'02 wrx engine detonating and rattling

[mrbledsoe08]

My '02 WRX has been making some valve rattling and detonating noises for a little while.. It happens when under 1/2 to full throttle acceleration. I have also noticed that sometimes it will pop back through the intake every now and then. I have changed the plugs, air filter, and fuel filter. On my A/F ratio gauge everything seems fine under throttle and am getting 14 psi boost. I do not have any check engine codes on at all. All is stock except for a turboXS bov. I am assuming that the timing belt may be stretched some. It is definatly time to change it. I have 108k miles on it. Any other ideas??

[Donkey]

I really doubt it is backfiring. Modern fuel injected cars dont backfire. It is probably the bov.

[Impreza2.0]

TurboXS valves leak. I have one. It leaks. It sounds awesome, but it makes a whining noise as soon as it gets any significant pressure under it. I run 17psi peak boost. There are a few that don't leak, TurboXS is one that just does though. Yours is a "Hybrid RFL" (RFL-H for WRX/STi), correct?

[mrbledsoe08]

Yes it is a RFL-H. When i bought the car off of the owner, he gave me 2 bov's. One was the turboXS and the other was a HKS SSV. I may try the HKS today, and if no success I will install the factory back on. It sucks driving around half thottle.

[yamaha_rider619]

Dont use the hks, just put the factory bpv back on.

[Impreza2.0]

x10... HKS is just as notorious for leakage. There's a whining that follows boost pressure, the higher the boost, the higher the pitch of the whine. Some people think it sounds great, some recognize it as a loss of boost. The loss of boost is not worth that sound. A properly installed BOV with no leaks will still have the inherant leaning-out issue under throttle, but it will only create that one issue. It is then harder to diagnose for those unaware of the facts.

If you want a good aftermarket bypass valve, Forge, TurboSmart, Tial, Perrin, those are OK. Tial is hard to install because it does not have a flange for the stock elbow like your TXS valve. It uses a straight pipe, like the HKS.

again, x10 that the HKS is not a solution to a bad TXS valve.
i'd spend the $90 and get a Forge recirculating bypass valve and call it a day.
sell the other two valves for $45 a piece and have what you wanted to begin with... boost you can feel.

[patrick4588]

valve tick? when was the last time the valves were adjusted?

[2002SubieWRX]

valve tick? when was the last time the valves were adjusted?

Correct me if I'm wrong, but if the valves are loose wouldn't they tick throughout the RPM range and not only under medium to full throttle?

I have what may be a similar issue with my '02 that has 146,xxx miles. I have owned the car since it had 117,xxx and don't know much of the maintenance from before I purchased it. My issue is more of a rattling type noise under hard(er) acceleration that seams to be coming from the turbo.

My thought is this: I took the exhaust off to change my clutch/pressure plate/flywheel but didn't replace the turbo-downpipe gasket so after-turbo exhaust is leaking through a poorly sealed gasket. I noticed it after the clutch replacement, went back and re-torqued the exhaust bolts to spec but it didnt' fix the problem.

I'll be installing new GrimmSpeed gaskets when I install my new GrimmSpeed uppipe and I'm hopeful the new gaskets (%22 thicker than OEM) will eliminate the rattling noise. I'll post on it when I get them in.

[Anub1s]

x10... HKS is just as notorious for leakage. There's a whining that follows boost pressure, the higher the boost, the higher the pitch of the whine. Some people think it sounds great, some recognize it as a loss of boost. The loss of boost is not worth that sound. A properly installed BOV with no leaks will still have the inherant leaning-out issue under throttle, but it will only create that one issue. It is then harder to diagnose for those unaware of the facts.

If you want a good aftermarket bypass valve, Forge, TurboSmart, Tial, Perrin, those are OK. Tial is hard to install because it does not have a flange for the stock elbow like your TXS valve. It uses a straight pipe, like the HKS.

again, x10 that the HKS is not a solution to a bad TXS valve.
i'd spend the $90 and get a Forge recirculating bypass valve and call it a day.
sell the other two valves for $45 a piece and have what you wanted to begin with... boost you can feel.

Or, you know, save money and run the stock BPV which is what the car works best with, but whatever.

[Impreza2.0]

I'm running 18psi. I don't know about you guys, but that's above the pressure limit for normal operation on the stock BPV. I wouldn't trust it.
I managed to cure the leaks in my TXS hybrid, and it works flawlessly. It's got stepped venting, so it only vents atmospherically when shifting at high RPMs, which does nothing harmful. It can stink a little, and I would go back the the GFB Hybrid, but it is slower. I am waiting to get a new IC before I shop for a valve.

