Boost leak test

krautastic · **Joined:** Sat Jun 03, 2017 9:52 pm **Posts:** 33

I've searched plenty, but can't find anyone actually talking about doing a boost leak test. Others have asked, but none have reported actually doing it (except testing the intercooler). Has anyone done one on the CRD? Anything to look out for when pressurizing the system? Planning to either pressurize at the inlet to the turbo/intercooler hose or before the turbo. Will take out the oil cap as well, just need to know if there's any danger to the oil system or if popping the oil cap will cover it.

Reason for boost leak test: pulled the FCV/intake elbow to cap the EGR cooler lines in an attempt to figure out a small coolant loss. I recall seeing closer to 20psi on torque, now I am only getting to 16psi that tapers off pretty fast. GDE eco tune is supposed to hold 20psi over ambient up to 3800rpm, and that is not what I'm getting. Also, getting what can only be described as air-cooled VW air whistle when boosting. This is in addition to the normal turbo sound.

mass-hole · **Posted:** Sun Jul 09, 2017 9:11 pm

krautastic wrote:

I've searched plenty, but can't find anyone actually talking about doing a boost leak test. Others have asked, but none have reported actually doing it (except testing the intercooler). Has anyone done one on the CRD? Anything to look out for when pressurizing the system? Planning to either pressurize at the inlet to the turbo/intercooler hose or before the turbo. Will take out the oil cap as well, just need to know if there's any danger to the oil system or if popping the oil cap will cover it.

Reason for boost leak test: pulled the FCV/intake elbow to cap the EGR cooler lines in an attempt to figure out a small coolant loss. I recall seeing closer to 20psi on torque, now I am only getting to 16psi that tapers off pretty fast. GDE eco tune is supposed to hold 20psi over ambient up to 3800rpm, and that is not what I'm getting. Also, getting what can only be described as air-cooled VW air whistle when boosting. This is in addition to the normal turbo sound.

Where are you located elevation wise? Could be the boost limiter if you are at higher elevations.

I also disagree on the 20 psi to 3800 rpm. The boost will spike above 20 briefly but I don't think it holds it there.

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krautastic · **Joined:** Sat Jun 03, 2017 9:52 pm **Posts:** 33

I'm in colorado, so at altitude. Here's where I got the info:

Quote:

With the OEM calibration, you'll find that peak boost is a pressure ratio of 2.335 bar respective to atmosphere at 2200rpm. On a boost gauge, you would see: (2.335bar - 1 bar (atm) ) * 14.7 psi/bar = 19.6245psi. In a transient maneuver you might see it spike up higher quickly, but in steady state conditions 20psi would be the max. However, at RPM climbs above 2200rpm, the boost setpoint falls off quickly, and by 3800rpm you're down to a 2.24 pressure ratio / 18.228psi.

With the GDE Eco-performance tune and the turbocharger at maximum speed limits, we have a boost setpoint that holds a 2.4 pressure ratio / 20 psi all the way from 1800rpm to 3800rpm. However, the real change is in the normal driving range where you'll see an increase, in some areas, of 5-6psi or higher.

There was never any changes to the boost setpoint that would've had customers seeing 26psi on a boost gauge - if they were, it would've been in a transient maneuver where the closed-loop boost governing wasn't reacting fast enough and allowed for an overshoot of the boost setpoint (most likely in first gear during a WOT).

http://www.greendieselengineering.com/j ... ist/7.page

flash7210 · **Posted:** Mon Jul 10, 2017 12:21 pm

Most boost leaks you can hear. (like a "whoosh" or a "whistle")
A serious boost leak will cause a P0299 underboost code.

What boost level does torquepro display with the key-on engine-off?
Typically, when you are at a high altitude, it will be a negative number.

I'd go back and make sure that your intake elbow and EGR connections are bolted down tight.

Maybe you forgot to put a gasket in?

If your EGR is still connected, maybe its stuck open and allowing boost to escape out the exhaust.

mass-hole · **Posted:** Mon Jul 10, 2017 2:12 pm

krautastic wrote:

I'm in colorado, so at altitude. Here's where I got the info:

Quote:

With the OEM calibration, you'll find that peak boost is a pressure ratio of 2.335 bar respective to atmosphere at 2200rpm. On a boost gauge, you would see: (2.335bar - 1 bar (atm) ) * 14.7 psi/bar = 19.6245psi. In a transient maneuver you might see it spike up higher quickly, but in steady state conditions 20psi would be the max. However, at RPM climbs above 2200rpm, the boost setpoint falls off quickly, and by 3800rpm you're down to a 2.24 pressure ratio / 18.228psi.

With the GDE Eco-performance tune and the turbocharger at maximum speed limits, we have a boost setpoint that holds a 2.4 pressure ratio / 20 psi all the way from 1800rpm to 3800rpm. However, the real change is in the normal driving range where you'll see an increase, in some areas, of 5-6psi or higher.

