My Stock Turbo Intermittently Works...PLEASE HELP

[_mpizzle_]

I have a 2003 Subaru WRX and my stock turbo doesn't spool every time I drive it or "need" it. Sometimes the turbo will kick in at about 3500 rpms and other times it doesn't do anything, and even when it's idling. I know this because I can obviously hear the blow off valve when it does spool. Any idea what it could be? I am pretty new to these cars so I don't know much. The other thing is that the clutch is about to go out and I will be getting replaced very soon. When I get the car going and the boost does actually kick in, I lose the clutch at about 4500-5500 rpms usually because it can't hold the extra power. Could it be something to do with that? Maybe some sort of safety switch by an internal computer keeping the turbo from spooling because of the lost in power with that worn down clutch..?? I am not sure. Please help me out!

[MainFrame]

What do you mean "even when it's idling"? The turbo cannot spool without the engine being under load. Also, your car shouldn't have a blow off valve, unless someone changed out the stock bypass valve. What has been done to the car? When did this problem start? Also, what boost pressure does it achieve when it seems to be working?

[EndlessSea]

in regards to your problem. if its an intermittent boost problem, it could be the factory boost controller system is malfunctioning. or it could be your aftermarket bov(if you have one, you said you can hear it so im assuming here) is causing a boost leak. i had that same problem on an sr20det 240sx i had. intermittent boost, low max boost. turned out my bov wasnt holding the pressure and venting boost at full throttle.

1. you shouldnt be able to hear the bpv, unless it has an intake on it. if it has an aftermarket bov. buy a stock one and ditch that aftermarket junk.

2. does it have the stock turbo on it? what other mods have been done? do you have a boost gauge on it to monitor if your turbo is boosting? the stock td04 should spool really really fast and hold about 13.6psi through the mid rpm ranges if stock. its not gonna pull like a freight train from 1500rpm. but by around 2500-3000 it should be pulling pretty good and if it does indeed have an aftermarket intake you'll hear the turbo spooling, and the factory bpv will sound off slightly with an open intake

[RogerSteadman]

before you change your clutch out. read this.
this is from EXEDY themselves in thier TECH DEPT.

SOURCE: Subaru Tech Tips
TITLE: Clutch Appears to Be Slipping
APPLIES TO: Impreza WRX
SERVICE TIP:
If you encounter an Impreza WRX with a customer concern that the vehicle's clutch slips under hard acceleration but drives normally under light acceleration, it might not be the clutch that's the problem. Before you yank the transmission to get to the clutch, put the car on the lift. Start the engine and put it in gear. Release the clutch and see if all four wheels are turning. If they are not, inspect the one that is not turning. The Technical Support Line has received a couple of calls with the above concern and in both cases the retaining clip on the inner end of the rear axle shaft has come off. This allows the axle shaft to move outward slightly to disengage from the side gear of the rear differential but, the wheel bearing retainer assembly will not allow the axle to come out completely. Since these vehicles have a limited slip rear differential, there is enough drag on the axle to move the car under light acceleration but not under heavy acceleration.
The repair is simple. Just push the axle inward and it should reengage the retaining clip. If this procedure does not work, then you will need to remove the rear differential cover to re-install the clip and/or examine the axle. If the vehicle is an Impreza WRX STi, you might find that the vehicle won't move unless the DCCD is in the 'Manual' mode. In this case the cause may be a failed rear axle shaft or joint assembly

[Ruh Roh]

good info to know^

[RogerSteadman]

thats how i found out that my differential was messed up, but btw if the front tire(s) dont spin its the front diff which is not an easy fix, i still havent figured out how, the rear takes like 5 mins

[Heide264]

What all has been done to the car? When you say "obviously hear the blow off valve", it hints that the car has been messed with.

I don't think your turbo is going to work "even when idling" either. Doesn't quite work like that. Are you revving your engine and expecting your turbo to do something?

I think we may just have some common terms switched up here. Can you clarify at all?

[_mpizzle_]

REPLY ALL: I apologize for the misunderstanding. When I said the turbo doesn't spool when idling I meant when I rev the engine when it is in neutral, it doesn't but then other times it does. It is like the turbo can't make up its mind if it wants to spool or not. The car definitely has an aftermarket blowoff valve that my buddy says was actually really nice. I just bought the car, the boost was working the day that I got the car all 80 miles to my house. The dumbass I bought it from did not even know what mods were on the car because he thought the whole thing was stock. From what I can tell, the only mods are the exhaust, downpipe, and the blow off valve. The turbo is TD04 stock.

