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

[SirMyztiq]

Update: I pulled the O2 plug. Assuming I pulled the correct one. I pulled a plug with an end connected to the engine. It was covered in a blue covering and it looked like an O2 sensor. Anyways, when I pulled it I got a P0031 code so I think it is the right one.

When I pulled it and started the car, it was idling at higher RPMS, about the 1500 mark. Then it went pretty insane. Dropping almost to 500 RPM and then back up to 1500RPM and everything in between.

 

[HolyCrapItsFast]

Okay.. Plug that back in. Don't reset the ecu... Now unplug the MAF sensor (on the intake) and try it again.

 

[SirMyztiq]

Okay.. Plug that back in. Don't reset the ecu... Now unplug the MAF sensor (on the intake) and try it again.

Here is what I found:

I unplugged the MAF and it idled at around 800 and IT STAYED THERE. Now, I'm a little sensitive to what a good idle is supposed to sound like but I mean it felt pretty steady. There was no up and down rough feeling anymore. Anyways, a picture is worth more than words(in this case sound so here you go)


The RPM stayed at around the mark at the beginning of the video. Towards the end I plugged the MAF back in and it immediately went back to a rough idle. I was using the phone as a flashlight too so pardon the quick movements. I'm guessing we have found our culprit?

On a side note: The intake makes an annoying squeak b/c of the CAI rubbing against the metal. Any hints as to how to deal with this? And where the heck do you get those tiny flange bolts? I'm missing one on the MAF(I think you can tell on the video) and they are a BITCH to find.

http://www.youtube.com/watch?v=b4MfOr5SzwM

 

[SirMyztiq]

Buy some MAF cleaner (its in a spray can and be bought at any autoparts store) and clean the MAF doing like the directions say. If that doesnt help, Ill send you a known good MAF to use. I have 5 of them....

I cleaned that MAF at least three times while I was trying to troubleshoot the issue. I also used some electronics cleaner on the connector a couple of times to clean the connections. I just never figured that it was the issue! I appreciate your generosity!

 

[HolyCrapItsFast]

This actually might still not be the problem. When you unplug the MAF this puts the ECU into a pseudo speed density mode and it uses the throttle position sensor, O2 sensor and the MAP sensor to derive fuel. The only thing this tells us really is that the O2 sensor is working. At this point it could be the MAF sensor or it still could be the Intake or it still could be a leak that you are not finding. If the intake does not fix the problem then hit Gino up for the MAF sensor. We will have to go through the process of elimination here and rule out things one at a time.

You might also want to consider getting a proper boost leak test done. There is a write-up on here that shows you how to make your own tester

http://www.igotasti.com/vBforum/showthread.php?1215-Do-a-Vacuum-Leak-Test

 

[SirMyztiq]

This actually might still not be the problem. When you unplug the MAF this puts the ECU into a pseudo speed density mode and it uses the throttle position sensor, O2 sensor and the MAP sensor to derive fuel. The only thing this tells us really is that the O2 sensor is working. At this point it could be the MAF sensor or it still could be the Intake or it still could be a leak that you are not finding. If the intake does not fix the problem then hit Gino up for the MAF sensor. We will have to go through the process of elimination here and rule out things one at a time.

You might also want to consider getting a proper boost leak test done. There is a write-up on here that shows you how to make your own tester

http://www.igotasti.com/vBforum/showthread.php?1215-Do-a-Vacuum-Leak-Test

Alright! The intake should be coming in sometime today. I will report the results!

I did the boost leak test posted on that link combined with all the other tricks and I couldn't come up with anything. If it isn't the intake or MAF sensor then I will have to do another boost leak test, maybe with a compressor this time!

 

[HolyCrapItsFast]

Keeping my fingers crossed that it is either the intake or the maf.

 

[SirMyztiq]

I wanted to pry y'alls brain on the whole headers/uppipe deal. I'm pretty confused as to how they all tie together. If I wanted to go with the EWG setup, I couldn't get headers? I've noticed headers come with a builtin uppipe for the most part. I'm not exactly sure of the functionality of it all, even after some research!

 

[SirMyztiq]

Ok, lets break this down, Headers and uppipes are almost a package deal due to the flanges that mount from the headers to uppipe. Some companies stay with the stock 2 bolt design and some go to a 3 bolt. Youll have to research this. Now, as far as EWG's go theres 3 options. 1. but the flange and have it welded on the uppipe 2. but a stock lication turbo uppipe with a flange welded on or 3. go rotated turbo and most already have a EXG flange on them.

Ok, awesome. So I understand now why some go the EWG route and just have Port and Polish done(for example by Grimmspeed) and they get the Xpipe as a package deal.

Man, it is so hard to not just go all out and buy all this stuff. But I still need to replace the timing belt and do some other maintanence stuff like flush the coolant and power steering and maybe even the brake lines. But, it is so tempting...

 

[HolyCrapItsFast]

The other thing you want to concern yourself with is the diameter of both the header runners and the up-pipe.

