Laggy SSV/RPM?
 

My 04 rx8 seems to have like a laggy SSV valve or something, If your going thought the RPM from about 5-7 it losses a little bit of power and then it will all kick in and seem fine again once it catches up to it's self. It seemed to start after my front O2 came lose under my car and dragged on the ground for a little bit, when the O2 fell out the car was way down on power and you could hear the exhaust leak so I stopped and was able to get the O2 back in. Maybe a bad O2, but then I feel like the car wouldn't run well. I did press the brake 20 times to reset that but it still has it's lag. I need to find my check engine light reader that I seamed to misplace and make sure nothing is showing there just wanted to see here encase someone might know anything

When I experienced something like this it was a bad solenoid. The solenoid was working fine electrically but it didn't seal. For me it felt like the car ran out of breath somewhere around 5500-6000 RPM and then the power would come back around 6300-6500.

I don't remember which because I pulled all three solenoids together and forgot to label them. I tested the solenoids with a MityVac hand pump to pull vacuum on the port that connects to the vacuum accumulator and one of them didn't didn't hold vacuum while it was de-energized. Replaced that solenoid and the problem went away.

https://www.rx7club.com/attachments/...renesis-ve.pdf

Thank you, I was think that might be the problem as well, just wasn't sure. I will check that out.

HI,
did this help,
if so which one did you replace?

Ended up replacing all the solenoids and that has seemed to smooth out the rpm with out the drop in power. Guess the car was just never able to tell that it was failing because it still moved the SSV it just took longer to do so.

If it doesn’t hold a sufficient vacuum level in the solenoid vacuum tank then none of the three devices on there are going to work properly; SSV, VDI, Air Pump Valve.

My hunch is that solenoid leaks are often small enough that the air pump valve still works at cold start but the VDI and SSV valves don't at WOT.

Should be noted that you can always pull a vacuum on the tank first and see if it holds before disassembling anything. There’s a short hose with a green/white check valve between the UIM and vacuum tank. The check valve needs to be checked too. Under high engine load conditions the engine is making little to no vacuum in the intake. A bad check valve will let the vacuum tank bleed down back into the intake.

This is a good idea that I wish I'd had a couple of years ago... It will be my new go-to piece of advice for issues like this. :uh:

Hey Team,
im a douche and dont know if I can pull the vacuum from the before or after the check valve,
I tried pulling it from the white 90degree elbow on the intake near the accordion tube,
and it was fine,
but I think I might just be pulling against the check valve?

Yes, you made sure the check is holding, but to test the tank vacuum integrity you have to pull vacuum from the green “go” side (white is the “whoa” side, my way to remember) the same as the engine would from the intake nipple ...

https://cimg5.ibsrv.net/gimg/www.rx8...a0580dfbd.jpeg

Ah thanks,
Looks like its a fir bit more work to get to that,
I thought you meant the check valve just near the MAF sensore...

If you intend to work on this car the best thing you can do is buy a proper Mazda service manual for your model year

the online version was a very early release that’ s missing information and not reliable, but this is mostly complete

https://cimg0.ibsrv.net/gimg/www.rx8...2b997c292.jpeg

is there a guide step by step or video on how to take off these solenoids?

you need to make sure that the vacuum tank that the solenoids are mounted to holds a vacuum. Either a solenoid or the seal where the solenoids fit into the tank may be leaking. There’s also a check valve on the vacuum line from the UIM to the vacuum tank (see picture above) that needs to be checked to make sure it doesn’t leak. It’s green on one side and white on the other. The green side indicates the flow direction. Make sure you don’t install it backwards.


UIM removal

https://www.rx8club.com/series-i-do-...titled-196310/


testing valve operation

https://www.rx8club.com/series-i-do-...valves-174009/


removing SSV from LIM

https://www.rx8club.com/series-i-do-...-video-184663/


**special thanks to Jon for making all these DIY threads** :patriot:

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