I have just purchased one for my MY99. Since fitting i've noticed that when stopping the car i.e traffic lights, the engine dips below normal idle speed, then returns. Strange. I have no idea why it's doing this!

Any ideas would be appreciated.

Gav

 

I thought that idling problems were in some cases a common problem with a VTA d/v.

Best advice is to do a search on VTA d/v's and see what other problems if any other owners have had.

 

This can be sorted very easily..

With the car warm, and idling:

Crack the 10mm lock nut on top of the blow off valve, then (with the correct size allen key for the allen bolt adjuster) turn the adjuster anticlockwise until you see the plunger inside the BOV body open (looking down the trumpet of the BOV), then turn the adjuster clockwise until it shuts, once it's at the point where it is shut at idle, just give it another half a turn or so, give it a rev and watch the action of the plunger, then lock the allen bolt off with the 10mm nut.

Basically the BOV needs to be shut at idle for it to give no bad idling problems. If it still dips the revs when coming to a stop, give it some more adjustment (ie clockwise), until it idles fine, the more clockwise turn you put on the adjuster, the more preload you put on the spring in the BOV. Basically at the moment, when you are dipping the clutch the preload on the spring is not strong enough, therefore the plunger in the BOV is not shutting fast enough and you are getting the dip of revs (where the BOV is open as you come to idle) just before the plunger shuts.

 

James you are a star mate! I'll look at it tomorrow when it's light. I thought i may be damaging stuff by allowing the car to do this. By adjusting the locking nut will i alter the sound of the dump valve?? It sounds really nice at the moment and i dont really want to end up with a piddly pss instead of a pppppppssssssshhhhhhh!

Thanks again James, really appreciate it.

Gavin

 

Should be fine mate, it won't need a lot more adjustment on it. Basically it's just not quite shutting fast enough, so a bit more preload on it and it should be fine.