buxton

I recently lost some boost pressure and have checked every hose and connectiopn I can find. I have removed the j-boot and it is fine. I am running 951 max chips and a reliaboost that was set to 16 psi. Now when I get into boost the highest it will go is 12 psi and falls off fairly quickly to 8 psi.

My wastegate is shimmed. I took off the line to the wastegate and was able to blow air in and suck air out. Is this normal? Can a wastegate go bad that quickly where it worked fine one day and not the next? If it is not the wastegate where should I check next?

I couldn't physically reach all the hoses under the intake. If I pressure the system where should I do it? Which hose should I disconnect and add pressure to and how much air pressure?

Van

I pressurize with half of an old fuel filter housing with an air nipple stuck in the J boot where the air flow sensor goes.

My guess is that it's one of the following:
-Leak in intake track
-Broken valve seat in wastegate
-Broken vane on turbo
-Boost controler failure (I assume you no longer have the stock cycling valve)

kevincnc

If you mean you disconnected the line leading to the wastegate from the pressure source and blew throught that line into the wastegate, it seems that the wastegate diaphram must be broken if the line isn't.

reno928s

Theres one on Ebay and I know the seller personally. http://cgi.ebay.com/ebaymotors/ws/eB...147310689&rd=1

kevincnc

Umm, never mind- if that was the problem you would get too much boost unless the wastegate is stuck partially open also.

buxton

I pressurize with half of an old fuel filter housing with an air nipple stuck in the J boot where the air flow sensor goes.

My guess is that it's one of the following:
-Leak in intake track
-Broken valve seat in wastegate
-Broken vane on turbo
-Boost controler failure (I assume you no longer have the stock cycling valve)


Van,
1) I thought that I would find a vacuum leak also. No luck yet but will keep looking
2) If I can blow and suck air through the wastegate is this normal?
3) When I had the j-boot off the vanes on that side were good. It spins freely with no play.
4) I have the Reliaboost installed. Can they go bad somehow? How would I test that?

kevincnc

You should definitely not be able to blow or suck air through the wastegate line. The diaphram in the WG is probably broken, which could explain the sudden failure. It is strange though that you are getting low boost instead of overboost because the line you are blowing through helps to open it and bleed off boost. If you can blow through it, it's not helping the wastegate valve to open. So I'd guess that the broken diaphram is somehow jamming the valve open a little, bleeding off boost.

Thom

I had a similar issue and it was the reliaboost. Throw it away as far as you can and fit an accuboost.