New(used) STi, Major Maintenance Questions, Weird CEL and well, even datalog fun!

The new 05 STi I got came with a APS CAI, COBB downpipe and Greddy EVO2 exhaust. It has a COBB radiator shroud and it has about 99500 miles. I'm planning on doing a full service soon by changing the fuel filter, spark plugs, tranny oil, rear diff oil, oil, oil filter and maybe even bleed the breaks. I'll probably also replace the timing belt.
For the fuel filter I'm going OEM.
Tranny oil is Motul Gear 300 75W90
Rear diff is Motul PA90
Spark Plugs I went with NGK One Step Cold Part 2309
Oil will be Rotella T6 synthetic and oil filter is OEM.(done)-- turned out the dealer had a "Mighty Guard" Oil filter and the oil was so...watery. I changed it pretty quick.
I havent decided if I should bleed the breaks or the timing belt.
I also recently received a complete set of injectors that fit my car(wrong part shipped)! I'm debating whether or not I should just replace them all.

What do you guys think about all this. Anything I'm missing or anything else you guys would recommend I check out? I'm actually researching replacing the fuel pump since I'm also replacing the fuel filter. I haven't found a concrete "yes or no" answer to whether it is proper that I get a Walbro at just Stage II.

Another issue I've had was that since going Stage II, I was getting a P0301- or misfire on 1. I reset the comp a couple of times and the code hasnt comeback There is also a PFFE error of which I have no idea what it means. She idles pretty rough, starts off at about 1000 RPM but then dwindles to the middle mark between 0 and 1000 which I believe is 500 RPM? and kinda settles there. She seems to be struggling on idle, not very steady, some shaking and the engine sounds like it is struggling a bit. Once I'm driving there isn't any noticeable loss of power. I haven't gotten the misfire CEl today, but now she is throwing a Evaporative Emissions Leak loose gas cap. I didnt write down the exact code. I tightened the gas cap a couple of times, reset the comp and it goes aways for a while but randomly shows up at highways speeds. Recently my exhaust hangers ripped off and I drove around without noticing until my GF pointed out that my exhaust was hanging and bouncing around. I wonder if that might have caused anything...

Anyways, I've looked at some threads about misfires but I don't feel like if I know the proper procedure on how to diagnose it since there isn't any clear steps posted anywhere. If there is I would appreciate it if you guided me in the right direction. Any ideas of what could be happening?
I'm hoping that once I do the overhaul of maintenance she shapes up, but I would like to find any other problems I have to consider so I can do it all in one weekend. I got 2 year insurance from the dealer I got her from but I would rather try to figure out if it is simple on my own as I have a high deductible anyways. If it is something more serious then...i hope its bad enough so they just give me a new engine!

Someone recommended that I check my fuel trims. He said that I might be looking at a vacuum leak somewhere. I did some data logging and well, I have no idea what I'm looking at:

One log:

https://docs.google.com/spreadsheet...hLdG1teXZQeVNxYWtOZTJEVE14aHhXZ3c&output=html
Most Recent Log:

https://docs.google.com/spreadsheet/pub?hl=en_US&hl=en_US&key=0AtK3KbA0DUhLdEY1VTVfVHAxekw0UTJmbEJ0QUc1Unc&output=html


I would appreciate any input from you guys on what all these numbers mean. I tried researching on how to do a datalog properly but no avail so I just took the car out for a spin. Any input would be appreciated it. The Recent Log was over a period where I drove on the streets and at the end got onto the highway at around 65-75mph. I got the parts I need to do my own vacuum leak tester tool. I must admit that I have no idea where I should check for leaks though. Pictures would be nice, I would also like to try that spraying starter fluid and checking for surges in case of a leak. I love DIY stuff. Just love it. Thank you guys in advance for the help and if there is anything you guys need to know more about please let me know. I want to have her in tip top shape. I probably should mention that the previous owner seemed to know what he was doing...except for the tires. It has "Sunew" tires on the front and " michelins" at the back. What do you guys think about THAT setup? LOL

Couple of questions. Is the car stage 2 with a cobb AccessPort or a pro-tune? Does it have upgraded injectors as far as you know? Did you already do the fluids and spark plug change?

