Boost leak

[Salg320]

Well, I just did my first boost leak test ever, and i found no leaks. Is that normal, or did i just do it wrong. From what i have read on this site, seems like there should have been one. O yea, i only pumped up to 8 psi, but i usually run at about 15 psi, but it was taking forever for it to pump up.

 

[_DeS_]

If it took forever to pump it is most likely leaking out somewhere. It usually shouldn't take that long to pump

 

[Salg320]

thats what I thought, but I didnt hear any air escaping or see any bubbles. where exactly should I be looking do you think?

 

[Gstclipse69]

What were you using to pump it up? You should test for at least how much boost you'll be running. I test for a little psi more than I run. Are you sure you didnt have any leaks. If you were using a compressor and it took forever then it seems like it would be leaking somewhere. It would be hard to hear if the compressor was running.

Listen around the throttle body and intercooler pipes.

 

[kenamond]

You have to use compressed air. Either an air compressor or a portable tank. Pressurize to 20psi and stop adding air. What does it do? Did you even get to 20psi? Major leaks won't let you even get to 20psi. Once you get those fixed, it'll get there but leak down quickly after you stop adding air. Track down the smaller leaks and fix them. When you're done, it should go to 20psi and leak down 1psi every few seconds.

Do it on a fully warmed-up motor or ring blowby will be horrible. Keep in mind that leaking valves, rings, and HG will look like boost leaks during the test, so if you have low compression, you might leak down more quickly.

PCV valve is something to check right off the bat. Same goes for loose couplers.

If you have problems finding leaks, do the BLT at the TB elbow (divide and conquer).

Find big leaks visually, medium leaks by ear (hissing), and small leaks with a spray bottle of super-soapy water.

There ya go.

 

[crimsondragon]

I thought that was pretty funny when you said "is that normal for a DSM to not have leaks?" Made my day. Here's a full breakdown of how to do the test.

1. Disable your mbc.

2. Turn your motor to 30* ATDC to avoid valve overlap.

3. Start your test at the TB elbow and focus on area behind the TB first.

4. Spray soapy water at TB gasket, BISS, TB shaft on both sides, IM gasket, injector insulators, brake booster, afpr and all vacuum lines/connections.

5. Open your oil cap and listen for leaks. (PCV, valve seals/guide, rings)

5. Listen to your tailpipe for leaks. (EGR, valve overlap, jumped timing, bent/unseated valves)

6. Once all leaks are fixed, move the tester back to the turbo inlet.

7. Spray down the compressor cover (known leak), BOV return/flange (DO NOT TAP YOUR BOV LINE FOR YOUR MBC!!!), IC end tank/fins and all connections. Re- test.

8. Note that you will leak air into the crankcase through the turbo seal but do not panic, this is normal during a static pressure test as long as there are no shaft play.

The desired test result from the begining of the LICP (bypassing turbo) is around 20psi (on boost gauge) with the compressor set at 30psi, while taking no less than 30 seconds to bleed down to 0.

As a reference, my last test on my 500 mile new engine, I was able to pressurize the system to 25psi, bled down to about 16psi (my 1G bov) in about 30seconds, then took about 3 mins to 6psi and just kinda lingered there for a while. It's not easy to do but the point is it's possible. My next goal is 30psi After motor break in and Dodge modding my BOV. A boost leak test is one of most pita but important regular maintenace task, the key is patience and endurance, have fun.

 

[Salg320]

I was using a pump that came out of my dads truck to pump up the tires. should that be good enough or no? But i guess i have a huge leak since it was taking so long. thanks for the input

 

[Salg320]

I thought that was pretty funny when you said "is that normal for a DSM to not have leaks?" Made my day. Here's a full breakdown of how to do the test.

1. Disable your mbc.

2. Turn your motor to 30* ATDC to avoid valve overlap.

3. Start your test at the TB elbow and focus on area behind the TB first.

4. Spray soapy water at TB gasket, BISS, TB shaft on both sides, IM gasket, injector insulators, brake booster, afpr and all vacuum lines/connections.

5. Open your oil cap and listen for leaks. (PCV, valve seals/guide, rings)

5. Listen to your tailpipe for leaks. (EGR, valve overlap, jumped timing, bent/unseated valves)

6. Once all leaks are fixed, move the tester back to the turbo inlet.

7. Spray down the compressor cover (known leak), BOV return/flange (DO NOT TAP YOUR BOV LINE FOR YOUR MBC!!!), IC end tank/fins and all connections. Re- test.

