Since about two years I got a fault code P0430 that show up about a couple of times per season. Decided to do a good boost leak check today. First I have found the change-over valve, besides the diverter valves, leaking at the base of the outlet tube. A couple of sense lines elbows leaking at the base of the throttle body attachment. But still a leak somewhere near the throttle body. Used my wife stethoscopes, took of the diaphragm at the end of it and only use the tube and the headset and locate a strong leak under the central part of the intake distributor. Took me a while to take out this intermediate piece but there was a small crack in the plastic.... I am now trying different glue to fix that because I don't want a pay $200.00+ for this plastic part....Tomorrow is another day

 

Nice finds. I would have never found that crack.

 

Before the remapping of the ECU I was doing the pressure test at 15 psi and it was holding properly (my max boost was .7 bars (10 psi). But since I boost up to 1.2 bars (17 psi) I have to do the test at higher pressure and many new leaks appear. I do my test at 25 psi, may be it is too high?

 

It should all hold.

 

Nice find! I think 20-25psi for the test is just about right. Personally, I do 20.

 

Ok, job completed , did a last decay and I don't know if it is good or not. Please let me know!

From 25 to 20 it drop in 1:36,
from 20 to 15 went up to 3:25,
from 15 to 10 6:06,
from 10 to 5 10:16,
from 5 to 0 over 16:00 minutes, for a total of a bit over 16 minutes

Is it good?

 

Very good.

It's not really about the pressure drop vs time... it's about hearing the leaks at approx 20 psi and addressing them. The slow bleed-off you documented doesn't affect your performance. Rest assured your turbos are not doing any more work than they have to. Green light baby!

 

Thanks Stebo!!! Happy to read that! Beer time