When you do this test from the air filter, does the intake manifold gets pressurised even though the throttle body is shut?

I have a P1109 that doesn't want to go, tried an other MAF and didn't work, did a boost leak test, found a bunch of small leaks, repaired them all and i still get the code.

Car runs good but when i get over 0,7bar (car usually runs 1,4 bar on meth on A28) the car will cut with which seems like a ECU protection.

I am out of idea but was wondering if when i do the test if the other side of the throttle body actually gets pressurised, i might have a leak on the other side? If not, how do you do that? Markski?

thanks

 

Markski is shaking his head lol

Its a process and you really have to rule out one thing after another...
forget the air box... you need to do the test from the lower boost hoses.. I have enough threads on here... read up and just do it.. dont over analyze... just do it... you will find drama.. then tell us what found...

 

what is wrong with testing it from the air box? I had a kit made for that, i guess i'll need to make a new kit...

that would rule out the problem of the oil cap leaking the air though...

 

By pressurising from the airbox there are several things you might miss.
First of all you will have a huge leak towards the fuelvent.
Also you will pressurise both ends of the DV's meaning you will not see if they are leaking.
Probably lots more reasons also.
So have that kit remade

 

Forgot to answer:
When you do this test from the air filter, does the intake manifold gets pressurised even though the throttle body is shut?

Yes it will be pressurised through the fuelvent system, there is a oneway valve there which will allow pressure from the inlet hose and in to the intake manifold.

 

just check markski threads - hes an expert when it comes to boost leaks.

 

it's just soo much easier and answers so much more from jump to begin at the turbo inlet! why begin where you know there are potentials for more leaks!? that is counterintuitive at the least!

 

do it from the lower boost hoses and stop arguing... trust me... JK

 

yeah i am pretty positive i found the leak this morning, i realised that when you pressurize from the air filter you can find the leak to the atmosphere but you can't check the DV (like Ronny said) and from what i found on mine, i had a check valve that didn't work. It was sending back the boost towards the little hose on the driver side inlet piping. So i am 95% sure this was my problem. I wasn't able to find it with pressure at the air filter but i made a new kit to pressurize to the intercoolers and found it pretty quick.


Part is ordered


thanks Markski

 

Good man . This stuff is easy just had to be done right.