Boost leak test

[Colesy]

Can’t feel any air blowing just loud air escaping checked all clips car drives normal even when you accelerate slowly the car picks up pretty quickly but when you plant it that’s when it becomes a kangaroo. I have a test leak kit but I’ve not done a test on the maf hose before only the one my kit fits but as said can’t remember how

Just unplugging and plugging back in the MAF used to fix this for me. That's not to say you don't have a leak but always worth trying the easy things first.

[newsh]

If you can hear loud air escaping then you have a big hole somewhere.

I’ve seen quite a few Diverter valves with holes in where the rest against something and wear through.

Leaks in the IC are hard to find because it’s hidden in the bumper.

Maf hose can be work through where it rests against the back of the headlight cowling.

Classic split point is under the throttle body hose next to the large clip.

The one way PCV valve hidden under the IM can stick open, this would mean pressure escaping into the PCV pipe and coming out near the Maf where you disconnected it.

If you haven’t replaced all the small bore vac lines and they are still the old cotton covered rubber, they will be rotten and leaking.

[newsh]

Double post

[bilko0795]

I have a walbro 450 fitted been on car 9 months was fine when installed

[bilko0795]

Have Roose fitted all round all small vac hoses replaced with silicone, bumper off the car, not checked the one way pcv valve sure it was done a few years back, but I’ve had a full gasket replacement done a year ago. The air sounds like it’s coming from around the turbo area

[Rikki Kitto]

Chasing boost leaksEvery S2 owners nightmare, good luck bud show pics when you find it I had a split hose but the split was under the jubilee clip so took a while to work it out

[larsaskogstad]

That reminded me that I will have to do a boost leak test before going out on the road
All brand new hoses but probably some leak some place anyway

[Rikki Kitto]

Always bro

[newsh]

I had the cold side bolts come loose once, that made for a very noisy leak!

[larsaskogstad]

If you can hear loud air escaping then you have a big hole somewhere.

I’ve seen quite a few Diverter valves with holes in where the rest against something and wear through.

Leaks in the IC are hard to find because it’s hidden in the bumper.

Maf hose can be work through where it rests against the back of the headlight cowling.

Classic split point is under the throttle body hose next to the large clip.

The one way PCV valve hidden under the IM can stick open, this would mean pressure escaping into the PCV pipe and coming out near the Maf where you disconnected it.

If you haven’t replaced all the small bore vac lines and they are still the old cotton covered rubber, they will be rotten and leaking.

Knew I shouldnt be skipping the vac line going from IM down to the diverter valve It looked okay condition but seems like I will have to try and change it, doesn't hurt changing anyway

[newsh]

Not the wastegate actuator hose? One from face of turbo to WGFV and one from there to WG.

Or the wastegate so knackered it’s leaking down the valve guide into the exhaust?

[larsaskogstad]

I dont know if I have boost leaks if you were replying to me
Ive changed everything else , was tidying up the vac lines in the rear the other day, but I have forgot about the one going long with the intercooler tube/pipe and down.

[newsh]

I dont know if I have boost leaks if you were replying to me
Ive changed everything else , was tidying up the vac lines in the rear the other day, but I have forgot about the one going long with the intercooler tube/pipe and down.

Still trying the help Bilko!

The DV line is definitely worth changing, although you can test it with a Mightyvac from the top end. This will check your DV diaphragm too.

[bilko0795]

Will take off all hoses and check for holes best way to make sure, I also have a new DV in my stash no rush car moth balled in garage getting some TLC

[newsh]

I use a cheap stethoscope with just a length of tube on it to listen for the leaks. I got it when I was trying to find a boost leak on the RS4 which turned out to be under the inlet manifold in the middle of the V, air temp sensor held in with one screw (yes they designed it like that !)

Anyway, you can listen with both ears which keeps outside noise at bay and feed the tube into those hard to reach nooks and crannies