Dumb question...but when performing boost leak check....

[adam355]

Whatever psi you pump it up to it should stay there right? I couldnt physically hear any leaks but the pressure was dropping slowly on the gauge so that means I still have a leak Im missing right?

 

[xcelr8n]

how high did it get on youre gauge??
and how fast as it creeping down to 0, it should slowly creep

 

[adam355]

how high did it get on youre gauge??
and how fast as it creeping down to 0, it should slowly creep

I pumped it up to 15 psi and it prolly took less then a minute to drop back to 0. Can't remember for sure though. Also my vacuum at idle is only 15 so....


edit: Mod's, just realized I accidently posted in the prob. diag. forum, if you wanna move it to newbies thats cool.

 

[R3dR]

if you want to be 100% sure your system is sealed to the throttle body then take the hose off the throttle body and close it off for the test.

Just get a pvc end cap that fits inside your upper IC right b4 the throttly body and clamp it in.

Then do the test as normal, yo can have 100% sealed to the throttle body.

 

[adam355]

Yeah the only thing is I think one of my leaks may be in the throttle body, thanks for the input though. I will try that as well to make sure there aren't any before tb leaks.

 

[44pirate]

After many boost leak tests, I find it benificial to test it when the car hasn't run yet for the day. Every thing is at its smallest meaning it has expanded do to heat. Rubber silicone expands more then steel. Pressure it up at least 5 psi more then what boost you like to run.

 

[AL92]

Ok last time I tried to boost leak test I kept blowing off the tester at about 15psi no matter how much I tighten it.Also should I test with throttle open and throttle closed to check for things like leaks to the tb and then for leaks after like at injectors or intake manifold.And how am I supposed to test it if the test blows off at 15psi.??Its the standard one made from fernco fitting.

 

[PaleDSM]

Testing with the throttle open or closed won't change your readings. The throttle body isn't sealed completely when it is closed.

It is hard to say if your pressure dropping is normal but it doesn't sound too far off the mark to me.

What kind of turbo are you pressurizing through. I ask because some turbos use smooth inlet bells which are a bi*** to get a tester coupler to stay on and others have a lip which makes it easier.

 

[AL92]

I have a 50 trim agp rs49 turbo.It is very smooth in fact my intake pipe can come off also if you don't really tighen it down.I tighten heck ouf out of my tester .Last time I checked though my lower intercooler hose was pinched bad so maybe that was messing the test up.Have to check again now that fixed that hose.