I just installed the 2009 TL SH-AWD Manifold and have run into the surging idle issue. The car idles at 2000 rpm for 15-30 seconds and then surges between 1000-2000 rpms. I've done multiple searches with solutions ranging from changing the gasket between the manifold and intake runners and plugging the IACV. I believe there was a thread directly on this issue but haven't found it. If someone knows the thread link, pls send it, otherwise I welcome suggestions.

Thanks!

 

no CELs? Try a diagnostic scan and see if there are any misfires. Might be a simple fix.

 

Try drive it a bit and make sure you reset ecu before you do that.

 

Spray carb cleaner around all gaskets to check for leaks.

 

No CELs, car drives great except under 2k rpm. I'll try the carb cleaner and reset. I'm hoping it's the gasket between the manifold and the intake runners. Does it need to be replaced when doing the swap?

 

It doesnt need to be since IIRC it is metal - unless it is trashed.

Also check the gasket where the TB meets the manifold. Did you torque the manifold down to the factory specs? It doesnt need much torque - too much and you risk cracking the runners.

 

Sounds like the gasket, mine did the same thing after the manifold spacer.

 

Haven't been able to find a leak so far. Kind of hard to test the area where the manifold meets the runners for a leak. I tightened down those bolts tight but did not crank down on them. I don't think I damaged anything there.

The surging today changed to a loping/rough idle that just stays at 1500rpm and I got a CEL P505, which suggests it's the IACV. If I turn off the car and start it again, it immediately goes back to the surging between 1000-1500rpm and randomly will go back to the rough idling at 1500rpm.

It's kind of weird, the TB and IACV are about 2 years old and it was working completely fine before the J37 manifold swap. I either damaged the IACV during the swap, it coincidentally broke/stuck or it's not the IACV.

I'm tempted to replace the IACV if cleaning it doesn't work given the CEL code but it would suck to pay 150 for a new valve it it doesn't fix the problem. It just seems odd for the valve to go bad at 2 years and at the same time I'm doing the manifold swap.

 

I still think you have a vacuum leak somewhere.

 

I agree. Why do you think so?

 

Do you have the TPS and IACV plugs swapped?

 

Take the iacv off and just for grins clean it, spray a little wd40 or seafoam deep creep (what i would use to clean it) where it moves make sure gasket isnt torn and reinstall.

Also make sure things are plugged in correctly and no vacuum lines are off or torn.

 

Unless you removed the IACV from the TB or dropped it at any point, I doubt it would suddenly act up when swapped the manifold. A lot of people have run into idle issues swapping the manifold in.

 

Any idea where they usually wind up finding where the leak is? I'm going to reseat the manifold and TB and check the hoses, but after that I don't know where else to look.

 

Any gasket that you came in contact with. IM to runners, top plate, tb to adapter, adapter to manifold. I cant really narrow it down without having the car in front of me.

If you have the time, toss the stock manifold back on the car and see how the idle is.

 

I'm ordering a set of the oem gaskets, including the metal intake manifold one. I'm planning on going with the CL gasket and not the 09 J37 TL SH-AWD gasket, as it seems this is what most of you used.

 

I had the same issues when I tried the swap but didn't have the time to be able to sink into it to figure it out. I swapped back to my old manifold and it ran perfectly again, I had a vacuum leak somewhere I'm assuming

 

OP: Did you ever figure out the idle problem?
I just installed the 09 TL manifold and I'm having the same issue.
Thanks.

 

I finally got some time to try to figure out what the problem might be.

I had checked for leaks here and there but had no luck isolating the problem.

I took off the J37 manifold and put on the old manifold and the idle is better but I still have a surging idle, not as bad. If I plug up the hole in the TB where the IACV sucks air in the idle is steady.

I talked to Sean at P2R and found out I need to use their gaskets for the TB adapter and am ordering a set. I'm currently using the paper gaskets. I'm also going to try disabling the IACV and see how that goes. It sounds like I take apart the IACV and then disconnect the stepper motor?

 

Yup let us know how is it gonna work out for you.

 

Here's a reply from Sean. I'm going to get more specifics on what area needs to Honda bonded.

"P149 and P141 would be our 2 gaskets that you need. Which are the 2 links that you sent. SO that is correct. Only problem is your still going to need to put a small touch on Honda bond on one corner of the P141. When your lining it all up, you need to pay close attention to the bore on the spacer, to notice what I am talking about. With our gasket on there, it will be about a 1mm opening you will need to fill still. With oem gasket its about a 2mm opening."

 

Finally fixed it. The vacuum leak is between the adapter and the J32a throttle body. The J32a throttle body gasket only covers 2mm of the adapter and as a result there is a leak. I first tried hondabond, it worked for a bit and then leaked again. I used some Permatex Ultra Black gasketmaker and cut out my own gasket larger than the OEM one and that finally sealed the leak and car's idle is perfect.

Now if I could fix the IMRC...

 

Congrats!

 

I read on the 3g tl forum they have the same issues with this manifold. Either everyone is installing it wrong or it is a compatability issue.

 

I think its a few things:

-The gaskets are different sizes between the two models, and there is the smallest amount of gap that can cause a leak i.e. the throttle body gasket, the lower runner to manifold gasket (the EGR ports are different sizes.

-People (myself included) have a tendency to overtorque the bolts on the manifold, cracking the lower runners. Its hard to track down as a lot of people keep focusing on the IACV.

 

Mine was leaking from the P2R adapter right behinf the tps. I put some ultraflange gasket maker and it fixed the vac leak.

Here's mine installed.

 

The top plate is from a 08' Accord auto cause it is cheaper and I have an Accord not Acura.


p.s. I can't seem to edit my post. Is it cause I don't have a very high post count?

 

sorry off topic but what headers are you running?

 

Obx

p.s. now I have an edit button.

 

So now that both of you fixed the idle issue (congrats btw), what are your impressions of the manifold? Do you feel any gains? Any difference in sound?

 

Yeah what do you think of this beast now that it is all in and working correctly. Congrats btw.