Diyman25

I have 2005 sports model with New Mazda reman less then 3000mile , and new Mazda coil&plug and wire

I build this car for track day, at beginning of this years when I took it to track , after 1-2 hot lap
The car will throw P0661 code CEL , no biggie
With 100k on intake Manifold and solenoid
I should do a refresh ,

Sure enough the SSV was pretty dirty , shop clean it and change OEM Solenoid
After I get the car back , no more CEL but I just feel weird car was no longer response sharp before , and feel slow !!!
At last track day I go, after review the datalogger
My top speed was slower then before !!!
Still no CEL, but this bother me too much
So I took it too dyno, when I see my 150whp print out
I was like **** no way , I have blown engine !!!
But car with perfect hot start and no blow by at all, I can't believe this is bad engine
When I doing research on forum found a guy have similar problem like I have , good engine
No CEL and was down on power !!! And Youtuber car throttle's Rx8 have similar dyno curve like I do
So I suspect I have SSV problem, I log my MAF S/G only showing 180at 9000rpm
That is wrong !!!! I have intake manifold issue

Then I borrow vacuum pump to open SSV for checking leakages, but only loose .2hg In a hr so the problem is some where else

But can't help dyno the car again !!!! Was so glad to see 18x whp , what a relief , u guys can see the compare before and after

Tonight I hook the vacuum pump to see how much vacuum solenoid will draw
Supposed SSV will open at 3850rpm but I don't see vacuum start close to 5-6krpm and doing test drive solenoid won't vacuum too it will draw 10hg for a split sec then jump back to zero

Now I suspect I either have bad solenoid or vacuum leak after solenoid!!!!!
From now on I will only use Mazda solenoid
Those made in china crap are all too risky

Diyman25

A dyno video of SSV open up by vacuum pump before and after

Beside power different, u can notice intake noise is different too

Diyman25

When I hook vacuum pump as gauge to SSV Solenoid ~

sinkas

SSV stuck shut?

TeamRX8

iTrader: (25)

It will only register a CEL if stuck open (position switch on actuator arm) or if the pcm detects high or low voltage on the solenoid

there is also a check valve in the vacuum hose line between the UIM and the solenoid vacuum tank that needs to be checked

Diyman25

It will parical open for brife time , then shut close again

Thanks~ for diagnosis direction
After SSV problem on dyno, I am thinking the old school way, like NA RX7 area time Force APV onRx8 is SSV open all the times, since on track u will hardly use any thing below 4000rpm~

TeamRX8

iTrader: (25)

Yeah, I believe Adax said that’s what he was doing. You may need to raise the idle to 1000 rpm or higher. It will be a low torque/response issue whenever the engine is below 4000 though, but more so for a street car than a track car.

as you dyno shows though, imo it would be better to have it functional for anything under 5500 rpm. It never really seems to fully recover the same as when the intake staging is functional.

.

Diyman25

While i am diagnostic SSV problem
I Take time to install Feed equal length header

And With more diagnostic suspect vacuum leak at
solenoid vacuum tank

Diyman25

Problem Confirm !!! there is leak on tank