There was never any changes to the boost setpoint that would've had customers seeing 26psi on a boost gauge - if they were, it would've been in a transient maneuver where the closed-loop boost governing wasn't reacting fast enough and allowed for an overshoot of the boost setpoint (most likely in first gear during a WOT).

http://www.greendieselengineering.com/j ... ist/7.page

Well I think that is your answer. At 6500 feet the stock tune cuts 170 mbar of pressure. So you go from 2335 mbar to 2165. That right there is 16.7 psi of boost.

If you can monitor in KPA absolute pressure instead of boost that is more similar to how the jeep is programmed. The Ecu thinks in absolute pressure, not boost.

Also, just to be safe, compare you manifold absolute pressure to you androids internal barometric pressure. They should be the same with the key on but engine off. My MAP sensor was reading 880 mbar when my phone was at 800. I swapped MAPs and it reads 800 now.

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krautastic · **Joined:** Sat Jun 03, 2017 9:52 pm **Posts:** 33

flash7210 wrote:

Most boost leaks you can hear. (like a "whoosh" or a "whistle")
A serious boost leak will cause a P0299 underboost code.

What boost level does torquepro display with the key-on engine-off?
Typically, when you are at a high altitude, it will be a negative number.

I'd go back and make sure that your intake elbow and EGR connections are bolted down tight.

Maybe you forgot to put a gasket in?

If your EGR is still connected, maybe its stuck open and allowing boost to escape out the exhaust.

That does remind me. The PO had used the copper/red high temp RTV on the EGR line where the clamp goes. I did not. With that style of joint, I don't know why you'd need additional RTV. The other gaskets were all new. I looked over the intercooler to intake pipe for any holes/tears and found none. The turbo to intercooler has a sheath on it with heat shrink at either end. I did not remove the sheath to inspect, but may do that prior to a leak test.

Ah, the other reason for interest is if I floor it, I am definitely putting down a smoke screen, which is supposedly evident of a rich condition/not enough air. Maybe it is a normal amount of smoke for one of these. But, I also can not get above 25mpg even with high way driving, when so many other eco tune owners claim 30+.

WWDiesel · **Posted:** Mon Jul 10, 2017 4:48 pm

Could be your EGR valve leaking boost back into the exhaust manifold if your EGR system is still connected? :roll:

Simple solution to rule out, blank it off!

viewtopic.php?f=5&t=76576

krautastic · **Joined:** Sat Jun 03, 2017 9:52 pm **Posts:** 33

I definitely thought about blocking off the EGR, but decided not to after reading that GDE uses the EGR valve as a type of turbo dump valve. Then I came to the realization that diesel's don't really need a blow off valve. I may go back to do that.

f5hunter · **Joined:** Fri Jan 09, 2015 6:04 pm **Posts:** 45

I too suspected a minor boost leak based on torque pro readings...but as of yet have not found any leaks. My torque pro app shows a brief peak boost of around 21 and holds steady around 18-19 psi during a full throttle run. This is with a GDE ECO FT tune at 1000 feet MSL.
My EGR is removed and blocked off. New MAP sensor (the cheap Bosch one). Turbo actuator vacuum and rod are all operating correctly. Smoke on hard acceleration is minimal. Stock tires and ride height and I get about 27-28 mpg on highway at ~70mph.

mass-hole · **Posted:** Tue Jul 11, 2017 1:07 pm

f5hunter wrote:

I too suspected a minor boost leak based on torque pro readings...but as of yet have not found any leaks. My torque pro app shows a brief peak boost of around 21 and holds steady around 18-19 psi during a full throttle run. This is with a GDE ECO FT tune at 1000 feet MSL.
My EGR is removed and blocked off. New MAP sensor (the cheap Bosch one). Turbo actuator vacuum and rod are all operating correctly. Smoke on hard acceleration is minimal. Stock tires and ride height and I get about 27-28 mpg on highway at ~70mph.

That sounds exactly right. Why is everyone convinced they have a boost leak?

mass-hole · **Posted:** Tue Jul 11, 2017 1:07 pm

krautastic wrote:

I definitely thought about blocking off the EGR, but decided not to after reading that GDE uses the EGR valve as a type of turbo dump valve. Then I came to the realization that diesel's don't really need a blow off valve. I may go back to do that.

Check your PM's!

WWDiesel · **Posted:** Tue Jul 11, 2017 1:45 pm

krautastic wrote:

I definitely thought about blocking off the EGR, but decided not to after reading that GDE uses the EGR valve as a type of turbo dump valve. Then I came to the realization that diesel's don't really need a blow off valve. I may go back to do that.

NO electronic tune can prevent a mechanical malfunction of the EGR valve sticking party open and allowing boost to leak back through it into the exhaust manifold.
Only sure way to guarantee no boost lost through an EGR valve is to either blank it off or totally remove the complete crappy EGR system by installing a Week's elbow kit (Sasquatch Parts)

And diesels DO NOT require a blow off valve! That is a gasser thing and anyone who tells you it needs one is misinformed!
That subject has been beat slam to death before on this forum!!!! :roll:

Boost leak test

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