I have no boost on the primary turbo, well it does show like 2lbs sometimes, but the secondary comes on strong. I also noticed a difference in exhaust tone when the primary should be on.. It sounds a little more lower pitched than normal. I allways thought that the primary had to boost 8lbs for the secondary to come on, but i guess this is an exception. Does any one know what this could be?

 

The 8lbs rule only really applies to "Fast Transition" between primary, and secondary combo. The fact that you are getting boost from secondary would indicate that your vacuum side of the turbo control actuator is working well.

The poor primary could be a number of things like a broken waste gate. Actually, I think that the waste gate would be the only thing that would cause what your are seeing. Check out the waste gate actuator and look to see that:

a. The Actuator rod is attached to the waste gate valve on the turbo manifold and...

b. That the waste gate actuator isn't fully extended and non retracting.

 

It sounds like a sticky wastegate or solenoid. You can't get secondary boost without primary boost, and the wastegate starts moving around at 4500rpm...

Have you checked the actuator and the solenoid?

 

i had similar problems. intermittently i would have no primary boost, seconardy boost would be fine. I replaced all of my vacuum hoses and now my boost pattern is perfect . There were a few hoses that were crimped, but I think the cause of my problem is that the hose from the y-pipe to the vacuum chamber did not have a check valve on it (stupid mazda dealers).

good luck

 

Well as strange as it came the problem just disappeared... For now anyway. Hopefully for good. If it happens again which is inevitable I check the solenoid and actuator. Thanks for the replys.

 

Actually, you can get secondary boost without primary because the secondary uses a seperate exhaust vein contorled by the turbo control valve. Yes it helps to have primary boost, but the reality is that you would only need one of the two hoses attached to the turbo control actuator to make it work (al long as either of them are in top shape). There would be no prespool to the secondary without the primary, but you would get secondary once the turbo control valve opened up.

 

The turbo control actuator uses primary boost and vacuum to open up to allow additional exhaust to flow to the 2nd turbo. Boost alone isn't enough to open the control valve all the way. Don't ask me why Mazda did it this way :p

 

I also had a primary boost prob, i think was caused by the ecu being in safety mode.

 

I just went throught this -

i was getting about 1psi on primary and max on secondary.

replaced the turbo control solenoid (the one with 2 lines coming out of it and under the manifold) and all problems fixed.

good luck

 

I believe this to be 70% of most peoples problems.