EGR location

Tiny
IRASCIBLE51
  • MEMBER
  • 2004 SUBARU IMPREZA
  • 2.5L
  • 4 CYL
  • 4WD
  • AUTOMATIC
  • 130,000 MILES
I can't find the EGR. I think that this is the problem with this car's inability to idle and run without stalling. I've replaced all of the usual sensors, etc. But this EGR demonstrates the symptoms but I can find the thing to clean and/or replace it. Should be on the drivers side. I've got the gasket that should go in it. I've seen this EGR in the catalogs so I know that it exists and I think that's the one that I've seen the device online. But no pics of where it is (at least not on the normally aspired/2004 2.5 liter engine.
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Thursday, September 26th, 2019 AT 3:46 PM

24 Replies

Tiny
HEYMAN1104
  • EXPERT
Hello and welcome to 2CarPros. I'm trying to look up your 2004 Impreza, but Alldata is giving me screwy information on 2004. 2005 pulls up fine and gives me proper diagrams. So I'm posting them hoping that it's the same.

In the images below, look for #2. That's your EGR.

I would like to know if you've scanned it yet. Being a 2004, any OBD2 scanner can read codes from it. More expensive scanners can give you a live data mode which can be nice. Take that thing off. Clear it out manually as much as possible. Then soak it in carburetor cleaner. Once it dries a bit, close it up, put it back together, and give it a try.
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Thursday, September 26th, 2019 AT 9:17 PM
Tiny
JIS001
  • EXPERT
Hello and welcome to 2CarPros. Wanted to jump in and point out there is a service bulletin for your condition where a head replacement may address your issue. Here is the bulletin

Collision

11

2004 Subaru Impreza

F4-2.5L SOHC

Engine Controls - Rough Idle/Misfire Diagnostic Tips

Vehicle Powertrain Management Technical Service Bulletins Engine Controls - Rough Idle/Misfire Diagnostic Tips

ENGINE CONTROLS - ROUGH IDLE/MISFIRE DIAGNOSTIC TIPS

basics, basics, basics

The Techline receives calls on rough idles and misfire codes on a daily basis. Before you call us, we suggest/ask the following:

Check the ECM reprogramming sheets available on the Subarunet. Com website to see if the particular model you are working on is eligible for a reflash for rough idle/misfire.

If your particular vehicle is not listed or the ECM calibration identification number (CID) matches the one shown on the sheets, then reflashing is not an option. NOTE: Reflashing will NOT address/fix a car that has an actual mechanical issue causing a rough idle. You will need to investigate the problem further to determine the cause. If the car idles fine and just has the misfire code(s), there is a good chance the reflash will fix it.

Does the engine idle fine, but, have a misfire code? If so, it might be a fuel mixture problem. Check the vehicle history to see if the car has been in before for this problem. In some cases, you'll find it has been. If so, was the misfire on the same or another cylinder? If the code was on another cylinder, it might be a fuel related problem. Hopefully you DIDN'T clear the code(s) so you can use the Subaru Select Monitor to pull up the Freeze Frame Data. You'll want to look at the Short Term Fuel Trim (STFT) and the Long Term Fuel Trim (LTFT) readings in the data list. These will give you an idea of what the Air/Fuel Ratio Sensor (A/F) is doing in determining the fuel trim delivered to the cylinders. If the A/F sensor is functioning properly, the numbers you should be seeing for the STFT & LTFT should be somewhere between a +5% to a -5%. Slightly higher readings are ok but if you have a reading in the double digits, typically T2% or higher, it usually indicates there is a problem with the A/F sensor. Trouble shooting of the A/F sensor should be performed to determine if it is functioning properly or another condition (vacuum leak etc.) Is influencing the A/F sensor readings. Our A/F sensor readings will max out at 37.5 %. If the number is a positive (+) the car is running lean. This is usually when we see the misfire and rough running concerns. There is simply not enough fuel getting into the cylinder to support combustion. This is referred to as a lean miss. A negative (-) number is of course a rich mixture and is not usually a cause for a misfire.