If the car is running just a stage 2 AP map, take off that intake asap and put a stock one, or cobb short ram on. Our cars do not like cai's without being properly tuned foe them. I so not know whether this directly contributes to your misfire or not, but it could. It could also have an impact on your idle.

I had misfire codes not too long ago and it ended up being bad injectors... you said you have new ones so it might be worth throwing those in just to see. As for the fuel pump, are you going to do some big upgrades (turbo, E85)? A walbro isn't really necessary from what I've heard unless you are, or your stock pump quits on you.

Check for vacuum leaks, clean the maf sensor with proper cleaner, fix your exhaust hanger, check your spark plugs and coil packs.

Hope some or this helps!

jswansti said:

Couple of questions. Is the car stage 2 with a cobb AccessPort or a pro-tune? Does it have upgraded injectors as far as you know? Did you already do the fluids and spark plug change?

If the car is running just a stage 2 AP map, take off that intake asap and put a stock one, or cobb short ram on. Our cars do not like cai's without being properly tuned foe them. I so not know whether this directly contributes to your misfire or not, but it could. It could also have an impact on your idle.

I had misfire codes not too long ago and it ended up being bad injectors... you said you have new ones so it might be worth throwing those in just to see. As for the fuel pump, are you going to do some big upgrades (turbo, E85)? A walbro isn't really necessary from what I've heard unless you are, or your stock pump quits on you.

Check for vacuum leaks, clean the maf sensor with proper cleaner, fix your exhaust hanger, check your spark plugs and coil packs.

Hope some or this helps!

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It is just the Stage II AP map. I would slap on the stock intake but since I got the car already modded I don't have one at hand. However, the APS is supposed to be good enough for Stage II and I used to run it on my old car with no problems. However, I'm going to do a Protune as soon as I get all the maintenance out the way.

The misfire code is long gone at this point. Now I'm just getting the "emissions leak(loose/off fuel cap)" CEL which is why I was advised to check my fuel trims using the AP. I have no idea what those numbers mean but I'm currently doing some research on the topic. I don't know what happened to that misfire code but it hasn't comeback since that day. The only thing I have done so far is the oil and oil filter change. I also fixed all my hangers with COBB ones(much better than the temporary ones I got at Autozone) All the other fluids, parts and whatnot are on the way. I'm hoping to knock it out this weekend and go from there. I'm still debating whether I should replace the timing/camshaft belt. For it's mileage it is recommended but that seems like a tall task.

I asked about the Walbro b/c on other forums a lot of people seem to be changing it. And since I'm replacing the fuel filter, I figured I might as well do a fuel pump change since it is so much work to take off the back seats and everything. I don't plan on getting a bigger turbo, probably just getting the most out of the stock one for a while. A Protune is in order I know. I think within the next month or two. Would that change how you feel about the fuel pump?

Anyways, I'm going to do a pressure leak test today after work. I'm just not sure where I should check for leaks. I cleaned the MAF already. Thank you for your input!

As far as the fuel pump goes, i guess its just up to whether you wanna spend the money on one or not. It absolutely doesnt hurt to get one, especially if you're going to get a protune soon. And if you decide to jump up to E85 or a bigger turbo you wouldn't have to worry about it. I was just trying to say that if you're doing a basic stage 2 protune, you probably wouldn't have to worry about it.

My evap system knowledge is close to none so ill let others give advice. Hope you get it sorted out!

jswansti said:

As far as the fuel pump goes, i guess its just up to whether you wanna spend the money on one or not. It absolutely doesnt hurt to get one, especially if you're going to get a protune soon. And if you decide to jump up to E85 or a bigger turbo you wouldn't have to worry about it. I was just trying to say that if you're doing a basic stage 2 protune, you probably wouldn't have to worry about it.

My evap system knowledge is close to none so ill let others give advice. Hope you get it sorted out!

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Yeah that was my gut feeling about the fuel pump. Thank you for your input!

