Boost leak testing

[reNgrOets19]

Alright guys this is probaly a stupid question but on a stock 1g awd turbo laser when u are doing a boost leak test what do u do with the dump tube on the stock bov do u plug the end of it with something or just take it off and leave the bov open?.....thanks guys

 

[wallyman]

Your BOV should be closed under pressure.

 

[yokotabrat]

How are you performing the test? Usually when I do a boost leak test, I remove the MAS pipe and hook my tester directly up to the inlet of the turbo. From there you can just leave the bov dump tube connected to the mas pipe. Hope this helps.

 

[RedGSX21]

just leave the tube open, it shouldnt leak out of there

 

[kenamond]

Since you're pressurizing the intake, and since the diaphragm in the BOV is actuated by vaccum above it (via the vac line between the nipple and the IM), adding pressure during your boost leak test should actually hold the BOV closed (you pressurize the IM which pressurizes the top of the BOV diaphragm which holds the valve in the BOV closed). You can pull off the dump tube, though, spray soapy water in there, and check for bubbles, but then you have soapy water on the inside of your intake system which might not be very good (don't know). Alternatively, you could pull the dump tube off and just put your ear to the BOV exit and listen to see if it is leaking boost.

Another hint. You may run into the first obvious leak and go to fix it, but you should probably try to find every leak you can in the first shot. Otherwise, you might, for example, fix a leaky TB gasket first and then have to pull that part off again to fix another leak that you find in your next round of tests. Get a spray bottle and spray everything on the TB, IM, including the injector insulators (between injector and head), and pull your valve cover breather line off of your intake pipe. Pressurize and listen to the valve cover breather hose. That could mean worn rings or valve seals, but it might just be a bad PCV valve. If it's the PCV, pull it from the valve cover and hold your finger over the end and repeat the test so that you can hold enough pressure to identify other leaks.

I'd identify all TB/IM/injector leaks before you try to fix any of them. The IC piping, depending on what you're running with can **usually** be tested/disassembled separately, but the big exception is if your TB elbow is replaced with a hard UICP, as this means to pull it, you have to pull the TB off which might introduce a new leak or reintroduce a leak you already fixed.

 

[reNgrOets19]

Alright thanks alot guys...

 

[reNgrOets19]

now should the key be on or the car completly off?

 

[kenamond]

now should the key be on or the car completly off?

Off. I can't think of anything that needs power during the boost leak test except maybe an EBC, but you may want to remove that from the equation by capping the boost source line anyway.

 

[91Bomb]

I know this is an old thread but need to ask a question. One guy said to hook the tester up to the turbo inlet which is how I plan on doing it and if I'm running 15 lbs boost how much should I pressurize the system for above that and how long should the system hold say 18-20 lbs before dropping off? Also I guess I'd need someone inside my car looking at my boost gauge to tell me what's what, right?

 

[justinschmiidt]

I know this is an old thread but need to ask a question. One guy said to hook the tester up to the turbo inlet which is how I plan on doing it and if I'm running 15 lbs boost how much should I pressurize the system for above that and how long should the system hold say 18-20 lbs before dropping off? Also I guess I'd need someone inside my car looking at my boost gauge to tell me what's what, right?

Unless you have dsmlink and you're logging a map sensor, or you run your boost gauge into your engine compartment so you can watch it, yes you'll need somebody watching the gauge.

If you're running for 15psi, you shouldn't need to go very far above that. I would maybe shoot for 20psi, and it should bleed down SLOWLY over the next minute.

 

[tsd123]

Make sure you have the engine on tdc.

 

[91Bomb]

Make sure you have the engine on tdc.

How do you do that?

 

[nitroazz]

Considering that there are 4 different pistons running inside the engine, 2 at tdc and 2 at bdc, just in different cycles of suck, squeeze bang and blow it could be difficult.

Normally you will put your number one cylinder at tdc and that will make the engine be at "tdc"
You can place a driver on your crankshaft pulley and rotate it until the timing marks line up properly, at least there should be timing marks...

hope that helps.

 

[91Bomb]

Ok didn't know you were supposed to do that for boost leak tests so just get that white mark on t-belt or pulley to line up TDC?

 

[Bluefire16]

Nitorazz..... i have never heard of this? I no a number of members and none of us do that for a BLT.

And the vfaq says nothing of the sort for a blt........IC Pipe Tester

 

[68442]

You do not want your engine at tdc, you want it 30 degrees off.

 

[justinschmiidt]

Maybe they're talking about leak down tests? I've never had any issue with the BLT done without locating TDC

 

[68442]

http://www.dsmtuners.com/forums/newbie-forum/307590-does-motor-need-tdc-do-boost-leak-test.html