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Old 05-22-2010, 09:41 PM   #1
AB-737
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Question Lacking Power 05 Impreza Sport

Ok, so I've been noticing a slow decrease as far as power goes on this car and now its to the point where its really noticable.

I've checked and checked again and tried to find a similar issue and I couldn't find anything. I'm leaning toward two things.

First off the car has 125k miles on all original parts... To my knowledge from when my fiance bought the car nothing has been replaced other than the timing belt and tensioner which I did at the 105k mark.

Now I have a Tactrix cable so I decided to scan it and see if I could find anything odd... Only thing I can see which is OBVIOUSLY the issue is the front O2 sensor reads 14.5-14.70 even when at WOT. I'll attach a scan I just did, but you can see it when I get on it the O2 will dip into the 13's and 12's for less than a half second and then go right back up to the 14's...

So obviously I have a fuel issue somewhere. Could it be a fuel filter? Fuel pressure? (how do you even check that?) Or could it simply be the front O2 Sensor is failing and the ECM is totally lost.

Please let me know what you think.

Link to Scan
http://www.scandepot.net/viewscan.php?pk=5106
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Old 05-23-2010, 02:32 AM   #2
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air filter? clean maf? plugs? wires?
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Old 05-23-2010, 09:41 AM   #3
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MAF cleaned back when I had a odd idle issue, air filter is clean, Plugs have been changed... I'm assuming when I did it that was the third time because stock plugs were not in it when I did it. Platinum went in, and the wires were checked and tested.

Also if I was having a spark issue I would expect that to show rich on my o2 not stoich all the time.
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Old 05-23-2010, 01:18 PM   #4
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What do the OL delay tables have for values. What is the IAM value? Have you tried flashing a stock map over the current map to be sure nothing has changed?

A failing front 02 could certainly be the offending component.

an air filter/fuel filter problem would not cause these symptoms, and an ignition problem should trigger a misfire and/or rich code like you hypothesized.
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Old 05-23-2010, 09:21 PM   #5
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I haven't touched a single thing on the tune of this car, so it is stock. I've never even pulled the map off of it. I bought the Tactrix to troubleshoot this issue, and open myself up to tune my Legacy.

So I can't see any reason for the ECM to be causing the problem. I'll do another check on it to get the info you wanted.
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Old 05-23-2010, 09:52 PM   #6
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Well, I aparently don't have the tools to read the ECM. I'm not able to read the Impreza with my cable... I'm not sure why though. Do I need the jumper cables like others speak of having to use with the WRX's and such? I didn't even think about that since its just an Outback Sport, I thought maybe that wouldn't apply to me.

Either way here is a learning view shot, The IAM is .4

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Old 05-24-2010, 12:17 AM   #7
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Reset the ECU via LV and check it again after a day or 2 driving.

To read the ECU you should just have to connect the green connectors.
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Old 05-24-2010, 01:30 AM   #8
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There's a chance your car isn't tunable. The JDM, EUDM, and ADM 2005 2.5RS Sports only models were old-school ECUs and cable throttle. Then there's a group of USDM 2005 2.5RS Sports that are DBW but still have strange ECUs. Most are the newer ECUs though. If LV read things ok, you should in theory be supported.


Anyway, looking at your log, you never stayed in it long enough to get it into Open Loop. The 05 RS will stay in Closed Loop (14.7) at WOT until somewhere around 5kRPM.
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Old 05-24-2010, 10:32 AM   #9
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What? I find it really hard to believe they stay at 14.7 a/f until after 5k... this car feels nothing like it has in the past, everything below 5k feels much worse than before. Probably due to the really low IAM though. Also why on earth would they make the CL/OL delay that long? what's the point?

I did not have the green diagnostic connectors together when I attempted to read the ECM, and that's because I didn't need that on my 07 Legacy so I didn't think I needed it to read... But after looking at the RR faq on reading you need to have the ECM in diagnostic mode for non CAN ecm's Oh and it's a DBW setup, so its not one of the odd ball cable driven ones.

I re-set the ECM last night via LV, and then I went quickly searching for the green diagnostic connectors but I couldn't find them so I didn't bother, it was 1am and I was tired. Today I found out they are under near the column, and not on the passenger side as they are on the 07, since I can see them blatantly there.