Fujiwara said:

Has the fuel filter ever been changed? Might as well toss $90 or so at it if you haven't changed the fuel filter.

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I don't know if the fuel filter has been changed or not. I do plan on replacing it and the part is on the way. That is why I asked about upgrading to a Walbro fuel pump since I'm going to take the car apart to replace the filter I figured I might as well upgrade the fuel pump. Especially now that I plan to get it Protuned.

And...what the heck is the evap part you said could be throwing the error?

Update: Ok, I found some stuff about the Evap System. Why would you take this out?

I agree with everyone on the fuel pump. It couldn't hurt. But if you wanted to know for sure if you absolutely needed one or not just look at your Injector Duty Cycle at WOT. If they are approaching 95% then you could stand to use a new one.

However before you do that there are some things about your logs that concern me. Although your A/F learned is okay, your A/F correction is consistently 20 or more and this indicates that the ECU is compensating for something by adding 20% more fuel to achieve the commanded AFR. That is excessive IMO.

It would be helpful if you could take another log for us, only this time log the parameters as suggested in this write up http://www.igotasti.com/vBforum/showthread.php?213-Newbies-Guide-to-Logging. When you do this please warm up the car fully and then reset the ECU. Drive for at least 10 minutes before you start logging. Then log for about 15 minutes while driving normally around town and on the highway. No WOT. When you get home just let the car idle for about 3 minutes before you stop the log.

This will tell us allot... but right now, with out going to deep into it, I'm thinking pre-turbo leak or, as previously suggested, the intake.

It also might not hurt to get yourself a compression and leak-down test done. There is a lot of value in that test alone... Not only will it prove or disprove the health of your motor but it will also give you a reference point to go back to later to judge the deterioration of the motor over time.

Please do this.

Also... How sure are you that those new injectors you have are stock. If you are positive of that it may not hurt to just throw those in. I also think you should be replacing your timing belt soon since you have an excess of 70,000 miles. Also check the gap on the plugs. These engines are very finicky over that and you will get misfires and poor idle as a result if they are not gapped properly.:tup:

Fujiwara said:

People remove stuff while building... I have plenty removed from my setup. It comes down to a couple different factors depending on the part.

A fuel pump is worth the investment.

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Alright, I'm pretty sure I'm going to go ahead and replace the fuel-pump. I'm going to go under the car to check if anything is missing LOL. Thanks a alot for your advice!

HolyCrapItsFast said:

I agree with everyone on the fuel pump. It couldn't hurt. But if you wanted to know for sure if you absolutely needed one or not just look at your Injector Duty Cycle at WOT. If they are approaching 95% then you could stand to use a new one.

However before you do that there are some things about your logs that concern me. Although your A/F learned is okay, your A/F correction is consistently 20 or more and this indicates that the ECU is compensating for something by adding 20% more fuel to achieve the commanded AFR. That is excessive IMO.

It would be helpful if you could take another log for us, only this time log the parameters as suggested in this write up http://www.igotasti.com/vBforum/showthread.php?213-Newbies-Guide-to-Logging. When you do this please warm up the car fully and then reset the ECU. Drive for at least 10 minutes before you start logging. Then log for about 15 minutes while driving normally around town and on the highway. No WOT. When you get home just let the car idle for about 3 minutes before you stop the log.

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Thank you so much! This is what I was waiting for. I'll do a good log tomorrow now that I know the proper way to do this. I figured my A/F Correction was acting whack. I kept reading that somewhere between 8-10% was normal. If it's an intake then the Protune should fix it. If it isn't, then I hope it isn't anything I would need to take her in for.

HolyCrapItsFast said:

This will tell us allot... but right now, with out going to deep into it, I'm thinking pre-turbo leak or, as previously suggested, the intake.

It also might not hurt to get yourself a compression and leak-down test done. There is a lot of value in that test alone... Not only will it prove or disprove the health of your motor but it will also give you a reference point to go back to later to judge the deterioration of the motor over time.

Please do this.

