Leaking BPV?

[Gary1001]

Hey, should the OEM BPV open at around 4-5 psi?

Here is a video.

https://photos.app.goo.gl/3F6VS1XaW25Mf7yg8

I started doing a boost leak test, as soon as any pressure comes on (say 5psi), it starts escaping.

[C-love]

I'm a little new to this vehicle myself, but I believe there needs to be vacuum on that line to hold boost. I pressure tested my IC and BPV out of the vehicle and used a 60ml syringe hooked up to the bpv to hold negative pressure. Obviously less than ideal, but allowed me to rule out any major leaks on my IC and BPV.

What section do you have isolated for the pressure test? Why not leave that line connected as it just goes right back to the TIP?

EDIT: I have a Turbosmart dual port BPV, not sure if the stocker relies on the same principle.

[Gary1001]

I am pressuring from start of the IC (just after the turbo outlet) through the TB. I was going to start at the turbo inlet but didn't have the right piping, I'll look at it tomorrow.

Good idea about the syringe, I'll give it ago.

From my understanding, the recirc tube needs to be disconnected to tell if the BPV is leaking... could be wrong here tho.

Did you have any luck with doing a test in the car?

[C-love]

Hey Gary,

I have not tested in car yet. Additionally, I was wrong last night, all my testing was a bit of a blur as that was at the end of a long day. We had to apply positive pressure to the 4mm line with that syringe in order to pressure test the valve with the IC. This is normally fed to the valve from the IM under boost conditions.

This thread may be helpful to you:

Stock BPV Leak? I may have a cost effective semi-solution...

[MSMS3]

@Gary1001;

It is very rare for the OEM bypass valve to leak at K04 boost levels. If the turbo is holding targeted boost and wastegate duty cycle is as expected, the bypass valve is not leaking.

It is a very elegant design that has proven to hold boost extremely well. Yes, they can fail. No, not very often.

Your boost leak is likely one of the clamps or hoses between the turbo, intercooler, and throttle body. That’s where 99.9% of the leaks occur.

How are you doing your boost leak test? Do you known for sure the loss of boost is from the bypass valve?

[Gary1001]

Originally Posted by MSMS3 @Gary1001; It is very rare for the OEM bypass valve to leak at K04 boost levels. If the turbo is holding targeted boost and wastegate duty cycle is as expected, the bypass valve is not leaking. How are you doing your boost leak test? Do you known for sure the loss of boost is from the bypass valve?

Good to know. I've attached some AP logs, I'm guessing the BPV is ok with these boost targets and WGDC? I think I'm running rich tho, hence the leak testing.

I started the leak test from the hot side of the intercooler - disconnected from the turbo outlet and reconnected that hose to positive pressure. I also just replaced the four major hose clips with T-bolts, MAF sensor, air filter and spark plugs.

When doing a leak test, do you need to open the throttle body to pressure the other side of the BPV?

[C-love]

Originally Posted by Gary1001 Good to know. I've attached some AP logs, I'm guessing the BPV is ok with these boost targets and WGDC? I think I'm running rich tho, hence the leak testing.

What intake are you running Gary?

[Jeff23spl]

you need to have the top and bottom at the same or close pressure when you test for leaks like it is under boost while the engine is running.
if the top isn't receiving boost, for sure the valve will open at low pressure because it is the way it is made to work. (releasing fuel pedal drop the intake pressure connected to bov top while turbo discharge pressure is still high and make it to open.

[MSMS3]

Your BPV is not leaking.

Why do you think you are running rich?

Your AFRs look good to me. With this engine you must run rich (down to the 10s even high 9s under high load, high rpm) for cylinder cooling. It’s part of the engine design to allow fairly aggressive timing at high boost without detonation.

[Gary1001]

It was mainly the long and short term fuel trim, -10 or so when cruising.That and the car has a rough idle and hesitation on acceleration.

The car is completely stock and compression is 172 across the board.

[C-love]

Hey Gary,

I was asking because the speed3 I bought had the mazdaspeed CAI on it. My LTFT's were between 15-20. I ordered the air straightener for it and then they dropped 15 almost instantly, settling around 5.

Have you cleaned the MAF sensor? Logged/checked the forward 02 sensor? What's your plug gap set at? Otherwise I'm starting to suspect it may be a an electrical issue, possibly bad harness or connector?

[MSMS3]

Originally Posted by Gary1001 It was mainly the long and short term fuel trim, -10 or so when cruising.That and the car has a rough idle and hesitation on acceleration. The car is completely stock and compression is 172 across the board.

What plugs, and how are they gapped?

Long term trims are off a little more than expected, but +/- 8 is acceptable.

I agree that I’d your intake is supposed to have an air straightener, it should be used . Trims can be off for that reason.

[C-love]

Originally Posted by MSMS3 I agree that I’d your intake is supposed to have an air straightener, it should be used . Trims can be off for that reason.

For what it's worth I had positive LTFT 15-20 without the straightener. I could smell it was running too rich. I think Gary has negative trims pulling fuel.

[Gary1001]

Originally Posted by C-love For what it's worth I had positive LTFT 15-20 without the straightener. I could smell it was running too rich. I think Gary has negative trims pulling fuel.

Yes, mine are negative.

[Vansquish]

Originally Posted by C-love For what it's worth I had positive LTFT 15-20 without the straightener. I could smell it was running too rich. I think Gary has negative trims pulling fuel.

If you have a positive LTFT, that means your car is running lean and the ECU is adding fuel to the mixture to compensate.

If you have a negative LTFT, that means your car is running rich, and the ECU is reducing the amount of fuel being injected in order to compensate.

Adding an air-straightener will reduce the error rate in MAF readings. If, for whatever reason, the shape of your intake caused your MAF to read incorrectly without the air straightener, you could well have had a situation where the ECU was being tricked into adding fuel because the MAF sensor was reading that more air was entering the engine than there actually was.

[C-love]

Originally Posted by Vansquish Adding an air-straightener will reduce the error rate in MAF readings. If, for whatever reason, the shape of your intake caused your MAF to read incorrectly without the air straightener, you could well have had a situation where the ECU was being tricked into adding fuel because the MAF sensor was reading that more air was entering the engine than there actually was.

Yes I believe that is what commonly happens with the MS / AEM CAI if you are missing the straightener.

[Gary1001]

New NGK Iridium IX Spark Plug LTR7IX-11 gapped at .28.

I pulled the plugs after 1000km. Pic attached. It looked like it was rich but I'm a noobie so could be off.

[Jeff23spl]

the plugs doesn't look bad, if there is something, it is looking a bit lean but it depends under which condition you last ran them just before pulling them out.

You cannot really compare ltft of 2 cars since there is a lot of different parameters... ....but being at 15-20 mean there is something wrong with either your maf reading or your maf cal....possible leak pre-turbo

[MSMS3]

Maybe I’m off, here, but I thought that negative trims pointed to a post turbo leak or a leak on the exhaust side between the turbo and the O2 sensor.

Or, simply a dirty MAF sensor or it having been replaced with an aftermarket sensor. This is one part that must be genuine OEM to get accurate readings.

Plugs look fine. I’d have gapped them tighter at .026”, but the slight difference is not relevant here.

[Jeff23spl]

Originally Posted by MSMS3 Maybe I’m off, here, but I thought that negative trims pointed to a post turbo leak or a leak on the exhaust side between the turbo and the O2 sensor.

I was answering to the other with positive LTFT....
I agree with you for the post turbo leak and gegative trim but maybe not for the exaust leak.
o2 reading air coming from outside of the exhaust pipe will think it is lean and add fuel with positive trim to faulty compensate.