Hey everyone! I haven't done much posting on here in a while... I hope everyone is doing well. I keep telling myself that I'm going to try and get more involved in the community, but alas, work and travel have left me a recluse. I hate to be the d-bag who only shows up when he's having problems, but I'm hoping that maybe some folks on here could lend some advice in regard to what I'm doing. I have a 2004 wrx wagon equipped with a Deadbolt ported and coated "small" 16G, 650 injectors, STi topmount, and Accessport that Scott (who was awesome, btw) tuned last August. It put down 291 whp and 295 wtq the day it was tuned, and ran like a raped ape for about six months. After some time, I noticed that it seemed a little bit slower. At first I thought this might be in my head, but at the dyno day Topspeed had early last June (or was is last May?), my suspicions were confirmed; it put down 270 whp, and 270ish wtq, and it took a couple of pulls on the dyno before it worked up to that number. This summer, the car has seemed to diminish even more in terms of power, and it is struggling to hit target boost of @19psi. It used to always pull to 19 psi in fourth, but now it only happen on rare occasions (now I seem to come about 2 PSI short). The car will hit target in 5th, but even then it seems to take some extended driving before it decides that it wants to do that. Oddly, though, the car pulls smoothly, and I haven't noticed it smoking. I've finally gotten time to start tearing into the car. I'm not ready to write the motor off just yet, but I definitely want to find out if I have a larger problem before I spend money on the new timing belt, tensioner, and water pump that I was planning to put on when it hits the 90k mile mark. (It has about 85k on it right now.) I suppose the best place to start is with a boost leak test. First, I made a tester like the one shown in this thread: http://forums.nasioc.com/forums/showthread.php?t=1703459 I've done the turbo to intercooler test. I found a couple of tiny leaks, and fixed them. Drove the car, no change. Now, I'm about to move onto the next step, which will consist of capping the throttle body, and pressurizing the intake manifold. I noticed that in the thread I posted above, it says to, "Connect purge solenoid ports on the manifold." (In other words, cap them off.) I am wondering, what happens if I leave those alone, and run the test without plugging them? Wouldn't I want to know if any of those lines are leaking as well, or am I missing something? Would I end up losing manifold pressure to the intake tube? The above being said, perhaps I'm wasting time by doing the intercooler and manifold separately. When looking at other threads, I've noticed that some people pressurize the the intake tube itself. However some threads depicting those methods say that one should, "Remove the hose from the turbo inlet tube that goes to the purge valve and Plug the nipple'," as well as, "Slip the small hose going from the intake manifold to the purge valve off of the mainfold nipple and plug the metal manifold nipple." (This info was pulled from: http://forums.nasioc.com/forums/showthread.php?t=1445778 ) Other than the buzzing sound, what happens if the aforementioned hoses are left connected? Do most of you follow a method similar to the last post? Finally... I'm left wondering what you would recommend for my next step if I do not manage to find anymore leaks. I imagine a compression test is the next logical step, but then what? Throw in the towel and let the wizards at Topspeed datalog it? (This is something I would try... but I have no laptop.) Do any of my problems seem indicative of a known issue? Okay. Apologies for the novel- I just wanted to be as specific as possible. Many thanks if you've read this far. And if Scott or any of the Topspeed guys have some advice, double thanks to you. Maybe at the very least I can cross out any obvious issues before I put the car back in your hands. Sincerely, Jonathan
It has. I might be forgetting some things, but I think I did plugs (which were switched out again for a colder range right at 75k), accessory belts, PCV valve, gearbox oil, rear differential oil, flushed the brake and clutch fluid, replaced the thermostat, and did a coolant change with conditioner. The new plugs are NGK one range colder than stock platinums, and I can't detect any misfires. Likewise, there are no codes. If it weren't for the fact I know how it used to pull, I wouldn't think anything is wrong. I do have low EGTS... hard romps only push the gauge up to 1250 degrees. I've always attributed this to a craptastic gauge- it's a VDO with the shielded probe, and the temps have acted pretty much the same since the gauge was installed last Christmas.
Well, I pressurized the manifold today and found... nothing. At least nothing in terms of boost leaks. I pressurized it up to about 20 PSI, and listened carefully. I could hear the sound of air flowing within the engine... I imagine this was simply because it probably stopped with at least a few valves open, correct? I could find no leaks around the manifold region, and no hissing sounds from near the injectors. If I completely closed the air regulator, boost pressure would bleed back down to zero within the span of about 10 seconds. There was ONE issue I found... the hose running from the stock BPV to the aftermarket silicon inlet was no longer connected very well. I reattached it solidly with a couple of clamps, put her back together, reset the ECU and took her for a drive. I've never received any check engine lights indicating a lean condition, and I'm not certain there was an intake leak, but surprisingly, the car DOES run noticeably better... I can hear the aftermarket electronic BCS working harder to regulate boost than it did, and after a few pulls I was hitting target boost in 4th and 5th. I am using the stock Lamco boost gauge, but live boost on my AP was indicating that I was momentarily hitting 18.3 (where the Version 1 AP maxes out) or higher in 3rd. Then again... maybe tonight's lower humidity and temps were the result of this. I'll be interested to see how it does on a warm day. So I wonder... Can an intake leak actually cause a low boost condition? I'm wondering if my ECU was confused by the possibility of unmetered air. Likewise, can the ECU, at will, cut back boost slightly because of atmospheric conditions? Or is it an all or nothing sort of system? This is why I've never attempted to tune my car... I just don't understand everything the ECU is capable of doing.