The larger diameter headers and up-pipes are better suited for large turbo applications but only when you have also performed other modifications to improve overall flow through the engine like ported head work, TVG deletes, Ported matched header and up-pipe and cams. The larger diameter pipes will give you the capacity to flow more for larger turbos and allows for more top end power.

The smaller diameter pipes are better suited for stock and smaller turbos such as an 18G or 20G or a GT28R or an FP Green and the smaller diameter pipe allows for greater exhaust gas velocity at lower speeds which allows for faster spool and better flow characteristic for the smaller turbos. The top end will not be as good.

The three bolt headers usually have the larger 2.5" up-pipe. I know the GT spec, ProSport and Tomioka have big up-pipes.

 

[SirMyztiq]

The other thing you want to concern yourself with is the diameter of both the header runners and the up-pipe.

The larger diameter headers and up-pipes are better suited for large turbo applications but only when you have also performed other modifications to improve overall flow through the engine like ported head work, TVG deletes, Ported matched header and up-pipe and cams. The larger diameter pipes will give you the capacity to flow more for larger turbos and allows for more top end power.

The smaller diameter pipes are better suited for stock and smaller turbos such as an 18G or 20G or a GT28R or an FP Green and the smaller diameter pipe allows for greater exhaust gas velocity at lower speeds which allows for faster spool and better flow characteristic for the smaller turbos. The top end will not be as good.

The three bolt headers usually have the larger 2.5" up-pipe. I know the GT spec, ProSport and Tomioka have big up-pipes.

Yeah, I just got done reading many reviews/install/notes on the topic. Good to know, good to know. I talked to Cobb in Plano and they said that TWG, TGV deletes and fuel pump won't do much to improve performance due to the small turbo. What is your take on that? It sounds to me that you guys believe that it will help or if not at least set me up for a turbo upgrade in the future without sacrificing current engine/turbo integrity.

They recommended 20G, injectors, fuel pump and Protune(duh). But you guys seem to be so damn knowledgeable, I'm having a hard time believing that they are telling me(through FB I should add) It just seems to me that upgrading all the stuff you guys recommended will be necessary to consider a bigger turbo. I'm starting to sway to maybe upgrading to a new turbo is on the horizon now.

 

[HolyCrapItsFast]

Well they are mostly right... :lol: We threw allot of information at you and most of it was optional and with the expectation of a turbo upgrade in mind. Much of what we suggested will set you up for a larger turbo but will also complement the one you have now. So some of the stuff we mention won't do allot for performance initially but it will set you up for a better stage 2 protune and then later if you decide to upgrade your turbo. I have seen too many times in the past where IDC's, on a stage two car with stock fuel pump, were just way to high and I believe this to be a precautionary measure and not a performance upgrade. TGV deletes will give you gains no matter what turbo you have. How much gain? I don't know. Pretty much anything you can do to improve flow will give you gains regardless of the turbo you use. It's just that some of them are not really worth doing unless you upgrade the turbo at the same time. The key is to pick all your components to match and it would be worth it to do everything at one time.

As for headers on a stock turbo, I don't think it will complement things much. It may even degrade performance because if you don't get it right you will drastically change the flow characteristics of the exhaust gases and that will have profound effects on how the turbo responds. If you don't know what you are doing here, it is a crap shoot as to whether you are doing a good thing or not.

Just stick with a stage 2 and a protune and I think you will be very happy for a while. At the very least the fuel pump is highly recommended. The TGV's are optional at this point and everything else will only set you up for a larger turbo later on so not necessary now. The thing that is going to give you the most gain is the protune and Cobb of Plano should be the ones to do it.

My $.02 :tup:

 

[SirMyztiq]

The intake got here today and I installed it right away. The idling issue still persists so I'm going to hit up Rek for a MAF to check that off. I really appreciate y'alls time and expertise!

 

[SirMyztiq]

Well they are mostly right... :lol: We threw allot of information at you and most of it was optional and with the expectation of a turbo upgrade in mind. Much of what we suggested will set you up for a larger turbo but will also complement the one you have now. So some of the stuff we mention won't do allot for performance initially but it will set you up for a better stage 2 protune and then later if you decide to upgrade your turbo. I have seen too many times in the past where IDC's, on a stage two car with stock fuel pump, were just way to high and I believe this to be a precautionary measure and not a performance upgrade. TGV deletes will give you gains no matter what turbo you have. How much gain? I don't know. Pretty much anything you can do to improve flow will give you gains regardless of the turbo you use. It's just that some of them are not really worth doing unless you upgrade the turbo at the same time. The key is to pick all your components to match and it would be worth it to do everything at one time.

As for headers on a stock turbo, I don't think it will complement things much. It may even degrade performance because if you don't get it right you will drastically change the flow characteristics of the exhaust gases and that will have profound effects on how the turbo responds. If you don't know what you are doing here, it is a crap shoot as to whether you are doing a good thing or not.

Just stick with a stage 2 and a protune and I think you will be very happy for a while. At the very least the fuel pump is highly recommended. The TGV's are optional at this point and everything else will only set you up for a larger turbo later on so not necessary now. The thing that is going to give you the most gain is the protune and Cobb of Plano should be the ones to do it.