8. Note that you will leak air into the crankcase through the turbo seal but do not panic, this is normal during a static pressure test as long as there are no shaft play.

The desired test result from the begining of the LICP (bypassing turbo) is around 20psi (on boost gauge) with the compressor set at 30psi, while taking no less than 30 seconds to bleed down to 0.

As a reference, my last test on my 500 mile new engine, I was able to pressurize the system to 25psi, bled down to about 16psi (my 1G bov) in about 30seconds, then took about 3 mins to 6psi and just kinda lingered there for a while. It's not easy to do but the point is it's possible. My next goal is 30psi After motor break in and Dodge modding my BOV. A boost leak test is one of most pita but important regular maintenace task, the key is patience and endurance, have fun.

Thanks, thats great. one question though, what do u mean turn my motor to 30? I also dont have a MBC yet.

 

[Gstclipse69]

30* ATDC [after top dead center] If you take your timing belt cover off , tdc [top dead center] is where both the dowel pins on the cam gears are pointed directly up, and the marks on the cam gears line up with themselves in the center. 30* atdc will be when the valves are closed. You can rotate your motor to 30* by turning the crankshaft, which is right behind the drivers steering wheel with, I believe a 1/2" square extension.

 

[DougR]

Tip for ya. since noone said anything about it. Once you find and Fix ALL Leaks.
Guess you could do this before testing. just to reduce the amount of potential leaks.

Use Small Zip Ties on EVERY Vacume Line end under the hood that doesnt already have a Screw Type Clamp on it!!! Pull them Tight! but dont break anything!
ofcourse use Black zip ties or you will quickly hate yourself. as there are ALOT of places to Zip tie lines!!
Do them ALL! or run the risk of popping one off while driving after fixing your boost leaks and actually building a good PSI.
There are some nasty hard to reach lines under your intake manifold. all around the EGR. beshure to take the time and effort to get those also.


Doug,

 

[kenamond]

I've never had a problem with valve overlap. But if you do turn the crank manually, it must be clockwise or the timing belt can jump a tooth. Also, once you fix all of the leaks, future boost leak tests are simple...they are just checks that nothing is leaking. Since I fixed all of mine, I've gone 10k miles without a leak.

 

[burbage2001]

Are you using a electric air compressor that you plug into your lighter. I tried using one of them and I could not hear any leaks or build up good pressure, so I got a portable tank. I ended up finding several leaks that I was able to fix. I also read several article where other people were having problems with those small compressors.

 

[kenamond]

Are you using a electric air compressor that you plug into your lighter. I tried using one of them and I could not hear any leaks or build up good pressure, so I got a portable tank. I ended up finding several leaks that I was able to fix. I also read several article where other people were having problems with those small compressors.

Agreed. Get yourself an 11 gallon portable air tank. They're pretty cheap at WalMart etc. They're very handy to have in the garage for topping off tire pressure, too. I'd rather have an air compressor so that I could use air tools, but the air tank is far more affordable, they take up far less space, and you can carry them around.

I've also heard plenty of failed attempts using bike pumps and cigarett lighter doo-dads. If you have a lot of leaks, you might have to refill the air tank once or twice. I know I did.

 

[1gDSM4g63]

If it took forever to pump it is most likely leaking out somewhere. It usually shouldn't take that long to pump

What the average time?

 

[Salg320]

Agreed. Get yourself an 11 gallon portable air tank. They're pretty cheap at WalMart etc. They're very handy to have in the garage for topping off tire pressure, too. I'd rather have an air compressor so that I could use air tools, but the air tank is far more affordable, they take up far less space, and you can carry them around.

I've also heard plenty of failed attempts using bike pumps and cigarett lighter doo-dads. If you have a lot of leaks, you might have to refill the air tank once or twice. I know I did.

Yea, it plugs into the cigarette lighter. Guess I'll be heading to walmart tomorrow morning . Hopefully I can have them all patched up for tomorrows meet at the san antonio speedway

 

[kenamond]

Yea, it plugs into the cigarette lighter. Guess I'll be heading to walmart tomorrow morning . Hopefully I can have them all patched up for tomorrows meet at the san antonio speedway

Maybe, but some of the leaks might require you to order parts...such as injector insulators. But you never know. If you have a Mitsu dealership nearby, they might have some of the parts in stock, but it'll cost more than getting them online. My closest Mitsu dealership always has to order *everything* I needed (PCV valve, injector o-rings, etc.), but there aren't a whole lot of turbo DSMs around here.