Best way of testing for a leaky BOV??

As the title says really, what is the best way of testing if your BOV is leaking? Someone told me the best way is to disconnect the Vac hose from the bottom and plug it with something, ie a small screwdriver, and start the car, if it runs any different to with the BOV connected then the BOV is faulty.

Didnt like the sound of that at first so thought id ask on here. Its a HKS SSQV by the way.

I had a leaky BOV that took me absolutely ages to find, but the car ran fine when it was started up ( I was losing peak boost). I'd remove the valve completely, blank off the connections and take the car out for a drive.

What problem do you think it's causing?

I've not heard this method before, and personally cant see how it will help - if it leaks, its going to leak whether the vacuum hose is connected or not, surely?

After all, it wont be cause of the vacuum hose that its leaking...

I had a leaky BOV that took me absolutely ages to find, but the car ran fine when it was started up ( I was losing peak boost). I'd remove the valve completely, blank off the connections and take the car out for a drive.

 

What problem do you think it's causing?

http://www.mkivsupra.net/vbb/showthread.php?t=72959

I've not heard this method before, and personally cant see how it will help - if it leaks, its going to leak whether the vacuum hose is connected or not, surely?

 

After all, it wont be cause of the vacuum hose that its leaking...

My mate thinks the leak is causing air to return to the intake side of the engine cos of the leak, therefore causing a low idle and a drop in oil pressure, the turbo also isnt boosting properly. By disconnecting the vac hose, the return to the engine is removed and therefore the excess air cant affect the engine.

At least thats how i understood his explanation.

Gareth you can do what you mate said, basically diconnect the vac hose from the BOV the small 3-5mm one and block this off, so basically it wont dump anymore, and take the car for a drive and see how it boosts. Regardless of what people say, this is the best way to know if your BOV is leaking and there are no detremental effects on the car as long as its just to 'test' for a short period,

The purpose of the BOV is to prevent large pressure spikes in the intake pipes when the throttle plate is closed while boosting, preventing the turbo from surging and obviously has a purpose, so only do this for a very short peroiod of time, maybe a couple of runs and see if you notice a difference.

By disconnecting the vac hose, the return to the engine is removed and therefore the excess air cant affect the engine.

I don't really understand this. At idle you are obvious off-boost so the entire intake system is non-pressurised so there can't be "excess air" going in to the engine. If there's a major leak to atmosphere then the idle could be affected though. My old apexi unit was leaking so badly I could only get 0.55 bar of boost with double decat but the idle was completely unaffected.

wkd, what youve suggested isnt the 'best' way - the only way to actually test for a leak is to do what Stevie said - take it off and blank where it sits!

wkd, what youve suggested isnt the 'best' way - the only way to actually test for a leak is to do what Stevie said - take it off and blank where it sits!

Thats pretty much the same thing, you are still preventing the BOV from surging, the effects are the same, theres plenty of ways to skin a cat

garath what happened to cant afford a supra because iam buying a house!!!

you have a boost leak in your intake manifold , you probley have change the fuel system because you are running a single. which means you have taken the intake manifold of in the past .turn the car on and spray wd40 on the intake side along where it attaches to the lower runner , and listen to the note of the car change .You can pinpoint where is is leaking this way , then try and tighten the nut in those locations. I would check your ic piping first , ususally doggy silicon hoses and clamps . Then look at the bov, i would say you have a boost leak on the pipe work or fmic ... bov tend to make a distinct noise when they are leaking. try that first before anything else ...dont take of the vac hose from the bov to the fpr else you will run lean on fuel , this hose increases the pressure of the fuel line ....

garath what happened to cant afford a supra because iam buying a house!!!

 

you have a boost leak in your intake manifold , you probley have change the fuel system because you are running a single. which means you have taken the intake manifold of in the past .turn the car on and spray wd40 on the intake side along where it attaches to the lower runner , and listen to the note of the car change .You can pinpoint where is is leaking this way , then try and tighten the nut in those locations. I would check your ic piping first , ususally doggy silicon hoses and clamps . Then look at the bov, i would say you have a boost leak on the pipe work or fmic ... bov tend to make a distinct noise when they are leaking. try that first before anything else ...dont take of the vac hose from the bov to the fpr else you will run lean on fuel , this hose increases the pressure of the fuel line ....

Hi Michel, i know i said that but then i found a bit of spare change behind the sofa so thought "what the hell".

The boost seems ok, it holds well at 1.1 Bar when on WOT it just doesnt seem to pull as well as it should, it hesitates a bit. I was thinking it was more my BOV or the fueling. But im not an expert by far thats why im after people's opinions before i book it in anywhere and start changing parts.

do you have a AFR GUAGE ?it does not sound like boost because you are boosting to 1.1 bar nor the bov , it sounds like doggy spark plugs . There is no way of checking to see if it is an injector because you dont have a AFR guage . what ecU is it ?

give me a ring 01642 563241 lets have a chat

ive just fitted a sard r2d2, and since fitting it i have low idle, stalling etc etc..i think i will put the old one back in and see what happens.