[zax]

I'm running 18psi. I don't know about you guys, but that's above the pressure limit for normal operation on the stock BPV. I wouldn't trust it.

2002-2007 BPVs are supposedly good to 20PSI. Remember, the STi and WRX BPV are essentially the same.

[Impreza2.0]

20? I hear 18 from everyone... I still prefer the peace of mind that comes from a billet precision manufactured device with option of tuning release pressure, one with a lighter piston which reacts faster with less surge. I see where you are going, that the OEM valve is ideal, and already installed, so there is little reason to ever touch it unless other work requires it.

If you don't have one, there are simply affordable options with improved construction, ie; Forge bypass valve, superior construction, adjustability, warranty, excellent results in use... $75. There are none available cheaper used because anyone who has bought one quietly moves on to other mods, because they work correctly without any fuss. TurboXS units take fuss. Quite a bit if you got one that was knocked around in shipping, because they will leak fiercely without a good rebuild before installation. HKS units aren't bad as far as shipping damage, but they require a flange adapter which is tough to get perfect, and have a very delicate diaphragm compared to most vertically mounted piston units. Synapse (Synchronic) is similar to HKS, is better machined, but suffers the issue it begs to offer a solution to. TurboSmart is very well machined, almost never suffers from any issue other than user ignorance (setting too much VTA). Perrin is a set it and forget it valve with no difference in operation over stock besides adjustability and a tricky mount. Go Fast Bits seems the finest in terms of construction, overbuilt to death like Tial. They also offer the variety of vent styles TurboXS used to offer. TurboXS has made their BOVs more compact, and less rebuildable. IDL that too much, it makes working on them very tedious.

[zax]

20? I hear 18 from everyone... I still prefer the peace of mind that comes from a billet precision manufactured device with option of tuning release pressure, one with a lighter piston which reacts faster with less surge. I see where you are going, that the OEM valve is ideal, and already installed, so there is little reason to ever touch it unless other work requires it.

If you don't have one, there are simply affordable options with improved construction, ie; Forge bypass valve, superior construction, adjustability, warranty, excellent results in use... $75. There are none available cheaper used because anyone who has bought one quietly moves on to other mods, because they work correctly without any fuss. TurboXS units take fuss. Quite a bit if you got one that was knocked around in shipping, because they will leak fiercely without a good rebuild before installation. HKS units aren't bad as far as shipping damage, but they require a flange adapter which is tough to get perfect, and have a very delicate diaphragm compared to most vertically mounted piston units. Synapse (Synchronic) is similar to HKS, is better machined, but suffers the issue it begs to offer a solution to. TurboSmart is very well machined, almost never suffers from any issue other than user ignorance (setting too much VTA). Perrin is a set it and forget it valve with no difference in operation over stock besides adjustability and a tricky mount. Go Fast Bits seems the finest in terms of construction, overbuilt to death like Tial. They also offer the variety of vent styles TurboXS used to offer. TurboXS has made their BOVs more compact, and less rebuildable. IDL that too much, it makes working on them very tedious.

Best solution is an EJ207 BPV. Those will hold 30 PSI and they're OEM.

[mrbledsoe08]

Well, heres a little update. After reading that the turboXS may be the problem, i tried the HKS just for the heck of it. I drove it prolly 5 miles since then, with no problems. I also cleaned the MAF and throttle body while I was at it. I did notice that boost would spike up to 14 psi and then start slowly leaking off to 11, giving me the idea that the HKS is a P.O.S. So, with that said.. I am prolly gonna junk em' both and go back to factory shortly. I dont have to have a aftermarket bov as it stock, just like the sound.

As for the valve tick.. its not like a valve out of adjustment. It sounded like your running horrible 87 gas in a high compression engine.

[Impreza2.0]

Yep, well, I doubt you'd find a 207 valve for less than a decent bypass style aftermarket one... Forge's one is the one I recommended due to it being nearly identical in every way to the stocker, except it is BUILT FAR BETTER.

I think the idea here is to NOT have stamped junk to replace stamped junk.

A dirty MAF will screw up a lot. So will an HKS valve... like I said earlier.

Forge states 50psi max boost. GFB states 50psi, TurboXS states the same. My TXS valve works flawlessly, but I tore it apart and resealed it at all the threads, used a new gsaket (prime location for a boost leak), and Grade 10 hardware to bolt it to the IC with. It doesn't hurt to put a bead of stops-leaks in the
ring seat where the elbow bolts up... that is poorly finished on all the TXS BOVs I have seen (for Subarus at least)
It sounds like you have it handled though... if you do go trying to find an OEM valve, most used ones are in great shape, since people trash them for all the wrong reasons almost as a rule.