If the "aftermarket electronic boost control solenoid" you are referring to is a Perrin EBCS, they have an EXTREMELY high failure rate... When they fail, they INTERMITTENTLY give low boost... Siegel
Hey, Scott! I appreciate the reply. The aftermarket solenoid is actually the in house brand that Mach V Motorsports was selling. When one of these starts causing problems, is it a case where it drops down to mechanical boost pressure, or it can cause you to fall short by 2-3 psi? Is there anyway that the solenoid can be tested? Thanks again for taking the time to reply. If you'd rather I called, just let me know. Then again, maybe I ought to just buck up and bring er' to your shop.
FWIW, just thought I'd provide and update. I spoke with Scott about the possibility of the Solenoid going bad. As mentioned, I bought it through Mach V Motorsports, and it was labeled as their "in house" brand. I called them and asked a couple of questions about their source for these units, and while the guy on the phone wouldn't disclose exactly who builds them, he did say that "it was exactly the same as the Prodrive units." Well... reading between the lines there, I have doubts that the unit is failing. I was going to replace the unit anyway and have Scott do a touch up tune and double check everything just to be safe, but Topspeed is out of Prodrive solenoids at the moment. I guess I'll hold off and go through everything on the car before taking it to the shop again. Regardless, if you read this Scott, I sincerely appreciate your help. As for the car itself... after going back through the inlet and intercooler tubes, it is running GREAT. It pulls harder than it has in a few months now, and has been hitting target boost over the past couple of days- sometimes even in third. (It hasn't done that since last winter.) Maybe, just maybe, fixing the possible inlet leak has helped the ECU sort matters and become happy with what it is seeing again. Even if the ECU doesn't necessarily lower boost targets, if it senses lean, rich, or knock conditions, the engine can have more trouble pulling up to those targets, right? Regardless, I'm going to do a leakdown test within a couple of weeks and make sure all is okay in that regard. I have found another PIA issue, though. I've heard a slight rattling, and in the process of going through the car, I discovered that the heat shield on the STi uppipe has come loose. :unamused: Guess I'll have to take the whole friggin pipe off to fix that. Maybe I'll just upgrade to a Grimmspeed or similar piece. As always, it comes down to $$$$$$$$$$$$$$$$$$$$$$$$$. Damn money pit.
Well glad it seems to be coming back around...I did have very intermittent issues with my Perrin EBCS but not hiccup yet on the prodrive despite the prodrive looking much less quality than the perrin.
I believe the Prodrive is an OEM solenoid on some European car, so it's really intended for automotive use. The Perrin is basically a McMastercarr solenoid and I believe intended for use in an indoor environment. I do know that Perrin changed solenoids at some point, but I don't know when or if the new ones are better... Siegel
My Grainger EBCS is for sale. It works just fine and is made better than the Perrin. Has metal barbs too. $20 shipped.
I haven't gotten to closely inspect the upper half of the shield (the one closest to the turbo), but I know the lower half of the shield (closest to the manifold) has broken loose completely. I can grab it and move it around with my hand. In other words, the half of the shield furthest from the camera in this picture has come loose: I ran across some random Nasioc thread where someone stated that the rattling of a loose uppipe shield was causing their knock sensor to detect false knock. I don't know if I put any faith in that story or not. That would have to be one sensitive sensor.
That is 100% possible. Knock sensors are very sensitive to metal to metal impact sounds. Christian from Cobb's first question when discussing inappropriate indicated knock is always loose heat shields. Siegel
I'm going to try and get that uppipe out of there this weekend. Right now the closest thing I have to a garage is a pecan tree, so I should have tons of fun rolling around in the mud. I'm currently debating between cutting the shields off of the current uppipe and heat wrapping it, or buying an aftermarket flex pipe. If I was to get, say, the Grimmspeed pipe, do you think the change in flow would be enough to cause problems with my current protune? Once I get through all of these small things, do a leakdown test, and change the timing belt, I was going to bring it in for some touch up tuning and a general checkup. With finances being tight, though, it might not be until around Christmas when I can finally do all of that. I'd rather not fubar the engine in the meantime. And Scott, if you read this, if another uppipe is a safe upgrade, do you know if ya'll happen to have any uppipes in stock at the moment? No need to go out of the way to find out... I can just call on Saturday if the need arises.
my car is basically doing the same thing..no numbers to prove it but it has lost .2 to .4 tenths in the quarter mile and doesnt hold the high rpm boost that it used to..my car has almost 100 000 miles on it now and i haven't done much maintenence since 60k
i was about to make a post about this also but my aftermarket cusco shield is very very loose and maybe i'll pull the top mount off and re tighten it
^^^ It will be interesting to see if it helps your problem. I STILL haven't had time to fix mine. Right after I made the previous posts, work at my regular job was busy (teaching), and I was trying to get ready for the Road Atlanta weekend. When it finally looked like my afternoons were going to be free again, my afternoon jobs picked up (shade tree auto mechanic). Ugh. I'm hoping that I can at least get hold of some new gaskets this weekend. You know how it goes... the plumber's sink leaks, etc. etc. I'll update on whether the shield seemed to have an effect. I spoke with someone who suggested putting some electrical parts cleaner through the solenoid. I might give that a try as well- I figure it can't really hurt anything. If none of that helps, I'll move on to a leakdown test. If THAT doesn't show any problems, I'm setting the car on fire and/or using it for target practice. There's a 300ZX Twin Turbo that's been calling my name, and I'm finding myself more and more tempted to give in.