If the car has an actual rough idle, there are many things that you can do to track down the cause. Check the plug wire(s), coil(s), plug(s), and injector(s). If the code is always on a particular cylinder, try swapping that injector with a known good cylinder and see if the code follows the injector. Then swap a plug, then coil. This is what we'll suggest if you call us. If the code moves with the injector, then you have a bad injector. If it doesn't follow the injector, there is most likely something wrong internally with that particular cylinder however, the pins in the injector connector will need to be checked to see if they might be the problem. If everything external has been inspected and ruled out as the cause, the problem must be something internal to the engine. It could be a carbon buildup on the valves or varnish in the valve guides. It could also be a valve adjustment that is too tight. Further tests are necessary.

Hook up a vacuum gauge to a source of engine vacuum (below the throttle plate). A good running engine will have between 16" to 22" of intake manifold vacuum depending on the altitude. The needle should be steady on the gauge and not bounce around. A slight quiver to the needle is acceptable. If the needle is bouncing around 1" or more, it shows you there is a cylinder sealing problem (valves or rings). Most often it is the valves causing the problem. However, this test doesn't pinpoint the exact cylinder(s) at fault. If there is a misfire code, you can be reasonably sure that the code indicates the problem cylinder(s). If there is no misfire code, you'll need to perform a compression and cylinder leakdown test. We always recommend that a compression test be followed up by a leakdown test as we've seen many cases where an engine might pass a compression test but, fail the leakdown test. Most importantly an accurate leakdown test will help identify where you should look for the leak:
intake valve, exhaust valve, or rings. When you perform a leakdown test, always follow the procedure recommended by the equipment manufacturer to assure that the test results are accurate. Refer to the 04/95 Tech TIPS (available on the STIS website) for additional information concerning compression and leakdown testing.

If your testing has determined that the valves are the problem and you've checked the adjustment, the head(s) will need to be removed for further inspection. If the cause is then determined to be a carbon buildup, usually just cleaning the valves and the guides is all that is necessary to repair the problem. If the valves are reinstalled into their original positions (and they should be), everything should be fine, but you can lap the valves in by hand if you wish to insure a tight seal. We do not recommend cutting or grinding the valves or their seats at any time.

In closing, there are other things that can cause rough idles and misfire codes. These are just the most common ones we deal with here on the Techline and the methods we suggest you use.
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Thursday, September 26th, 2019 AT 11:47 PM
Tiny
IRASCIBLE51
  • MEMBER
Hello, I thank you all here.

I do have a OBD Scanner and the only thing that it came up with at this time was something about Barometric Pressure. Yeah, that I think indicates low vacuum. I think this is about a vacuum issue. The local experts at the Subaru dealer (well not actually a licensed Subaru type of shop). They are the ones pointed me to the EGR (but I can't find the doggone thing. And this should be a obvious "given"). Yeah, I subscribed to the AllData service too about this thing but found no helpful diagrams there either.

I've got to finish reading your replies here and I'll get back to you ("you's")
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Friday, September 27th, 2019 AT 9:36 AM
Tiny
IRASCIBLE51
  • MEMBER
Yes, according to the diagrams here, this thing (at least what looks like) should be very obvious (maybe I'll take the air filter housing off and look). Regarding the possibility of head gaskets discreps. Yeah, I know and I've also got a Forester with head gaskets problems but I've had this one already done and not long ago and she was running nice nice and no oil leaks (Six Star multi-layer gasket).
I'm going to have to go back over here your insights on the readings coming out of the OBD Scanner.
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Friday, September 27th, 2019 AT 10:13 AM
Tiny
IRASCIBLE51
  • MEMBER
Whoa ho folks! There is some really good stuff here (and how do I reimburse you all should this prove successful?)
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Friday, September 27th, 2019 AT 10:17 AM
Tiny
IRASCIBLE51
  • MEMBER
I can read STFT & LTFT again and with your descriptions here? Also, I will check my vacuum readings again and try and decipher from your advice.
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Friday, September 27th, 2019 AT 10:21 AM
Tiny
KEN
  • ADMIN
Hello,

This sounds like the throttle bore needs to be serviced. here is a guide to help you fix the problem:

https://www.2carpros.com/articles/throttle-actuator-service

Please run down this guide and report back.
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Sunday, September 29th, 2019 AT 12:55 PM
Tiny
IRASCIBLE51
  • MEMBER
Sorry for the delays here, the internet (lousy Frontier Communications) has been down since last Friday.

