Boost Spike issue

Carlos E

Member
:
Mazdaspeed 6
Ok so I have 20000 miles on my MS6 and so far I love the car. Recently however the car has been over-boosting like crazy!!! I was on the turnpike when it first time it happened and I noticed the boost went from my normal boost setting of 110Kpa (15.9 psi) to like 180Kpa (26.1 psi).
Keep in mind I have several mods to my car. Those I think might be relevant to the problem are: HKS blow off valve, HKS electronic boost controller and maybe the cpe intake.
Since I first experienced the problem I have re-done all the vacuum lines twice and replaced the HKS boost controller for a Greddy B-spec II because after I replaced the lines and seeing it didnt help I assumed it was the solenoid to the boost controller. Since I replaced the solenoid the boost hasnt peaked to the extreme of with the HKS unit but I also have been reluctant to increase the gain on the controller past about 20%. Even with this though I am seeing irregular pressure, normally it will be about 13psi but under some conditions it will spike to around 15.6psi.
Today I ordered the vacuum chamber (which sits below the intercooler and attached to the top of the intake manifold) the solenoid which is housed inside the chamber and the fuel pressure regulator as I think I might have I vacuum leak from one of these.
Any input on this matter will be greatly appreciated. Any theories or ideas as to what I might want to check next? I am especially interested in whether it is even possible for the turbo in the MS6 to develop 26psi even for a short time.
Also I am sorry if I posted in the wrong place but I am not very familiar with this forum and truly I am at my wits end trying to figure this out.
 
Sounds like the wastegate actuator is bad. If the diaphram gets a tear it will cause spikes. If you blow in the vac line to it, it should not bleed off.
 
Sounds like the wastegate actuator is bad. If the diaphram gets a tear it will cause spikes. If you blow in the vac line to it, it should not bleed off.

i believe he is on to something! lol.

but wow 26lbs on a stock turbie..good power?? lol. i don't doubt the turbo can push that pressure, i just doubt its giving the car anymore power cuz that way way out of its efficiency range.
 
First of all thanks to shane!!! I think you might indeed be right. But so now get this... Mazda does not sell the wastegate actuator independently from the turbo and the whole thing is $1300...convenient? hmmm.
Any idea where i might be able to find just the actuator?
 

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