I'll try the ECM read again tonight. And I'll keep an eye on the LV IAM value. I know this car has had some bad ping issues in the past and I couldn't not find the source of that problem, and I'm only guessing but that probably lead to my low IAM and now very low power due to it protecting the engine.
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Old 05-24-2010, 02:15 PM   #10
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Find it hard to believe if you want, but I promise you that I know a hell of a lot more about how that car is programed than you do.

The CL/OL Transition Delay is VERY long. The point is that it's kept in CL under every part of the EPA emissions and mileage tests.

You will not need the green connectors to be connected to take LV snaps or to log. You will only need to connect them if you are going to read the ROM out of the ECU or write a ROM back to it.

You car "had some bad ping problems" because that's the way it was tuned. The stock tune is stupidly aggressive and the car knocks like an SOB. IAMs in the .5's and .6's are normal for a stock tune on 87 octane fuel. Your .4 IAM with negative FLKC is concerning, though.
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Old 05-24-2010, 03:29 PM   #11
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Quote:
Originally Posted by williaty View Post
Find it hard to believe if you want, but I promise you that I know a hell of a lot more about how that car is programed than you do.
Well ok there... No need to get cocky now. That reply could have been worded a bit different.

Quote:
Originally Posted by williaty View Post
You will not need the green connectors to be connected to take LV snaps or to log. You will only need to connect them if you are going to read the ROM out of the ECU or write a ROM back to it.

You car "had some bad ping problems" because that's the way it was tuned. The stock tune is stupidly aggressive and the car knocks like an SOB. IAMs in the .5's and .6's are normal for a stock tune on 87 octane fuel. Your .4 IAM with negative FLKC is concerning, though.
As far as the green connectors that exactly what I was talking about, someone asked what the OL delay was set for, so I was trying to read the rom to tell them. I was able to do the LV snap and reset just fine and I'm aware of how that works, but I wanted to read the ROM so I could get a bit more familiar with how things are setup on it and to do that I need the green connectors connected.
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Old 05-24-2010, 03:37 PM   #12
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All the delay values for A and B are 1250 in the stock ROM. That will see them expire at about 5kRPM, assuming you matted the throttle at 2kRPM. A much shorter delay value is used if you mat the throttle at or above 4kRPM (or if you pass the 4kRPM mark with the throttle down), but the net result is that it still expires around 5kRPM.
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Old 05-25-2010, 07:16 PM   #13
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I asked what your delays were because I thought it had been "tuned" to some degree, but i was just not reading carefully. Your A/F learning is descent so your ecu should be doing its thing correctly assuming all the sensors are ok. Have you changed fuels (especially octane rating) or even the station where you fill up?
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Old 05-26-2010, 06:39 AM   #14
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have not changed octane rating... The car has always received 87 and never had a problem with it. I'm not sure how long this sluggishness has been going on since it's not the car I drive, all I do know is when my fiance would back out of the garage when she would push in the clutch the car would rev up high, this being shortly after starting. Since I've reset the ECM this has gone away. This is the same symptom that caused me to reset the ecm a few months ago too, and it went away then as well... but I guess was starting to come back.

I'll pull another LV shot tonight to see how it's re-learned everything, and I also need to do a check on exhaust parts since it does sound somewhat leaky up front... I'm almost leaning toward a clogged cat forcing exhaust out a leaky header gasket or something. Once on the lift I'll be able to check all that though. And obviously the clogged cat would definately produce the Ping it had and the lower power and all that.
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Old 05-26-2010, 04:36 PM   #15
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How exactly is it being sluggish? When does it do it? Any hesitation? Does it run great in certain situations and not so great in other situations?
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Old 05-26-2010, 07:02 PM   #16
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now that you have the tactrix thing figured out, log data. engine speed, load, FLKC, a/f correction and manifold pressure might be useful, too. anyone (Ty) have any other useful parameters for diagnosis?

log @ idle when warm for 3 sec or so, and then log a 3rd gear WOT pull from 1500 to above 5000rpm if you feel its not going to hurt anything more than it already is.
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Old 05-27-2010, 08:35 AM   #17
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Car just feels down on power all around, never really good anywhere, at least that's what I was told and how it felt the one time I did test it. Her first sign of noticing this was the fact that she felt in some ares she had to actually downshift while going up a hill that she normally wouldn't have had to downshift for.

