[Sparky68]

Originally Posted by idnan

I've got work then football afterwards on Friday but I'm going to be working on my car all day Sunday so you're more than welcome to pop down.

Cheers mate really appreciate the help.

[Sparky68]

Is this price per pair or each?
http://forgemotorsport.co.uk/content...oduct=FMDVBM35

[idnan]

That's for a pair

[Sparky68]

Originally Posted by idnan

That's for a pair

Thank **** for that

Are they the ones you have idnan?

[idnan]

Yep I've got the same ones in black

[doughboy]

Sparky,

Personally I doubt very much if its got anything to do with the DVs.

There's a lot of BS about DVs. Firstly remember DVs don't 'hold' boost. When the throttle is wide OPEN, the same boost pressure is present both sides of the DV (charge pipe boost underneath and manifold pressure on top). It is only as you close the throttle that a lower relative pressure occurs in the intake manifold and 'sucks' the DV open. The DV spring is only there to control the opening point, not 'hold' boost.

My forge DVs open at the correct 300mbar vacuum (same as factory units), this means they will 'blow' open with only 4.2psi of boost from the charge pipe. It is only the boost pressure fed back from the manifold to the top of the DV piston (via the small hose) that allows it to stay shut.

So even at 1,000,000psi of boost, as long as WOT the manifold is at running above 999,996psi then the DV will stay shut.

If it really was failing DV diaphragm you would more likely show OK boost up to standard, then it would drop sharply as they failed and leaked at higher boost.

Your's isn't doing that, it is low boost lagging way behind target from the outset. I would think vacuum system or actuators.

BTW you can't smoke test a vacuum system, smoke test are for positive pressures only (so the smoke comes out of leaks and you can see it).

If the bloke did indeed do a positive pressure test on the vacuum system, then a) it could damage things and b) its meaningless as push-on vacuum seals will leak like seives at positive pressure.

[Sparky68]

Originally Posted by doughboy

Sparky,

Personnally I doubt very much if its got anything to do with the DVs. Remember DVs don't 'hold' boost, when the throttle is OPEN, the same boost pressure is present both sides of the DV valve (charge pipe boost underneath and manifold pressure on top). It is only as you close the throttle that a lower relative pressure occurs in the intake manifold and 'sucks' the DV open.

If it really was failing DV diaphragm you would more likely show OK boost up to standard, then it would drop sharply as they failed and leaked at higher boost.

Your's isn't doing that, it is low boost lagging way behind target from the outset. I would think vacuum system or actuators.

BTW you can't smoke test a vacuum system, smoke test are for positive pressures only (so the smoke comes out of leaks and you can see it).

If the did indeed do a positive pressure test on the vacuum system, then a) it could damage things and b) its meaningless.

In that case i am really struggling to findout what is causing it, could the jb4 be faulty as it does not occur on standard map. Actuators or boost Solenoids have been suggested.

[doughboy]

Does it still do it if you turn the JB4 off, i.e map zero?

It could be a failed DV, but from the log it is failing from zero boost, so that means it would still be failing without the JB4.

Have you tried sending the logs to Terry at BMS?

[Sparky68]

Do not get any 30FF codes when on map 0 . Sent Terry the logs and he said "boost leak or faulty board"

[Sparky68]

Think there are more logs in this thread but, I am at work and the images are blocked.

http://www.e90post.com/forums/showth...ighlight=smoke

[doughboy]

Had a look, but your logs here show way off boost target from zero.

So is that was a leak, it would be leaking at standard pressures too, ie. jb4 off.

Does that make sense?

If the leak was at high boost then the car should perform normally up to that then it should drop or lag as the leak opened at higher pressure and the WGs need closing more to compensate.

[doughboy]

30FF is misleadingly called a 'boost leak' when it really just means 'target not reached'.

N54 has no air mass measurement (MAF sensor) so it doens't know there's a leak.

It only knows it is asking for 'xx' psi, but not getting it.

