High RPM (Bucking and Hesitation) (VIDEO)
 

Hey all. Sooo, I recently replaced all my spark plugs, coils, wires etc. I did my best to clean the ess (I'm not sure I cleaned the right thing (picture below, yay or nay?, this was after my attempted cleaning... :()
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And I cleaned the maf and bought new screws to hold it in place. I also cleaned and fixed the dismal airbox issues (weird filter and sand everywhere)

I did the 20 brake stomp reset although I'm pretty sure for the series II all I needed to do was to brake stomp once. I then did the re calibrations and it was all good.

On the bright side
- No more misfires
- More power and torque down low
- Smoother acceleration
- Better sound

On the down side (although this happened before too)
- Lots of white smelly exhaust smoke on first start up
- Still bucks super bad at the same consistent high rpm. I can push through it all the way to the beep if I try too. The video just shows (very badly) the type of bucking it is and the rpm when it happens.

So I read in the symptoms and the other threads that it could be the ssv, or fuel pump as I've ruled out most of the other symptoms through replacing them. The battery was just replaced a couple months ago too as was the starter.

I'm hoping it's something simple I forgot to do, or missed. I also took a picture of the top of my airbox because there is a hole that I'm not sure was exposed before and I just wanted to make sure it's nothing important.

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Here is the video ( Sorry the camera jerks away, I just did this on a whim and it jerks pretty bad and I couldn't keep it steady, that revving you here isn't me, my foot is to the floor, that's the bucking)

http://i1241.photobucket.com/albums/gg508/ds08tf/IMG_0834_zpsc23d5828.mp4
I have a couple other small issues as well (dirty inside the tail lights, missing bolts/sheared bolts), should I post a different thread for each issue? Or make one thread for all of them? Some of them I still have to research a bit more.

Thanks again for all your guys help! Without you yesterday and this morning would have been much harder but with you I was successful in my first diy work on my rx8! :)

That hole in the top of the intake is for a vacuum line, and missing it means that you both have a HUGE vacuum leak, AND whatever vacuum line it supposed to 'power' is not receiving vacuum and it's purpose is not functioning. I'm not sure what that line is for on the Series2. The vacuum leak alone will cause significant problems all over the rev range. You need to get that fixed asap.

I don't have audio on a PC that i can also view the video, so I can't comment on that, but with a vacuum leak that big, it will be doing all sorts of nasty things to MAF readings and fuel trims. Get that plugged at a minimum, or plumb the proper vacuum line in, then make sure you reset the fuel trims again, let the car idle for 10 minutes before driving, and then see where you are at.

So I've looked everywhere under my hood and have failed to find any loose tubing. I know judging from the diagrams I found online that the tube missing should go to the fuel metering oil nozzles... but no luck actually finding any tubing... is it possible the tube is completely missing? I feel like I'm missing something...

GAH! This is so frustrating. I took out the battery box and the airbox and can't find anything!
Please help!

I have the same "hole" in my car, and have seen images on the web (of series 2 cars) in which there is either the same hole or a plug. I have gone through the workshop manual and it's inconsistent with regards to if the series 2 has anything here - some diagrams show nothing, others show the same as the series 1, and others indicate the presence of a connection here, but do not show anything being connected.

If you shine a light into it, it appears to terminate and never enters the intake system. I too would love to get some closure on this once and for all.

There should be a plug on that hose. I can take a picture of the one i have in my basement. Remember the S2 has 2 vacuum lines connected to the intake (the 3rd one on the S1 was used to go to the oil filler neck). There should be a little plug on there.

edit:

https://lh3.googleusercontent.com/-m...002_204029.jpg

Is it a big deal if I don't have that plug? Can I just use a piece of electrical tape or something jimmy rigged?

Also any comments on the video or what it could be then?

-D

I'm going to watch the video now, but i wouldn't use tape ... last thing you need is it to get sucked in from the vacuum pressure.

edit:

That surging is definitely indicative of a vacuum leak. The car is making guesswork of the air that is coming in while in Open Loop. Because that leak is post MAF, you are pulling in unmetered air. Get that leak fixed asap.

I agree that what you are describing sound exaclty like a vacuum leak or a fuel cut. (Edit: can't watch the video on my phone) And based on what you have described regarding how you found it, I would continue on th le vacuum leak trail.

Vacuum leaks can be a pain to locate, so look over everything and make sure it is all tightly connected.

Unfortunately, we can't inspect your car for you through a forum.

I'd say it's pretty obvious where the vacuum leak is.

I had one once that was a tiny <1mm pinch in a gasket between the upper and lower intake manifolds. It threw off fuel trims by 5% and was allowing ~1.5g/s of airflow through that tiny point.

The massive hole in your accordion would be wrecking havok...

Update:

I will be going to buy a plug from Partsource (Canadian version of Autozone) tomorrow. While I was on the highway around 7500 rpms my engine light started flashing. I shifted up and it went away... didn't bother trying it again. I assume it's indicative of a vacuum leak and as such I will be very careful.
-D

Well the flashing is a misfire....

Dont drive the car hard before fixing that leak. You will most certainly cause damage to the engine.

Yes a misfire for sure. Flashing = misfire. I just meant one of the possible causes of a misfire is a vacuum leak.

If the accordion is the same as the series 1 part, then yes, certainly. I think there was some uncertainty about that when I posted. It should be easy to stick a probe in there to see if it protrudes into the intake area.

Edit: Saw the post saying you're going to buy a plug :)

Update:

I went to partsource. No plug that matched or that I could find and when I called Mazda they had no idea. There are three mazdas in my area so I'm going to go to a different one after school.

On the other hand I took a picture inside the tube and it looks like it terminates before the intake.

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Either way I taped a make shift cap that won't get sucked down overtop and reset the NVRAM and it drives the same. Same jerking at 8500 rpm.

Any suggestions as to what else it may be? Should I still think it's a vacuum leak? Or maybe a fuel pump pressure difficulty when the load becomes too great?

It's possible. Do you have any way of measuring the fuel pressure during your drives?

Also dumb question: Did you properly torque down the spark plugs? As stupid as it sounds, ive had weird crap happen to me when i didn't torque down the plugs enough the first few times i did replacements.

I just tightened them by hand and then just tightened it down until I felt resistance. I'm debating going back under and tightening them up a bit more. Is it ok for me to do that? Should I remove them when I do it and spray them with a sensor cleaner or anything? Or just remove the plugs and tighten it up properly to torque spec. I had like 3 extensions on the ratchet just to get it to reach. Not sure how accurate my previous torquing was.

Ps thank you for all your feedback and help :)

The rule of thumb is 'hand tight + 1/4 turn'. I knew i didn't get anywhere close because I removed my spark plug and noticed the crush washer didn't even have a scratch on it :lol:

I wouldn't be doing those High rpm runs with my fuel light on either ...

So the car misfired today on start-up. Not badly at all no noticeably weird idle. Just a firm crank and then the light flashed and stayed on. I scanned it and it came back as a Cylinder 1 misfire again.

So you said you already changed coils and wires. You didn't accidentally mix up L vs T did you?

Shot in the dark, is it possible the previous owner removed the VFAD while messing around with the intake, and forgot to plug the VFAD vacuum line?

Side note: that hole on top of the accordion seems to have an exit in the bottom of it, so it's not fully closed. But it also seems full of some yellow crap, which would suggest that there isn't a crazy amount of airflow through there.

Other thing. Do you have a picture of the old spark plugs you pulled out? Could tell us something.

I'll take pics tomorrow. They looked in pretty good condition actually. As did the coils...
Either way I'll post em up. I'm gunna google vfad stuff too to learn more.