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Old 11-17-2004, 10:36 AM   #1
saint_foo
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Default Rough idling after exhaust upgrades...need help

I have a 2004 WRX Wagon. I was wondering if anyone may have experienced the same thing. Here's the recent exhaust mods:

STi performance muffler
Stromung 3rd cat delete
Gruppe S v2 headers (wrapped and sprayed with silicone paint)
04+ CEL fix for DP (even though I'm running stock DP)
CEL fix for 3rd cat delete (2.2 k om 1/2 watt resistor)

After the negative battery cable was placed back on (also stepped on brake for 15 secs), we idled the car. Ran okay...a bit louder. Shortly afterwards I threw a CEL (haven't had a chance to pull the code yet, but hope to tonight....if so, I'll edit this first post with the code).

Now at idle, it flutters up and down through the RPMs from ~500-1700 or so. I did the muffler and 3rd cat eliminator 2 weeks ago. There was a slight flutter at idle, but now it's really rough. It sounds like a drag car at the staging lights.

One note: I wrapped the headers and sprayed them just prior to reinstall. I'm wondering if there may have been some overspray that might have affected the O2 sensor in the header? Or even the other 02 sensor further downstream. If so, is it possible to clean the 02 sensors with some sort of solvent?

I'll double-check for leaks, but was pretty confident there weren't any. I will probably pick up an Accessport soon just to help w/ the fuel delivery. If I left any info out and need to add it to this thread, I'll edit the first post and color the edit. Thanks for the great support folks!
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Old 11-17-2004, 10:45 AM   #2
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It might be your IAC is dirty which happened to me not long ago

To quote myself earlier:

It's a little module on top of your throttle body with an electrical connection. Remove the two phillips/standard screws and remove it. HINT= Use a WIDE standard screwdriver to remove or you will strip the phillips portion of the screws. Clean with alcohol and Q-tips; it should take you 20 or so to do the job. Reinstall. Turn the car to the ON position, wait 10 seconds, then OFF. Repeat three times, then start your car. This is the advice I got when my idle messed up this weekend. It didn't work, but when I started the car saturday morning after sitting overnight, the idle was fine. My idle problems were too high of an idle and a wandering idle with the associated P1519 code. This is what I did and what fixed it and since it's a cake fix, you might try it as well. There was a surprising amount of gook inside the IAC. Makes me glad that I switched back to the stock paper air filter over my old Perrin foam unit. Cleaner > supposed performance gain.

Dollars to donuts that's your problem too. None of the stuff you did would mess with your idle.
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Old 11-17-2004, 11:08 AM   #3
JDM5LugHatch
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Quote:
Originally Posted by saint_foo
I have a 2004 WRX Wagon. I was wondering if anyone may have experienced the same thing. Here's the recent exhaust mods:

STi performance muffler
Stromung 3rd cat delete
Gruppe S v2 headers (wrapped and sprayed with silicone paint)
04+ CEL fix for DP (even though I'm running stock DP)
CEL fix for 3rd cat delete (2.2 k om 1/2 watt resistor)

After the negative battery cable was placed back on (also stepped on brake for 15 secs), we idled the car. Ran okay...a bit louder. Shortly afterwards I threw a CEL (haven't had a chance to pull the code yet, but hope to tonight....if so, I'll edit this first post with the code).

Now at idle, it flutters up and down through the RPMs from ~500-1700 or so. I did the muffler and 3rd cat eliminator 2 weeks ago. There was a slight flutter at idle, but now it's really rough. It sounds like a drag car at the staging lights.

One note: I wrapped the headers and sprayed them just prior to reinstall. I'm wondering if there may have been some overspray that might have affected the O2 sensor in the header? Or even the other 02 sensor further downstream. If so, is it possible to clean the 02 sensors with some sort of solvent?

I'll double-check for leaks, but was pretty confident there weren't any. I will probably pick up an Accessport soon just to help w/ the fuel delivery. If I left any info out and need to add it to this thread, I'll edit the first post and color the edit. Thanks for the great support folks!


Check all your ground wires. I had something similar to this when I did my Stage 4+ however it was because I forgot to tighten the ground back down. Might not be that at all but its worth a check over your ground wires.

Also when you disconnect the battery from the Negative I thought you were supposed to disconnect for ~ 30-45 mins. then reconnect start the car and let it idle for 10 mins. not touching anything including the brake. Then turn the car off remove the key reinsert it and start the car. Then drive to warm the car up and drive like normal. the ECU will now be relearning. At least this is the way I use to do it and had no problems.

I also threw a CEL before and turned out to be a bad MIL replaced it and trouble free. Check your connections. Did you solder the MIL in place? Maybe a bad solder joint or possible got wet and shorted out.

Also just replace the resister and then take up the connector so it doesn't get wet.

IACV is also a possibility however your car is so new. So I wouldn't believe it to be that. Air in your coolant though. New radiator installed yet?
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Old 11-17-2004, 12:06 PM   #4
saint_foo
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Thanks guys!

Chris, I'll check the MIL...got it from Jard. My mechanic spliced into the O2 wire (the 04 MIL is 1 wire, not the 4-wire deal). He used butt connectors, then wrapped w/ electrical tape. I don't think it got wet b/c we did it Monday and didn't see any rain or puddles. I'll get it on the lift this weekend, but until then I'll doublecheck the stuff again like grounds, etc.

Yeah, I have an upgraded radiator, bled it, it's been run a couple of time, so the liquid's sucked back up. Another note: I installed the Crucial thermostat on Monday too....160 degrees. Had to refill radiator...but the level seems okay...temps are good.