Also... How sure are you that those new injectors you have are stock. If you are positive of that it may not hurt to just throw those in. I also think you should be replacing your timing belt soon since you have an excess of 70,000 miles. Also check the gap on the plugs. These engines are very finicky over that and you will get misfires and poor idle as a result if they are not gapped properly.:tup:

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I'm actually going to do one of those compression tests that you can make on your own. Or are you talking about a test that a professional should do? I don't know what a leak-down test is but I will make sure to look that up.

I'm sure the injectors are the correct ones b/c I called the Subaru dealership in Plano and asked about the part number. The part number is 16600AA170 if you guys wouldn't mind double-checking. I ordered a fuel filter and instead got the full set of injectors. I don't think I can complain about that! I didn't even think about checking the plugs yet since I wasn't considering anything but a vacuum leak. I ordered new plugs(NGK One-Step Colder--after much reading and research done) so when they come in I will change them in.

I think you are right about the timing belt. Well, I know you are right but they are so damn expensive!

EDIT: I just looked up compression test. I get you now. Do you recommend this after I get through with the massive maintenance or before?

Fujiwara said:

Hard part will be choosing a pump. Walboro 255, DW300, aeromotive 340, walboro 340.

You have a couple different choices. I'll be replacing my fuel pump in the near future and I'm having a hard time choosing... I've seen the massive difference the dw300 reduced injector duty cycle in a 2011 wrx, bringing it down by 15%. It makes me wonder how much better a 340LPH pump would work. I've heard all kinds of things about each of the pumps except for the new walboros because they have not yet been used for extended periods of time. The DW300 is E85 certified, but I've also heard the gears are made of brass. Good luck choosing a fuel pump, if you're simply looking for an inexpensive replacement that will lower IDC, the walboro 255 can be found at very reasonable prices.

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30 minutes into research the pumps and I know what you mean. I was leaning towards the 255 since I don't plan on going to a bigger turbo and getting what I can with the stock. What do you think about that? I've been super focused on getting my car maintenance updated so I haven't looked at potential performance based setups at all.

SirMyztiq said:

Thank you so much! This is what I was waiting for. I'll do a good log tomorrow now that I know the proper way to do this. I figured my A/F Correction was acting whack. I kept reading that somewhere between 8-10% was normal. If it's an intake then the Protune should fix it. If it isn't, then I hope it isn't anything I would need to take her in for.



I'm actually going to do one of those compression tests that you can make on your own. Or are you talking about a test that a professional should do? I don't know what a leak-down test is but I will make sure to look that up.

I'm sure the injectors are the correct ones b/c I called the Subaru dealership in Plano and asked about the part number. The part number is 16600AA170 if you guys wouldn't mind double-checking. I ordered a fuel filter and instead got the full set of injectors. I don't think I can complain about that! I didn't even think about checking the plugs yet since I wasn't considering anything but a vacuum leak. I ordered new plugs(NGK One-Step Colder--after much reading and research done) so when they come in I will change them in.

I think you are right about the timing belt. Well, I know you are right but they are so damn expensive!

EDIT: I just looked up compression test. I get you now. Do you recommend this after I get through with the massive maintenance or before?

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I would think before... If it turns out there is something wrong with the motor you can have everything taken care of all at once versus doing something first and then find out you have to take it all out and do it again anyway.

If you do the test yourself you can find the tools at your local auto store for under 50$. When you do the test follow the instruction and do it on a warm motor with the spark plugs removed and the throttle plate open or the brake booster vacuum line removed.

The injectors are good... I would go ahead and change those out for good measure since you have them.

rek888v2 said:

Also, get the Motul crap out that trams, Extra S in an STi tranny is the only way to go!!!

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LOL!

Do you know how long I spent researching this?! There was a consensus that Motul worked great for our vehicles, with others swearing by the Extra S. Since I already ordered the Motul, I think I'll stick with it and see the results. I will make sure to get back to you on how that goes. One thing I've learned is that much of this is personal preference. I wish there wasn't personal taste involved and there was a wide consensus on what is best

rek888v2 said:

Well, as teh igotasti bearer of bad news, Ill start... PFFEE is a generic CEL code and is to be ignored... The P0301 from your car could be a batch of bad gas, bad coil pack, fouled or improperly gapped plug or a cracked ringland. have a compression check done immediately and get back to me with results.