I will be pulling another LV shot either on Friday or this weekend I've been busy over the past few days and I have a roundy round race to attend tonight so once again busy. But yeah I'll do some more data logging too and possibly pull the exhaust manifolds off if I have time to inspect gaskets, and the cats since it really does sound somewhat odd up front.
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Old 05-27-2010, 04:54 PM   #18
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clogged cat?
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Old 05-28-2010, 12:01 PM   #19
AB-737
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Quote:
Originally Posted by kewlboxer2 View Post
clogged cat?
Yes, clogged CAT

similar to what happened to one of my Beretta's symptoms were very similar... Lacking power and pinging badly, but would datalog just fine, and never threw a code.

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Old 05-29-2010, 10:22 AM   #20
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I'll be taking the car to my fathers inlaw's garage today and getting it up on the lift to remove the exhaust and inspect the cats... Hopefully I find one clogged.

I did the logging as noted and I saw the large delay for OL enable, but it took so long to get to 5k from where I was it happened before that, and it didn't help the situation. The car would be counting knock at idle, so I know something is up somewhere.

Will post pics with what I find.
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Old 05-29-2010, 10:44 AM   #21
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knock sum increase at idle isnt uncommon on a healthy engine, but it should be random and inconsistant increases not a constant, rapid increase.
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Old 05-29-2010, 10:45 AM   #22
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Quote:
Originally Posted by AB-737 View Post
I'll be taking the car to my fathers inlaw's garage today and getting it up on the lift to remove the exhaust and inspect the cats... Hopefully I find one clogged.

I did the logging as noted and I saw the large delay for OL enable, but it took so long to get to 5k from where I was it happened before that, and it didn't help the situation. The car would be counting knock at idle, so I know something is up somewhere.

Will post pics with what I find.
you will need an inspection mirror and good light unless you plan on cutting the catpipe.
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Old 05-30-2010, 09:59 PM   #23
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As noted due to the way the cat is configured you cant really see straight in at the cat, or even out the backside, so on a hunch I was instructed to punch the cat out, so after clearing out both cats my fiance now thanks me and says the car feels worlds better.

Knock no longer counts at idle, yes you still get some low load knock when letting off on the clutch and just bogging around, but at idle it doesnt count up anymore, and there is none at WOT where before there was a lot. I'm in the process of just letting it learn now to see what everything comes up as, but so far its looking good.

I may replace the cat, but I'm in no rush since they want $330 local for it.

I may also be replacing the front O2 just for safe measure since I really don't know what caused the cat to go bad and that may be part of the culprit.

Either way so far the car is a lot better than it was before.
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Old 05-31-2010, 08:18 PM   #24
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Just have an exhaust shop make one up for you for like $150.
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Old 06-01-2010, 12:07 PM   #25
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Quote:
Originally Posted by williaty View Post
Find it hard to believe if you want, but I promise you that I know a hell of a lot more about how that car is programed than you do.

The CL/OL Transition Delay is VERY long. The point is that it's kept in CL under every part of the EPA emissions and mileage tests.

You will not need the green connectors to be connected to take LV snaps or to log. You will only need to connect them if you are going to read the ROM out of the ECU or write a ROM back to it.

You car "had some bad ping problems" because that's the way it was tuned. The stock tune is stupidly aggressive and the car knocks like an SOB. IAMs in the .5's and .6's are normal for a stock tune on 87 octane fuel. Your .4 IAM with negative FLKC is concerning, though.
To follow up on this one a bit more... now that I've been in the file and actually been able to check some things... You are partially correct here, BUT timer or not the table that's keeping the a/f at 14.7 is the OL Primary Fueling table. Up till 4k its requesting nothing over 14.7.

I will be doing some slight tuning on this car as well as replacing the front O2 sensor to see if even more performance will come back.

Stock


VS a tuned one I found on Rom Raider


Quote:
Originally Posted by kewlboxer2 View Post
Just have an exhaust shop make one up for you for like $150.
If I go this route, I'll buy the parts myself and make my own setup. I have a welder and I've done a few systems. I was just looking for something that would be a direct bolt on, and I found one for 199 which isn't that bad.
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