October 1, 2011

Engine Issues Resolved

I was chasing down a "gurgling/fluttering" noise at 8,000RPM for a little over a month recently. The noise was very noticeable and had gotten me very concerned, so I could simply not ignore it. After a lot of digging around and countless times of ripping things apart, I figured out what I was faced with. The interesting part of this however is that not only did I figure out the problem, I learned that I was chasing 3 separate problems. I thought I would share my findings with everyone, just incase someone should run into a similar issue.

1. – Secondary Shutter Valve (SSV) – The SSV works off of vacuum pressure and is a valve that opens at right about 5,000 RPM. When it is not opening properly, it’s like hitting a wall at 7,000RPM… literally (pretty scary might I add…). I am not 100% familiar with how it works, but from what I gathered, the SSV has a lot to do with how Renesis rotary engines utilize the 6 intake ports for maximum power output in higher RPMs.

Upon some research, I had discovered that others have experienced similar noises when they had turbulence in their intake. After dismantling a few things and taking a look into the lower intake manifold (LIM), I could see the SSV and noticed it was completely gummed up. With help from my RX-8 Club buddies Andrey and Francesco, we followed the Mazda Technical Service Bulletin (TSB) on how to remove the SSV and clean it. Francesco brought his clean one so we could do a quick swap. Compare the two in the picture, talk about a huge difference! (Mine on left was actually half cleaned already too).
The TSB calls for a newer type of replacement gasket on the SSV, and a much longer bolt as well (which didn't fit for some reason..? At least for me it didn't). In total it was about $10 from the dealership, so be sure to pick that up first before doing this project. Something interesting that we had noticed is that the area where the SSV sits in was gunked up as well. This included the point in which the SSV rotates off of. We had made sure we cleaned it all up with carb cleaner, and then lubricated the rotating end of the SSV with white lithium grease to help ensure the SSV will not get stuck and continue to open smoothly.
After replacing the SSV, we had placed everything back and made sure things were nice and tidy. After a few test drives, the noise was gone and the car actually felt much better than before, making me wonder how long the oil was building up. This is definitely not a job I’d like to do ever again, so I added an oil catch can to catch oil from going into the intake manifold again.

Big thanks to Andrey and Francesco for all the help with getting this done. Be sure to check out Francesco's blog post about our work on the SSV.

2. Misfiring– Ignition Coils – Unfortunately, my BHR ignition coils were failing and had ruined my spark plugs very earlier than expected…. As in within 3,000 miles. If I had a timing light, I could have tested more accurately, but instead I swapped BHR coils with someone else and the misfiring had stopped. Thanks to Ray at Black Halo Racing for swapping out my bad kit as quickly as possible and getting me back on the road.

3. Running Rich and Misfiring - Intake Screens/Alignment – A simple fix that I cannot stress enough to anyone else… USE THE SCREENS THAT CAME WITH YOUR INTAKE AND MAKE SURE THEY ARE FLUSH/STRAIGHT. They are there for a reason. That reason is to smooth out the air flow over the Mass Air Flow (MAF) Sensor so that it accurately reads what is going with your air flow. My intake tube was not straight enough, and my screens had become dislodged when assembling the intake, causing the car to run terribly. After reassembling everything properly and cleaning the MAF just for kicks, the car was running strong again.

I hope this helps out anyone in terms of trying to diagnose misfires or odd sounds, as I really did not have much information to work off of other than my gut and some advice. Feel free to leave me messages with questions if you are running into your own problems as well!

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