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I will do this ASAP. Thanks for your input!

Is Extra S the Subaru issued fluid? I've heard only to use Subaru fluids for the trans, diffs, etc. Pretty much everything except the motor oil ha.

If you're gonna do a timing belt change along with your massive maintenance work, I recommend looking into getting a Gates timing belt kit. Ill bw getting one and doing pretty much the same thing you are after winter. Gotta do my 90,000 mile service and belt at the same time.

Also, I still think you should set aside the APS until you go in for the tune. I didn't put mine on until a couple hours before my tune. I can usually find a stock, spt, or cobb intake on craigslist or local forum pretty easily and cheap. Someone might even lend you one for beer or something. The intake might not be causing any issues, but you might be surprised at how she runs if you took it off for now.

jswansti said:

Is Extra S the Subaru issued fluid? I've heard only to use Subaru fluids for the trans, diffs, etc. Pretty much everything except the motor oil ha.

If you're gonna do a timing belt change along with your massive maintenance work, I recommend looking into getting a Gates timing belt kit. Ill bw getting one and doing pretty much the same thing you are after winter. Gotta do my 90,000 mile service and belt at the same time.

Also, I still think you should set aside the APS until you go in for the tune. I didn't put mine on until a couple hours before my tune. I can usually find a stock, spt, or cobb intake on craigslist or local forum pretty easily and cheap. Someone might even lend you one for beer or something. The intake might not be causing any issues, but you might be surprised at how she runs if you took it off for now.

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On IWSTI.COM, many swear by the Gear 300 stuff and the PA for the rear. Others don't, so I came to the conclusion that all of our cars react different to the type of fluids so I'm going to try the Motul and see where that takes me.

Timing belt: I was actually going to purchase that kit(comes with a water pump I think) So, it is good to know that those are of good quality.

I'm going to look around for a better intake so I can have it temporarily until I get my tune. I appreciate all of your input. Now, to find a guy to loan me his...lol

Yeah, cars all react differently. I've had all my big maintenance done at or by a Subaru certified shop so I've only ever used their fluids, except motor oil. I have a stock intake system, but I don't think you live near me! Reks pretty much has an Sti graveyard of parts, or used to.

rek888v2 said:

Ive ran Extra S in all 5 of my STi's for that reason. Ive tracked them all in every way possiable. The Extra S was specifically designed for Subie 6 Speeds and is even used on the Rally cars and in PPG build 6 Speeds. It has something to do with the pumping system in the 6 speeds and the composition of Extra S over all. Now, WRX 5 speed guys talk about Motul and some other fluids being great for them due to their over wheling failure rate at higher HP. You can try the Motul but myself and most big name subaru builders will recommend Extra S.

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Interesting. There are so many different viewpoints about this. Some say Motul 300 and Motul 90PA runs great. Others even mention Valvoline and Redline! I guess I'll find out soon.
Oh and rek...you wouldn't have a stock air box for a 2005 STi just taking up space anywhere would you?
I have a question about the timing belts. For the 100K maintenance, I just need the belt right?

Should I get this:
http://www.rallysportdirect.com/Gates-Timing-Belt-Subaru-Turbo-Models-inc-2002-2011-WRX-STI



Or...I'm looking at timing belts and Gates sells this SWEET Timing Belt Kit:

http://www.rallysportdirect.com/Gates-Timing-Belt-Kit-w-Water-Pump-Subaru-Turbo-Models-inc-2005-2007-WRX-2004-2007-STI

Get the kit for sure... it is a good price and you will most definitely want to replace the idlers and tensioners while you are in there... They are a wear item and should be replaced.

^+1 You'll want the kit for sure. I didn't look at the link you posted, but Jordan @ DEFINED performance is a vendor here and has hooked a lot of us up with sweet deals on all sorts of parts.

rek888v2 said:

I do have an airbox Ill dig out and I like the gates stuff but also look at the JDM STi timing belt and the OEM Subaru timing gear as well.

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I thought Reks could help ha ha!!