Boost Leak Detectors?

[mantav8]

I know i'm gonna regret asking this,but how exactly do they work? :confused:

So you bung it in where the afm goes and pressurise with about 3-5 psi-right?

The air goes in the induction pipes,to the tubs,then the intercoolers and in the tb's.This is where I get fuzzy :rolleyes: What stops the air going past the butterflys,into the plenum,cylinders etc-and straight out an open exhaust valve?

I await the onslaught!! :x:

[mantav8]

Still waiting! :o

[Guest andyduff]

Cos the butterflys are shut? :x: ;) And be ****in patient in future :D

[mantav8]

Cos the butterflys are shut? :x: ;) And be ****in patient in future :D

Are they shut??how do the car tick over then??-patience is not one of my virtues!! :tongue:

[Gio]

Are they shut??how do the car tick over then??-patience is not one of my virtues!! :tongue:

 

As I understand it, you pressurise the system while the engine is off. Otherwise how could you hear the small hiss of escaping air which tells you where the leak is?

[mantav8]

As I understand it, you pressurise the system while the engine is off. Otherwise how could you hear the small hiss of escaping air which tells you where the leak is?

 

 

yep,got that,but when the engine is off,the b/flys are still in an ''idle'' position

or am i wrong and they are completely closed and the iav takes care of tickover?[tell i'm used to deisels :confused: ]

[Guest andyduff]

Yep, throttle flaps are fully shut. The ecu opens and closes the idle valve very rapidly to control the amount of idle air bypassing the TBs

[Mark]

Mantav8,

 

I take it you've bought one of these boost leak detectors?

 

Have you used it now? Found any leaks?

[mantav8]

Mantav8,

 

I take it you've bought one of these boost leak detectors?

 

Have you used it now? Found any leaks?

 

No not got one yet,m8,gonna make one up if I know for definate they work!

[John Dixon]

Dunno where you are in the midlands, but I've got one (Kidderminster) if you want to pop over sometime.

You do get some air passing through the throttles and the bleed on the idle valve, but if you use a small compressor you can get the pressure up enough to hear it bleed down. Or block the exhausts.

[mantav8]

Dunno where you are in the midlands, but I've got one (Kidderminster) if you want to pop over sometime.

You do get some air passing through the throttles and the bleed on the idle valve, but if you use a small compressor you can get the pressure up enough to hear it bleed down. Or block the exhausts.

 

Thanks a lot for the offer bud,but you just made it all clear!!-you DO get some air bypassing the b/fly's-thats the bit I couldn't get my head around!!

Again ta very much!! :duffer:

[Guest Dave Marley]

Dunno where you are in the midlands, but I've got one (Kidderminster) if you want to pop over sometime.

You do get some air passing through the throttles and the bleed on the idle valve, but if you use a small compressor you can get the pressure up enough to hear it bleed down. Or block the exhausts.

I got one of these today and I don't seem to be able to get much pressure into the system. The only air I can hear escaping is around the back of the engine, around the area of the idle valve. Are you saying that's normal?

 

Thanks

[vijay]

Hi Dave,

 

Have a read here, it sounds like it could be your EGR too.

 

http://home.swipnet.se/e-solutions/Vacuumleak.html

 

Vijay

[Guest andyduff]

Thanks a lot for the offer bud,but you just made it all clear!!-you DO get some air bypassing the b/fly's-thats the bit I couldn't get my head around!!

Again ta very much!! :duffer:

 

You should have NO air passing the TBs!!! If you do the ecu cannot efficiently control the idle. You will get some air bleeding into the carbon cannister though from the passenger TB as the pickup is just before the flap in the TB....

[Guest Dave Marley]

Well I've found my air leak, or at least the first air leak...

 

It's leaking out around the seal between the upper and lower parts of the IAA valve (marked in blue on the picture).

 

Is there any reason why it would leak around there? Is there a replacement seal I can buy, or would I have to replace the whole thing?

 

Thanks

[vijay]

Hello Dave,

 

Have a look here - http://home.swipnet.se/e-solutions/IdleTech.html could it be leaking from the gasket between the IAA unit and the plenum? (this gasket - http://www.courtesyparts.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=CP&Product_Code=23781-Z3200 ) if it is the p/n is 23785N

 

Congratulations on your first find ;)

 

Vijay

[Guest Dave Marley]

Hello Dave,

 

Have a look here - http://home.swipnet.se/e-solutions/IdleTech.html could it be leaking from the gasket between the IAA unit and the plenum?

Sadly not. It certainly seems to be the seal between the 2 parts of the IAA unit. :(

 

Congratulations on your first find ;)

Thanks, although I'll be happier when I find out that it was my *only* find! ;)

[vijay]

OK, I'm not finished yet ;) how's about trying this stuff - http://www.frost.co.uk/item_Detail.asp?productID=8307

 

Vijay

[Guest Dave Marley]

Excellent. I planned to take it all apart to clean it up anyway as I've been having high idle problems. I suspect a leak like that won't help!

 

I'll remove it all and see if I can seal it properly.

 

Thanks vijay

[Guest andyduff]

Dave, take the rubber hoses off the offending t-piece and try twisting and pulling it out. Apply some araldite to the outside and re-insert, job done ;)

[Guest Dave Marley]

Will araldite make a seal that air won't get past though? Certainly worth a try though! Thanks

[Guest andyduff]

As long as you give it a good smearing on the outside and the fit is tight then yes it will. The reason I suggested araldite is due to its gap filling properties ;)

[Guest Dave Marley]

I couldn't get the t-piece out in the end. :(

 

I bought one from AndyZ and it seems to be a slightly different design. On mine (from a 1991 import), the t-piece seems to just slot (or possibly screw) into the main unit and is held in place by a small metal notch that fits into a hole in the main unit.

 

On the version I got from Andy, the t-piece has a flange around where it meets the main unit and a screw to hold it in place. Hopefully that will stop any leaks similar to the one I had! :hyper: