Leaking Bov

[66yostagea]

Still at trying to solve my boost issue.

When you take a STOCK S1 BOV off, should there be no leak if you blow (no sex please) into it, which is SFA pressure. I have two BOVs here and both have a slight leak when shut. Is this normal??????

My prob is that sometimes when slowly accelerating it will boost to 1-3 psi then die inthe arse back to zero boost.If you pull over and try to rev it wants to cough and die, sometimes you can save it, but not always. Turn the key off and it starts Peter Perfect, and runs till next time it spits the dummy.

[wolverine]

The factory BOV is designed to leak slightly at idle.

If you have a pressure source on the top of the BOV identical to the other side it won't open.

Have you got an AFM issue? Poor plug connection, dry/cracked solder internally on the pins?

[66yostagea]

The factory BOV is designed to leak slightly at idle.

If you have a pressure source on the top of the BOV identical to the other side it won't open.

Have you got an AFM issue? Poor plug connection, dry/cracked solder internally on the pins?

I had a diagnostic, while driving. AFM,coilpaks, A/F mixture, spark, plugs all checked out OK. I feel i am looking for a leak somewhere.

Stick my head under the bonnet again.

[wolverine]

Can you wield a soldering iron, a stanley knife and some spanners?

[wolverine]

I should clarify the leak is mostly from that small hole on the face of the BOV to the side of the port.

[66yostagea]

I should clarify the leak is mostly from that small hole on the face of the BOV to the side of the port.

I figured that out. duh. my bad.

As Mike says it is an air leak and I am pretty sure its coming from where the AAC valve is. The problem now is I will have to take the plenum off to fix it.

To do this properly you need two slabs (at least) and two packs of bandaids. And probably a new plenum gasket.

Two slabs $70, Bandaids $10, gasket $98, total $178, plus extras say $200.

Might as well get the cam covers off and have them polished.

[wolverine]

You could try resoldering the AFM pins. It is about a 30minute job and it might explain why the issue is intermittent. Leaks tend to be constant in my experience.

[66yostagea]

You could try resoldering the AFM pins. It is about a 30minute job and it might explain why the issue is intermittent. Leaks tend to be constant in my experience.

That is what i cant understand. When the engine is idling you can hear a leak. Rev it a bit and it seems to go away.

Not 100% sure what you mean about resoldering the pins. I can solder tits on the Tin Man so if you give me a pic I can do it.

[QWK32]

do you think it could be the noise of the air being sucked through the AAC valve, i can see how it could be mistaken as an air leak, especially since yours in under the intake manifold, kind of tricky to get to and tell for sure.

to solder the air flow meter have a look through this tutorial -link to thread-

[DaveB]

What about getting hold of one of the ECUTalk displays; you can watch AAC and AFM voltage levels and see if anything goes haywire when the car cuts out? It also logs max values too. If it's AFM the AFM value may go either to ~0V or ~5V when the problem occurs.

[wolverine]

That is what i cant understand. When the engine is idling you can hear a leak. Rev it a bit and it seems to go away.

Not 100% sure what you mean about resoldering the pins. I can solder tits on the Tin Man so if you give me a pic I can do it.

There is noise from the PCV valve at idle that will disappear when you rev it. Does a FFP have a PCV still attached? I guess they delete it so perhaps not that?!!?

The afm is easy to solder....even I can do it and I am definitely not skilled in that department. The biggest issue is gouging out the silicon as it runs a bit deeper than you think. Once you pop it open the pins often look ok but hit them up anyway.

I have fixed 4 afm's with intermittent issues, stalling, misfires etc. It might be something else in your case but there is little downside in re-soldering.

[66yostagea]

There is noise from the PCV valve at idle that will disappear when you rev it. Does a FFP have a PCV still attached? I guess they delete it so perhaps not that?!!?

The afm is easy to solder....even I can do it and I am definitely not skilled in that department. The biggest issue is gouging out the silicon as it runs a bit deeper than you think. Once you pop it open the pins often look ok but hit them up anyway.

I have fixed 4 afm's with intermittent issues, stalling, misfires etc. It might be something else in your case but there is little downside in re-soldering.

Yes. The FFP has a dedicated line to the PCV. It could be that. I will have anot6her listen tomorrow.

[66yostagea]

Just getting back to the PCV. Its in the left bank cam cover. Is that positive pressure at idle and goes to vacuum at revs??

I need an expert to help me.

[zoomzoom]

The cam cover to manifold PCV has a 1 way check valve. When the manifold pressure is less than the cam cover, ie under vacuum, oily gases flow from the cam cover into the manifold. When the manifold pressure is greater than the cam cover, ie under boost, the check valve seals, and any blowby pressure is vented out of the other PCV breather pipe back into the turbo inlet. I think that explains what you want to know?

Edited November 24, 2010 by zoomzoom

[66yostagea]

Found a leak in the fuel PRV hose. Still hear the noise at the AAC but that could be normal as the hoses and fittings meander a lot.

We had road tested the AFM, A/f ratio and these were normal but the car did not play up while doing it.

After fixing the PRV leak I am sure the running is much smoother.

Test will come when I go on the cruise.

Edited November 26, 2010 by 66yostagea

[66yostagea]

Back to square one. Yesterday while L plate son driving, engine went into limp??? on the Gateway motorway. Car was running perfect for about 80ks, then poof. Got to the edge of road after cutting across lane. Turned off, started first kick, and ran sweet. On the way back, alone, it tried to limp about 6/7 times but by now I can handle it. But I considered it unsafe to take on the cruise. Bugger.

Fitted another AFM last night and will test over the next two days.

Found a leak where the PCV valve is in the L/H cam cover, but want to check the AFM first. Must do things one at a time otherwise I will not know what is the cause.

[66yostagea]

Put another ecu on last night. 80k run to coast and back this morning. No probs. Touch wood.

So "maybe" dry joints in the ecu. Hopefully.

[66yostagea]

OK another run to the coast and back, still OK. Must have been the AFM, but still going to fix the leak in the PCV. Every little helps.

[wolverine]

I am pretty sure it has been the AFM all along. Fingers crossed you are sorted now.