My $.02 :tup:

You're right. I'm trying to build Rome in a day here and I got caught up in the excitement. I think I'm going to go for the DWorks pump, TGV deletes, meth/water injection and a Protune to tide me over for now. I'm not so hot on the Greddy Evo2 exhaust and Cobb downpipe. I'm consider a true 3" piece. I used to run Tanabe in my last STi and loved it. So that is an option. Besides, there are some other things the car needs. Like the trims along both quarter panels. Where the heck do I get something like that?

I also want to slap on a Short Shifter and some upgrades in the stereo. I'm going to take things slow, maybe get something every month or so to make sure that I do my research before just trying to jump on everything at once. I'm pretty convinced that I want to go with a turbo upgrade so there lots of research to do on that. Plus I know I can count on you guys for some sage advice

The focus now is to get this idling issue fixed and finish up my maintenance work. Replacing the brake lines, check the pads, bleed the brake lines, coolant and I'm not looking forward to replacing the timing belt...it looks quite painful and if it is anything like replacing the one on my brother's hatch then damn. And we all know STi's like to make things as hard as possible.

I'm trying to become a sponsor as soon as possible. Just waiting to sneak my GFs card b/c Paypal is being stupid with me right now

 

[HolyCrapItsFast]

You're right. I'm trying to build Rome in a day here and I got caught up in the excitement. I think I'm going to go for the DWorks pump, TGV deletes, meth/water injection and a Protune to tide me over for now. I'm not so hot on the Greddy Evo2 exhaust and Cobb downpipe. I'm consider a true 3" piece. I used to run Tanabe in my last STi and loved it. So that is an option. Besides, there are some other things the car needs. Like the trims along both quarter panels. Where the heck do I get something like that?

I also want to slap on a Short Shifter and some upgrades in the stereo. I'm going to take things slow, maybe get something every month or so to make sure that I do my research before just trying to jump on everything at once. I'm pretty convinced that I want to go with a turbo upgrade so there lots of research to do on that. Plus I know I can count on you guys for some sage advice

The focus now is to get this idling issue fixed and finish up my maintenance work. Replacing the brake lines, check the pads, bleed the brake lines, coolant and I'm not looking forward to replacing the timing belt...it looks quite painful and if it is anything like replacing the one on my brother's hatch then damn. And we all know STi's like to make things as hard as possible.

I'm trying to become a sponsor as soon as possible. Just waiting to sneak my GFs card b/c Paypal is being stupid with me right now

Do yourself a favor... Don't attempt the timing belt with out first reading the shop manual. Severe damage can ensue if you do it wrong :tup:

http://www.igotasti.com/vBforum/showthread.php?1227-STi-Manuals-2004-2008

 

[SirMyztiq]

Do yourself a favor... Don't attempt the timing belt with out first reading the shop manual. Severe damage can ensue if you do it wrong :tup:

http://www.igotasti.com/vBforum/showthread.php?1227-STi-Manuals-2004-2008

Good deal. I found that thread late last night and I've been looking through it. :tup:

 

[jswansti]

Im doing my timing belt after winter. Gonna have a shop do it cuz I don't trust myself! Props to the guys who do it on their own though!

 

[SirMyztiq]

Here is an update: So my car still has a rough idle. It can get pretty bad at times. I'm waiting to hear from Rek about the MAF sensor to scratch that out of the "potential" list. However, since yesterday the car has been throwing mass misfire codes at me. I've cleared them and there was the "emissions leak" code mixed but I'm getting misfires on all cylinders. Sometimes not on one, sometimes on just two of them. They aren't consistent, at least not that I've noticed. Can a bad MAF or a leak I haven't found cause such misfires? The temperatures have dropped in the last couple of days so maybe that could be a factor.

I recently changed my spark plugs and went with one-step colder plugs bc I was planning for that Protune. I did a fair amount of research and I came away with the idea that colder plugs wouldn't cause these kinds of issues. I will also add that there is a PFFE CEL.

 

[SirMyztiq]

To add: I changed the plugs last Sunday I believe. The day i stripped the torx note on the injector. The issues began happening last night after I pushed her a little harder down a straight road. I got tempted and went WOT today and it caused the misfires. I know, foolish

 

[SirMyztiq]

Bubba:

The problem I was having is similar to yours. After I went stage II I was getting a really rough idle and an "emissions leak detected error" I checked for leaks and replaced the CAI I was getting and with a short ram and still no luck. My A/F Correction was really bad at idle, almost at 25 all the time while idle and sometimes while at highway speeds. I did some logging and it can be found somewhere in this thread.

Currently I'm throwing misfires on all my cylinders. Both times it came after I pushed her a little. I changed my spark plugs last Sunday to one-stop colder plugs b/c I was getting ready for a Protune but I wonder if that has anything to do with it. Currently Rek is being generous enough to send me a working MAF to trouble shoot that to see if that is the root of the problem right now. The bad idling seems a lot worse now after I changed the spark plugs.

I hope this helps! I haven't visited the other site but the guys here have been beyond helpful!