I've been trying to isolate a chronic boost leak and just can't for the love of god find out what the issue is. Currently I've got the front end of my Z off (and as a result I've now missed my MOT) checking as much of the pipework as possible, everything is tight, all the hoses are fitted correctly and in good condition yet the boost needle sits on 0.

 

I have an additional boost leak somewhere else which I have had for a while that I can't identify either noticed by when off boost, vacuum doesn't drop totally to -14 (sits around -10) Despite rigging it up to a boost leak detector, absolutely NOTHING and it's driving me up the ****ing wall.

 

What else can I possibly do!?

 

Symptoms

 

* Boost needle sits at 0 all the time.

* No hissing - feels like it develops boost still, just not as responsive.

* Boost leak detector indicated atmospheric pressure (system wouldn't pressurise).

* No visible or audible leaks, hoses all fitted correctly and tightened down.

if it won't boost at all, one of the turbo's could have failed

 

assuming when driving it falls flat on it's face when going into boost - that's a leak.

Have you checked the Turbos ?

 

And the connection to them ?

Have you checked the Turbos ?

 

And the connection to them ?

 

You'd hear something quite audible....which I don't.

 

if it won't boost at all, one of the turbo's could have failed

 

assuming when driving it falls flat on it's face when going into boost - that's a leak.

 

No, it's boosting all ok. Just not as responsive and feels like it's running out of puff.

Edited May 1, 201510 yr by Funkysi

you need to put another gauge on, just to verify. if the needle says zero, either the MAP sensor isn't working for the gauge (driver side next to small fuse box) or you're not getting boost ,,,

It was a known working gauge....

doesn't good for you then. Original turbos? To get zero boost, that's a huge leak, ie pipe blown off. You'd still get boost eventually with a small vac hose leaking, it'll just spool slower and not hit the same peak boost number.

 

If a single turbo has gone, you won't see positive boost

ps you should still be able to pressurise the system with a boost leak detector, what are you using?

FAIL! I spotted a tiny hose.....the hose for the gauge...yes...that had blown off. But I couldn't see it! I went straight for the jugular and thought I'd blown a main hose. I did have a few that were loose, they've now been tightened also.

 

The other issue is still there however, when in vacuum, the gauge doesn't shoot down to -14, it sits at -10 and I can't pressurise the system I forget the make of the boost leak gauge. I'll ask Jim, it was one of Josh Lake's. I still generate +14lbs

what are you pressurising it with? foot pump etc sounds like you may have a few more leaks to find

Compressor. Had it on there for a while and it won't pressurise the system. No leaks could be detected, audibly or visibly. I guess the only way to really check it would be to fill the system with UV gas and look at it under ultra violet light....not sure where I could get that done!

 

I assume since there's no hissing or anything that either the leak is so big (can't imagine that as I am getting full boost) or it's before the inlet.

I'm sure you know this si but it won't boost in neutral. You need load to spool them. Smoke pellets are winner, as is soapy water.

FFS!! I know! lol Muppet! ;) Should still sit vacuum though! Anyway, it's sorted to an extent.

Yeah you will get a vac reading nice healthy one. -10 doesn't sound too bad, I would expect that at idle maybe a touch more on over run.

It doesn't really go much more in over run...if the boost check is to be believed, it should go lower if the system didn't have, what I suspect is a pre-inlet leak.

Smoke it Si. Yourll probley find leaks even were you thought there wasnt.

Smoke it, scope it, don't just poke and hope it :yes:

I'm sure you know this si but it won't boost in neutral. You need load to spool them. Smoke pellets are winner, as is soapy water.

 

Mine boosts in neutral :whistling:

I had a split in the silicone coupler on one of the turbo which was really hard to track down. I think smoke matches might help mate?

Mine boosts in neutral :whistling:

 

Not the norm though is it...mine boosts about 2 psi if I give it stick at idle.

Not the norm though is it...mine boosts about 2 psi if I give it stick at idle.

 

Mild anti-lag is perfectly normal. 14psi at standstill just to get off the line. Not saying the Zed is a tanker, but it's no Westfield :laugh:

Not the norm though is it...mine boosts about 2 psi if I give it stick at idle.

 

But yours isn't a TT? ........:whistling:

But yours isn't a TT? ........:whistling:

 

That's the problem it was when it wasn't supposed to be or the other way round depending on how you look at it. A VG30DE+(TT). It's very much a VG30DETT now though lol.

Mild anti-lag is perfectly normal. 14psi at standstill just to get off the line. Not saying the Zed is a tanker, but it's no Westfield :laugh:

 

14psi at idle! I can't wait to get through this stage to get to the Noel make it faster stage.

14psi at idle! I can't wait to get through this stage to get to the Noel make it faster stage.

 

The joys of Nistune. It's like a full-on Group B whale :laugh:

 

It's not at idle though, but it is whilst stationary!

Corse not idle, duhhh. But very impressive. At what point would you recommend to go that bit further than a chip and use nistune? It's obviously more expensive.