[_mpizzle_]

in regards to your problem. if its an intermittent boost problem, it could be the factory boost controller system is malfunctioning. or it could be your aftermarket bov(if you have one, you said you can hear it so im assuming here) is causing a boost leak. i had that same problem on an sr20det 240sx i had. intermittent boost, low max boost. turned out my bov wasnt holding the pressure and venting boost at full throttle.

1. you shouldnt be able to hear the bpv, unless it has an intake on it. if it has an aftermarket bov. buy a stock one and ditch that aftermarket junk.

2. does it have the stock turbo on it? what other mods have been done? do you have a boost gauge on it to monitor if your turbo is boosting? the stock td04 should spool really really fast and hold about 13.6psi through the mid rpm ranges if stock. its not gonna pull like a freight train from 1500rpm. but by around 2500-3000 it should be pulling pretty good and if it does indeed have an aftermarket intake you'll hear the turbo spooling, and the factory bpv will sound off slightly with an open intake

Look at my reply below and that might be able to answer those questions. Why shouldn't I be able to hear the valve? The car starts spooling at about 3000 and fully spools around 4000, and when i shift, I hear that loud blow off valve. I agree that the max boost should be around 14, but I am not 100%. I have not had time to play around yet because of the clutch slipping when the boost kicks in. The intake looks bone stock to me though. I have not installed a boost gauge yet because I don't have the money now.

[_mpizzle_]

before you change your clutch out. read this.
this is from EXEDY themselves in thier TECH DEPT.

SOURCE: Subaru Tech Tips
TITLE: Clutch Appears to Be Slipping
APPLIES TO: Impreza WRX
SERVICE TIP:
If you encounter an Impreza WRX with a customer concern that the vehicle's clutch slips under hard acceleration but drives normally under light acceleration, it might not be the clutch that's the problem. Before you yank the transmission to get to the clutch, put the car on the lift. Start the engine and put it in gear. Release the clutch and see if all four wheels are turning. If they are not, inspect the one that is not turning. The Technical Support Line has received a couple of calls with the above concern and in both cases the retaining clip on the inner end of the rear axle shaft has come off. This allows the axle shaft to move outward slightly to disengage from the side gear of the rear differential but, the wheel bearing retainer assembly will not allow the axle to come out completely. Since these vehicles have a limited slip rear differential, there is enough drag on the axle to move the car under light acceleration but not under heavy acceleration.
The repair is simple. Just push the axle inward and it should reengage the retaining clip. If this procedure does not work, then you will need to remove the rear differential cover to re-install the clip and/or examine the axle. If the vehicle is an Impreza WRX STi, you might find that the vehicle won't move unless the DCCD is in the 'Manual' mode. In this case the cause may be a failed rear axle shaft or joint assembly

Very good info to know, thank you. I will definitely do that and hopefully that is the issue. But I am pretty sure it is the clutch going out. Sometimes, if I am not being careful I can smell it.

[_mpizzle_]

What all has been done to the car? When you say "obviously hear the blow off valve", it hints that the car has been messed with.

I don't think your turbo is going to work "even when idling" either. Doesn't quite work like that. Are you revving your engine and expecting your turbo to do something?

I think we may just have some common terms switched up here. Can you clarify at all?

Yeah I apologize about that. My post below should clarify that stuff up for you though. From what I can tell the car has aftermarket exhaust, downpipe, and blow off valve and that's it.

[MainFrame]

It is impossible for your turbo to build boost in neutral, it has to be in gear and under load.

[Heide264]

You should post some pictures of the engine bay. Concentrate on the turbo and exhaust right behind it. Be nice to have a better idea for sure what is done to it.

An after market bov isn't ideal on these cars, but it isn't going to cause the issues.

Can you get ahold of somebody with a tactrix cable? Would be nice to get a learning view to see if the tune is having any issues.

You won't build boost while reving the engine. The turbo requires the engine to be under load to output any usable compression.

Otherwise, even if the ECU was pulling boost.. It couldn't pull it further than waste gate spring tension. This would be around 7psi I believe. Up until 7psi, it is all mechanical. Look for driveline (clutch) issues or boost /vacuum leaks.