read up buddy..
http://docinjector.com/info1.htm

I hate cars

Who are you arguing with because I most certainly said nothing about injector duty cycle. Of course increasing injector pulse width and/or DC delivers more fuel.... But not like you're thinking. Raise the rpms and you need to increase DC while keeping PW the same to maintain the SAME AF ratio. Increasing PW with all else being the same may or may not richen it depending on volumetric efficiency at a given rpm.

With that said, DC alone won't ALWAYS richen things because as rpms rise DC must be increased to maintain the same AF.

Anything else chad? Wiki will only get you so far.

Chad05TL

you just like to argue

Chad05TL

Anyway.... this part is likely the "Bypass Valve". It lets more air into the intake under certain conditions , like heavy load, from what I have read. Several sellers online call this the Idle air control valve. Officially, I think it is the Bypass Valve but it does act similar to a IAC valve by letting in additional air.
Acura part number 17150-RCA-A01
Part number listed on the valve: Denso 012010-1010

Chad05TL

Update: The info I posted above is for the2005 TL. I think the picture you posted is actually 1st or 2nd gen TL. Idle air control valve, which is mounted on the throttle body.

Like all these
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