Last edited by saint_foo; 11-17-2004 at 02:22 PM.
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Old 11-17-2004, 02:24 PM   #5
TurbojonLS
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Quote:
Originally Posted by saint_foo
04+ CEL fix for DP (even though I'm running stock DP)
CEL fix for 3rd cat delete (2.2 k om 1/2 watt resistor)

This is really confusing me. Is the resistor fix on the EGT sensor or the last O2 sensor?
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Old 11-17-2004, 02:33 PM   #6
ITWRX4ME
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Is your defroster or A/C on? I know it sounds stupid but it affects the idle.
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Old 11-17-2004, 02:42 PM   #7
saint_foo
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TurbojonLS - ummm, the one CEL fix is the MIL which was spliced in at the last O2 sensor on the midpipe. The other is the jumped CEL fix for the 3rd cat delete...that's in the harness near passenger front strut and airbox....it's the 3rd wire harness, closest to the ground.

ITWRX4ME - I did turn it on later...and off...but it's still all over the place. I mean when I come to a stop, it'll drop to 500 rpms or so....then 15 secs later might hover up and down b/w 1000-1300 rpms. It's quite irregular.

I think I know what you mean when the heater or A/C is on and it keeps kicking in...you hear the engine revs slow down, then it kicks off, the rpms go up. It's a LOT more noticeable than that. I'll keep it on vent, A/C off...and check too.
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Old 11-17-2004, 03:10 PM   #8
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OK, I understand now. Generally "3rd cat" means the last cat in the system, not the uppipe cat. I thought you'd installed both fixes on the same sensor.

When you did your installs, what all did you remove? Were you ever pulling on any vacuum lines? Vacuum leaks can lead to idle problems, but typically its not surging its really high idle.
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Old 11-17-2004, 03:22 PM   #9
saint_foo
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Hey Jon,

Um, basically I'm running the STi uppipe (no cat) and the 3rd cat eliminate on the midpipe. No, didn't run both fixes on the same thing....I believe the MIL fix is if you replace the DP, which I didn't....but I'm running pretty free-flowing.

I don't think we tugged or hit any vacuum lines...but I'll check. The removals on Monday were:

Uppipe
Headers (took off to wrap and paint w/ silicone paint)
radiator hose connecting to thermostat housing (replaced w/ Crucial Racing 160 degrees thermostat)

Replaced:

Coolant (burped it)
STi uppipe
Wrapped headers
02 sensor in headers (put back in)

Spliced into:

rear 02 sensor....added MIL for 04+. that was connected w/ butt connectors and wrapped in electrical tape.

Hope that helps clear up what was done....sorry, brain isn't thinking too well.
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Old 11-17-2004, 03:36 PM   #10
JDM5LugHatch
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Quote:
Originally Posted by saint_foo
Hey Jon,

Um, basically I'm running the STi uppipe (no cat) and the 3rd cat eliminate on the midpipe. No, didn't run both fixes on the same thing....I believe the MIL fix is if you replace the DP, which I didn't....but I'm running pretty free-flowing.

I don't think we tugged or hit any vacuum lines...but I'll check. The removals on Monday were:

Uppipe
Headers (took off to wrap and paint w/ silicone paint)
radiator hose connecting to thermostat housing (replaced w/ Crucial Racing 160 degrees thermostat)

Replaced:

Coolant (burped it)
STi uppipe
Wrapped headers
02 sensor in headers (put back in)

Spliced into:

rear 02 sensor....added MIL for 04+. that was connected w/ butt connectors and wrapped in electrical tape.

Hope that helps clear up what was done....sorry, brain isn't thinking too well.

I don't think you burped it enough! You have air in your cooling system. This is the problem I am pretty damn sure of it. It takes forever to burp it completely and fill that damn PITA cooling system. May also be that thermostat but I would almost be willing to bet you wings thats your problem.
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Old 11-17-2004, 04:54 PM   #11
saint_foo
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Hey all....I think I found it!!! It looks like one of the wire connectors to the IAC got loosened some how. In any event, I drove home from work and it was idling nicely. We'll see tonight and tomorrow morning.

Chris, Ron, Jon, ITWRX4ME thanks a bunch! Mid-A to the rescue!
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Old 11-17-2004, 04:59 PM   #12
el~sharko
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2008 EVO X MR

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I was having this exact same problem. I troubleshot just about everything I can think of. Granted, I have quite a few more mods than you, I was able to get it somewhat under control.
This is what I tried:
replace front 02 sensor (no effect)
Swap IAC from another wrx (no effect)
Replaced IAC gasket
Replaced tb gasket
Check all vaccum lines atleast 50 times
Adjust recirc valve
Replaced fuel pump gasket
Replaced fuel filter
replaced spark plugs
Replaced 2 coil packs
replaced all pre-turbo exhaust gaskets

After all of that, I now have my idle timing fluctuating within 4degrees, and afr is fairly stable. Although my car still almost stalls when coming to stop (less often now) and my vaccum at idle only flucuates from .055-.065 mpa. Seeing that your having similar problems as me, makes me think its something unrelated to my fuel system.
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Old 11-17-2004, 07:27 PM   #13
Unabomber
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Woohoo! Looks like our little "Mid-A in the 2.0 forum" helped. Wings are on you on the 24th as teh Unabomber will be invading your Wednesday Wing night. Which reminds me....I need a place to stay as well.

Ron
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Old 11-18-2004, 07:38 AM   #14
el~sharko
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Quote:
Originally Posted by saint_foo
Hey all....I think I found it!!! It looks like one of the wire connectors to the IAC got loosened some how. In any event, I drove home from work and it was idling nicely. We'll see tonight and tomorrow morning.

Chris, Ron, Jon, ITWRX4ME thanks a bunch! Mid-A to the rescue!
Do you mean the main harness/connector to the solenoid itself?
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