How to test stock Bosch BOV?

[GrantP]

I've tried to search but cant find the answer.

Is there an easy way to check if the stock BOV is working correctly as I think I may have a boost leak.

Car is a BAM S3.

Thanks

 

[<tuffty/>]

If you are getting a kind of 'choo choo choo' noise when you change gear at lowish rpm's then your divertor (its not a BOV ) is probably past its sell by date...

Have you checked everything else for leaks? favourite is under the inlet manifold...

What makes you think you have a leak?

<tuffty/>

 

[GrantP]

Don't think I really get a choo at low rpms.

It initially pulls well, but them seems to go a bit flat (haven't had the car long so don't know any different but doesnt feel 'right')

Also get quite alot of hissing when under full load at WOT.

 

[James TQ]

in reply to tuffty, i have a split in the breather pipe, couldn't find any on the web so ended up having to go to the stealer's and pay £28! but its made a major difference!

 

[<tuffty/>]

Don't think I really get a choo at low rpms.

It initially pulls well, but them seems to go a bit flat (haven't had the car long so don't know any different but doesnt feel 'right')

Also get quite alot of hissing when under full load at WOT.

Yep... sounds like its going into limp mode tbh... check under the inlet manifold.. the pipes look like this..

<tuffty/>

 

[GrantP]

Those pipes again, def need to check them!

Are they accessible with the manifold on, or do I need to take anything else off to get to them?

 

[<tuffty/>]

You should be able to check them in situe but sometimes easier to remove the trim and the metal bracket to get you r hand under... only trouble with that is you will most likely break the dipstick tube so worth buying a new one anyway as they are less than a fiver (iirc)

Use a torch...

<tuffty/>

 

[GrantP]

Well all pipes look good, can't find an splits etc.

Any way to test the Bosch valve when removed?

As I also have the intermittent fluffy idle issue could the MAF be the problem?

Again any way to test?

 

[pj123]

Push the diaphram up with a pen and then put your finger over vacuum pipe on top. Diaphram should stay put if its not nackered.

Idle may be down to the throttle body needing cleaning and resetting. If you dont have VCDS then disconnect the battery for 15 mins and it will realign itself.

If you have no vacuum leaks then flat spot could be dodgy MAF. If you dont have VCDs to check it then try disconnecting the MAF and driving. ECU reverts to standard figures for the MAF if not connected.

 

[GrantP]

I have not had time to try the above yet but I have noticed one thing.

If I apply the throttle gradually in 2nd or 3rd etc it seems to pull much better than if I just go straight to WOT.

Does this help indicate what may be the issue?

 

[Benjiman46]

Just throw it away and get a forge one mate... Bosch ones are just rubbish

Ben