Whats up everyone.

So I have been having this idle issue before and after I changed my clutch. When I am idling the revs bounce from 500 to about 2500 consistently. When I start to accelerate it begins to go away. But when I come to a stop it starts doing it again. I just replaced the idle air control valve underneath the throttle thinking thats the problem and it wasn't. I turned on my A/C and it went away initially but than when I started to drive it came back. I thought it might be the TPS bc when we unplugged it, it stopped the idling bouncing and just rev'd at 500. Does anyone have any ideas what this could be before I commit to taking this to the dealer because it stumped myself and my uncle.

 

When you replaced the IACV, did you also replace the gasket? Did you thoroughly bleed the coolant system?

Have you checked for vacuum leaks with an aerosol?

 

I replaced the iac gasket with a brand new one. I checked for any vaccum leaks around my intake manifold, any hose coming off of the intake, and hose around the throttle body and iac. I have not bled my coolant lines but will give that a try. I talked to one of the techs at acura, he seems to think that I need to reset my ecu engine codes.

 

It could be the Power Steering Pressure Switch or it's connector/wire, that causes similar symptoms.

Your new IAC could also be defective right from the dealer.

 

If my Idle is bouncing but not throwing any codes.. could it be a vacuum leak?

 

when I had a vacuum leak it threw a code. If you plug the IAC hole inside the TB while the car is on, do the revs stabilize? If so, it's the IACV. Did you accidentally swap the IACV connector with the TPS?

 

If I let it idle up and down too long it will stabilize at like 2000 rpms and then throw a P0505 Code. Ill check the IAC hole in the throttle here in a little bit. Is there only one hole in the TB? As for the connectors. I thought they only wen on one way but if not I will give that a try also! I Got an appointment to take it to the stealership bc I just don't have the time to diagnosis it further like I want to

 

I meant MAP and TPS. I believe there's only 1 hole before the plate and it's right where the IAC sits.

 

tried to take a quick look on my way out to the dealer and don't think it is a mix up on the switches. Just dropped it off and going to have them diagnosis it and give me an estimate. I know I can fix it on my own just need help identifying the cause. But they gave me a TLX as a rental, I gotta say it was pretty bad ass . Of course its not the CL! but man that thing is surprisingly fun to drive

 

one of the easier things to do is just spray carb cleaner over the ports or where you suspect a leak is. the liquid will patch the hole temporarily (~2 sec) and you can see if the idle stabilizes over that time.

 

Yea I should have taken a little bit longer to do that, but I spent a couple mins testing the ports on the manifold, and any off the TB or intake. I have a IM Spacer by P2R, I even sprayed around that to see if there was a leak somewhere under the manifold

 

OK everyone my idle surge is back.

I dove the car 40 miles total on Saturday. Then took my girlfriend out to dinner and dropped off my car with the valet and went inside. I come back out after dinner and valet pulls my car around and guess what, idle is surging again and I have a Idle air control valve code. I had originally bled my coolant and thought I had an air bubble in the system, because once it was bled it was fine. It has been driving for 3 months with no problem and I haven't touched anything!

So I am going to try and find the problem again tonight. Here is my check list.

1. clean Idle air control valve again ( was replaced 3 months ago)
2. check again for any vacuum leaks with carb cleaner
3. Bleed the coolant system again for air bubbles
4 Remove any ports the the vacuum hoses connect to and make sure there is no silicone clogging them


Does any one else have any recommendations for this kind of problem?

 

did you ever try plugging the IAC hole in the TB? That should tell you if it's the IAC or a vac leak.

 

Check your EGR valve too.. I had idle issues on my old Accord and 3g TL and the EGR sometimes has a piece of stuck carbon at the valve that causes weird idle issues..

 

No I never did because it went away after bleeding the coolant system. I will deff look into that tonight as well. So do i need to just remove the hose and block off one side and see if the idle changes?

Yea I am going to take a look at that again tonight. I would think being that the part is only a few months old that wouldn't be the problem but who knows at this point I saw a video this morning from a Toyota 4runner and the coolant port off the throttle body was clogged with silicone and once he cleaned it it was fine. So I am going to remove all the ports and make sure they are clean and not blocked

 

detach your intake from the TB and plug the large hole before the throttle plate with your finger. If the rev stabilize then it's the IAC. If not vac leak.

 

Sounds good gnuts i'll give it a try as soon as I get home

 

Ok gnuts .. update.. I removed the intake and started the car.. with the hole unplugged the idle rose to about 1200-1400rpms. Once I plugged the hole with my fingers the idle dropped down to about 700-900 rpms and sat there perfectly...

So this means my IACV is the problem?

 

Looks like it. Have you cleaned out the intake manifold of crud ever? Seems like maybe a piece got lodged in the IAC.

 

Yea I have cleaned out the manifold multiple times along with the egr port and everything around the plenum gasket. I have the Idle Air Control Valve completely removed from the throttle at this point. Should I just try and clean the little piston that moves in it, and if that doesnt work does that mean that it could be the sensor that is malfunctioning?

 

By any chance do we have a cold fast idle valve as well? or just IACV? I saw on the Honda Forums that that could be the culprit also, if its not IACV or air in the system

 

OK so update.