Bob
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Thursday, October 3rd, 2019 AT 11:02 AM
Tiny
KEN
  • ADMIN
No problem please let me know after the service.
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Thursday, October 3rd, 2019 AT 11:02 AM
Tiny
IRASCIBLE51
  • MEMBER
Hi Ken,

Hoping that this horrible Frontier DSL stays up long enough to respond here. I did clean the throttle body some time ago. I am still looking for the EGR (a good photo) I had my wife take some pictures of my Impreza engine to send back to you folks if only this internet would stay up long enough to get them to you. I still haven't find the EGR even though I looks like and where I should be looking for it. Thank you all here. Appreciate it.
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Thursday, October 3rd, 2019 AT 11:15 AM
Tiny
IRASCIBLE51
  • MEMBER
ATTN: JIS001

Where is this "Throttle Plate" that you spoke of for the vacuum readings test? I'm still looking for a good photo of the EGR and it's location too. I'll get some pictures of my engine compartment to you folks hopefully soon.

Robert P.

Yes, I am still dealing with a on and off DSL Internet here (and the service bureau is apparently located in the Philippines. Adding to the confusion with getting my troubles router fixed).
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Thursday, October 3rd, 2019 AT 11:25 AM
Tiny
KEN
  • ADMIN
Here is what I found for you. Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.
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Thursday, October 3rd, 2019 AT 12:37 PM
Tiny
IRASCIBLE51
  • MEMBER
Trying to send zip file with pictures that my wife took from her smart phone. Getting Filetype not allowed. Please help/advise.
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Friday, October 4th, 2019 AT 6:12 AM
Tiny
KEN
  • ADMIN
No Zip file, upload them individually.
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Friday, October 4th, 2019 AT 12:28 PM
Tiny
IRASCIBLE51
  • MEMBER
I think that I've gotten this (at least for now or until next time). Hope so and hope they are some value as far as what you can see here. I haven't been able to find anything looking familiar.

Thanks,

Bob
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Saturday, October 5th, 2019 AT 6:32 AM
Tiny
KASEKENNY1
  • EXPERT
Hi,

Just to jump in, it looks like it should be to the driverside of the coil. I circled what appears to be the EGR. Its a little far away so I can't confirm but you should be able to follow a line from the exhaust up to the engine. The valve will be attached to that line before it goes into the engine.
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Tuesday, October 8th, 2019 AT 3:09 PM
Tiny
IRASCIBLE51
  • MEMBER
Dear Kase Ken and all here,

I believe this is the idle air control valve. From what I have seen this EGR should be behind # 4 cylinder (behind the engine to the firewall). But I haven't seen anything that looks like what's in the pictures of the EGR from the catalog. AllData can show me no pictures either. I've seen what it looks like on a bench at a shop but can't find that in the car (unless the intake manifold has to be lifted). I've looked for pipes from the top of the engine to the bottom or side of the engine (but I've seen other than two pipes which I think are probably cooling/heater coolant water pipes). This should be very obvious but isn't unless I'm looking is a totally wrong place. Please help. Appreciate it.

Bob
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Wednesday, October 9th, 2019 AT 6:40 AM
Tiny
IRASCIBLE51
  • MEMBER
This diagram that you have here is from a 2004? I have seen a device that looks similar with a very and obvious round top so I'd safely say."Not on this vehicle" here.
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Wednesday, October 9th, 2019 AT 6:46 AM
Tiny
IRASCIBLE51
  • MEMBER
Sorry, failed with that download picture of air fuel valve (from AutoZone catalog).
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Wednesday, October 9th, 2019 AT 6:58 AM
Tiny
IRASCIBLE51
  • MEMBER
(air fuel idle mix valve).
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Wednesday, October 9th, 2019 AT 6:59 AM

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