im having problems with my primary boost... please dont send me the link to trouble shooting, i already searched it.

"if your getting full boost on secondary turbo, you do not have a boost leak"

IS THIS TRUE OR FALSE.???

IM TIRED OF SEARCHING FOR BOOST LEAKS IF THIS STATEMENT IS TRUE. i will start searching other issues. my rmp gauge works when it feels like it so its kinda hard to tell sometimes, but it seems like im getting only 5-7 on first turbo, then it shoots to 10psi at 4500rpms. my car is an automatic with a full exhaust, and its hard to tell because the transition is so fast whats going on. i do know that it will not make 10 psi until i hit 4500.

 

True. Actually, I think I said that

I would start by replacing the check valves. They are notorious for causing primary boost failure.

 

thanks. yes i quoted you somewhat. anybody have a link to check valve locations? i will search in the mean time. thanks

 

one more question. where can i get the new check valves? mazda dealer? what exactly do i need to ask for? how much is it gonna cost to replace these?? whoops i meant 4 more questions////

 

Dale Clark sells Viton check valves, 4 for $15 shipped. http://www.clubrx.org/default.asp?id...ntent=26&mnu=8

I would start by diagnosing your problem with the workshop manual. Just because check valves commonly fail, doesn't mean your's have.

 

what about something causing the wastegate to remain open? this would dump the primary's boost, whilst allowing the secondary to help overcome this once it comes online... just a thought.

 

I have a copy of the vacuum hose diagram on my site:
http://www.davidgeesaman.com/

 

In order to achieve 10 psi at high rpm, both turbos must be working properly. Since you are (I assume) able to do this, you don't have a boost leak, or a bad turbo. The problem is getting the primary to actuate right. Starting with the simple things, like replacing cheap check valves, makes sense to me.

 

FALSE FALSE FALSE, it is possible to have a leak and still make 10psi. As long as your primary makes 7psi it will allow the secondary to come on line. Even tho it makes 10psi with both turbos doesn't mean you don't have a leak, just means they are running harder to compensate for the leak.

 

While I haven't experienced it myself, I recall in the past where others have had a "primary" boost problem that was solved by fixing a boost leak.

I believe that could happen when the leak can only flow a certain amount of air, and when it's the primary running alone you'll see a drop in boost. But then when both turbos are running, they together have enough capacity to compensate and get the system back up to 10psi.

All theory aside, starting each boost troubleshooting with thorough inspection for leaks is simply a smart thing to do. It's never a waste of time.

Dave

 

thanks. i have throughly checked for leaks before i posted this thread. drove car today. its a solid 7 psi on the first turbo then goes up to 10 instantlly when the second turbo comes on. when i bought the car two solenoid wiring harnesses were switched. there is a very good chance there is a backwards check valve also. i will report back. thanks for the diagram.