I couldn't return the IACV so I cleaned it out with carb cleaner I cleaned the throttle body, the plenum, and the EGR. I then started the car and it was still surging once it got to operating temperature. I then disconnected the battery to reset the computer and the code. I started it and it surged twice and then looked like it found the right idle. I let it sit there idling perfectly for about 10 minutes. I reved it ONCE and it immediately started surging again..

 

maybe the TPS is going bad...just a thought

 

Yea I thought about that also.. This is where this problem stands right now.

I think this was a multiple issue problem and not just one source. I replaced my Coolant temp sensor and my Map. The problem got a little better but not fixed. So I was stumped. I opened up my manifold top plate to make sure I didnt install the gasket upside down and noticed I had alot of oil build up underneath.

This with a combination of the there not being an issue until I touched the throttle, prompted me to check my PCV valve. Sure enough it was torched as oil was getting into the sensor an burning. I replaced it for $3 and still didnt fix it.

I cleaned my egr port on the plenum 2 days ago as it was pretty dirty. Checked it again when I had the top plate off, and holy crap it had CAKED up just after 2 DAYS!

So at this point I think it is my EGR valve not closing all the way and too much exhaust gas is getting into my manifold. This would make sense because I noticed I am getting what sounds like a misfire but on the exhaust side of the engine. Like unburden gas is getting through and detonating across the headers. So it has to be the EGR valve.

Going to try and clean it tonight. but might just clean the ports on the engine and replace the valve entirely.

If that doesnt do it than the last thing I can think it would be is the TPS and I would probably just replace the TB set up and not deal with just installing the TPS unless it is easier than it sounds

 

Just to confirm, after you replaced the IACV, you 'burped' the system to get rid of air right?

 

Correct. I bled the system several times. I thought I had air in the system a couple months ago because after I bled the system the problem went away. Looks like that was just coincidence, because it is back now

 

Ok so I cleaned my EGR port under my top plate and replaced my EGR valve with a brand new one. I am officially stumped. I HAS to be a vacuum leak somewhere but I just cant find it.

I even loosened my throttle cable for the chance that maybe my throttle wasn't closing all the way and that wasn't it...

Gonna spend some time this weekend trying to hunt this vacuum leak down

 

Update.. So I checked all my sensors and all my vaccum lines around the Manifold/ Throttle and no dice. It looks like I have a leak somewhere below the manifold. I am going to replace my gasket between my runners and my engine and my manifold gasket and my plenum gasket and inspecting all the parts while I am down there ..


We will see

 

Check how your grounds are looking while you in there. Worth a shot.

 

So update again.. Idk if anyone is still reading this but.. took the plenum apart and got to the bolts holding the manifold down to the runners and holy crap.. they were all loose! I didn't have a torque wrench when I tightened them back down after taking off the spacer so they were all loose to the point I just used my hand to unscrew them.

So I am going to assume that this would be the culprit to my vacuum leak. So at this point I am going to replace my runner/engine gasket, my manifold gasket and my plenum gasket. Because they look SHOT!

Last night I broke everything down, removed the fuel injectors and was going to start unbolting the runners but it looks like the power steering pump is blocking the final bolt on the front and back runner. Anyone ever taken their runners off? or have any tips? Do I need to remove the PS pump?

I have the Helms manual but can't find it anywhere in the book. It has to be in there though!


Thanks in advance!

 

I ported my runners last summer and took them on and off a few times, since I tried reusing my head-runner gasket which caused a vac leak.

If I remember you need some extensions and swivel bits to get them in there. I sprayed all the bolts a few times with some PB blaster. The rear passenger bolt you have to hold some wiring out of the way and you can get it on there. I didn't remove anything major to get at the bolts though.

If you're not porting the runners or anything, why remove them? They're not causing your leak, the manifold gasket is.

 

Thanks Gnuts! You dont think the gasket between the engine and the runners would have been affected as well because of the massive leak? If I dont have to remove them then I definitely wont! I wasnt sure if this was a better safe then sorry situation

 

no it should be fine. Those runners are on there crazy tight. When removing them for the first time, you have to tap them with a mallet to break them loose.

 

would you replace the intake manifold top plate gasket also? It is pretty much brand new but looks pretty burnt already...

 

Might as well while your in there, brand new gaskets FTW

 

Well put everything back together. torqued down everything to spec all new gaskets (Runners up) in.. Still surging ... I have no idea now .. gonna take another look this weekend

 

check over the manifold again to make sure all your hoses are connected. is the throttle body gasket new? get some carb cleaner, start the car and spray it on various parts. If the revs stabilize you've pinpointed your vac leak.
this is a longshot, but I've heard of guys with cracked runners from torquing the manifold too tight.

 

Yea I will give the carb cleaner a shot.. New throttle body gasket, plenum gasket and top plate gasket ..but man I have heard that too and I'm hoping that isnt the case!

 

Can a faulty fan switch cause a problem like this? I know faulty coolant temp can but could the fan switch also?

 

Anyone one know what the little PVC looking part it that is pushed down through the bracket holding all the clips to the injectors? Its on the front and the back and has a vacuum line connected to it..


Also how the hell did you get the bolts holding the runners down, off?? There is like no space to get my socket on it bc it is too close to the runner, and if I use and open ended 12mm it starts to strip bc I cant get a good grip ..