Could be a leak, or a MAP sensor fault, or WG fault, or actuator fault, or vaccum leak, or Solenoid fault.

Any part of the boost control system infact.

[Sparky68]

Guess i will just have to start changing bits and see if it cures it. Cant see any other way of finding out what it is.

[doughboy]

I would suggest the cheapest option would be a replacement JB4 unit, could be that.

BMS will do you a good price on just the controller i'm sure if you explain, you don't need the wires etc. And if it isn't that you can sell it.

The new super duper G5 board is only $150!!!

[idnan]

Which version of the JB4 have you got? I have a spare g4 doing nothing and a g5 fitted to my car. Both have worked perfectly on my car

[zltm089]

Don't change the DV yet.....

I'm gona put my money on the actuators...just because you're in a "similar" situation to me....

I don't get any issues when i'm on stock or the Drive map....only when i run higher boost...on aggressive maps...

[zltm089]

Originally Posted by doughboy

Sparky,

Personally I doubt very much if its got anything to do with the DVs.

There's a lot of BS about DVs. Firstly remember DVs don't 'hold' boost. When the throttle is wide OPEN, the same boost pressure is present both sides of the DV (charge pipe boost underneath and manifold pressure on top). It is only as you close the throttle that a lower relative pressure occurs in the intake manifold and 'sucks' the DV open. The DV spring is only there to control the opening point, not 'hold' boost.

My forge DVs open at the correct 300mbar vacuum (same as factory units), this means they will 'blow' open with only 4.2psi of boost from the charge pipe. It is only the boost pressure fed back from the manifold to the top of the DV piston (via the small hose) that allows it to stay shut.

So even at 1,000,000psi of boost, as long as WOT the manifold is at running above 999,996psi then the DV will stay shut.

If it really was failing DV diaphragm you would more likely show OK boost up to standard, then it would drop sharply as they failed and leaked at higher boost.

Your's isn't doing that, it is low boost lagging way behind target from the outset. I would think vacuum system or actuators.

BTW you can't smoke test a vacuum system, smoke test are for positive pressures only (so the smoke comes out of leaks and you can see it).

If the bloke did indeed do a positive pressure test on the vacuum system, then a) it could damage things and b) its meaningless as push-on vacuum seals will leak like seives at positive pressure.

Mike, lots of people on n54tech talk about the DVs not being able to cope with the higher boost....

when I spoke to Birds and Darren Woods, they did say that the DV could fail aswell....

but in my case, it was the actuators...

[zltm089]

Originally Posted by zltm089

Mike, lots of people on n54tech talk about the DVs not being able to cope with the higher boost....

when I spoke to Birds and Darren Woods, they did say that the DV could fail aswell....

but in my case, it was the actuators...

Just read your post again....

forget about what I said!!...yeah, in Sparky's case, the DV doesn't seem the cause of that boost leak code!...

[Sparky68]

Originally Posted by doughboy

I would suggest the cheapest option would be a replacement JB4 unit, could be that.

BMS will do you a good price on just the controller i'm sure if you explain, you don't need the wires etc. And if it isn't that you can sell it.

The new super duper G5 board is only $150!!!

Was looking at that might be a cheapish way of checking.

Originally Posted by idnan

Which version of the JB4 have you got? I have a spare g4 doing nothing and a g5 fitted to my car. Both have worked perfectly on my car

G4 i think mate.

[idnan]

Originally Posted by Sparky68

Was looking at that might be a cheapish way of checking.



G4 i think mate.

PM me your address and I'll post it to you tomorrow mate, I've got no use for it.

[Sparky68]

Originally Posted by idnan

PM me your address and I'll post it to you tomorrow mate, I've got no use for it.

You have to let me pay you something for it.

Will pm you my address, thanks mate your a star.

[idnan]

I was close to throwing it in the bin on Sunday, so don't worry about it. It isn't worth a penny without the wiring loom.