Alright guys,

per your recommendation I checked over my engine and still cannot find the problem. New coils, plugs and a decarb.

At around 4k the engine makes a loud throaty noise much like vtec on a b16 POS and it has less power. It happened during some spirited high rev driving, it suddenly started making this sound after a touch of 8k or so.

Please look at the videos and tell me what you think it could be, also if its determined the motors bad and the compression test confirms it on Thursday does anyone know where to buy a 13B-MSP thats built better than what id get from mazda?

( im at 117,000 on the odometer on second engine, dealer didn't specify when new engine was fitted)



http://www.youtube.com/watch?v=DcmQD4MNVZ4

http://www.youtube.com/watch?v=YHzSmL0RvRo

http://www.youtube.com/watch?v=3wcqPElvzIo

 

1) Don't constantly redline your engine if the CEL is flashing.
2) Since you have a CEL, what is the code being generated?
3) Have you cleaned the MAF?

 

maybe its your tranny ? does it do that in every gear ? could be a slipping clutch or maybe even your differential , it does not seem to be an engine problem.. we had a guy at my old work come in with an rx8 where it could not rev past 6000rpm , and that was due to his gears being all worn out and slipping. do you drive it hard`? burnouts ?

Jon could be right when i got water in my MAF ( speed intake is very low to the ground, can't even go throu a car wash lol ) it would not rev past 6k and start to choke. take out your MAF and see if its damp or real dirty lol have you changed your air filter ever :S lol

 

Sorry for the lack of detail.

The CEL is p0300 and p0302, which I have gathered is random misfire and rotor housing 2 misfire.

I was only redlining this for the sake of the video I have been painfully babying her since this issue came about.

I have yet to clean the MAF sensor because I dont have cleaner at the moment, I will try this during down time.

@ speed__8

The engine makes the noise while im sitting with the clutch disengaged so I do not think it is tranny related or diff, although it did start while drifting a corner in second gear. The noise comes about at any point I rev past about 3 to 4K, it will also not make it at all sometimes if I am driving very safe and sometimes it will make it no matter how I drive if I reach the listed rpm.

 

Also I do drive hard once in a while, at least a red line every start but rarely do I burnout. At $245.00 a tire I tend to not burnout, I do let the back end come loose on a more frequent occurrence though.

Probably should have drove granny smith style more often I guess...

 

Reason I asked about the MAF is because I've heard similar sounds because of it.
The speakers on my phone isn't the greatest, but it sounded like when my MAF got saturated with water (your's could be oil though).
Similar sound and my CEL also flashed.
MAF cleaner is cheap and easy to do... might as well rule out the simple ****.

 

Yeah I will certainly clean the MAF, its not the plastic electrode bulb but the inner part up top I need to concentrate on correct?

I am just finding it hard to believe its something so simple, this sounds is like nothing I have heard before. It seriously sounds and feels like a k20A2 hitting vtec.

I guess the MAF could cause excess fuel or similar to cause irregular combustion?

On a side not while I take suggestions and follow through with them, does anyone know where I can buy a pre-built MSP to drop in that is built with quality parts? I am expecting to pay $3k for a replacement?

 

https://www.rx8club.com/showpost.php...71&postcount=9

And while you're cleaning the MAF, peak inside the intake and see if there are any fluids in there.

 

Sounds like an exhaust leak or vibration from exhaust to me

I would get someone to rev the car while up on stands and go over it trying to locate the noise .

 

When I took the intake off to get to the e-centric shaft for the decarb I did notice some yellow jelly like substance in the accordion tubing. I figured it was a way the engine lubricates or something and that this was just from a long time without cleaning?

It certainly sounds like an exhaust leak but I cannot hear it from the exhaust under the car while it is revved nor from the exhaust header. Is it possible the cat is clogged up and its a back pressure sound? This would also cause the misfire No?

 

If your name is Jim, I have a 3 word, Star Trek quote that comes to mind...

 

the intake should be dry.
You should not have any "substances" on your finger if you finger-wipe through the intake.

 

Yeah this was a yellowish substance not unlike Vaseline or something.. It has collected in the ribs of the tube.

What could this have come from?

 

We see "milky" substances on the oil dipstick from condensation.
Almost sounds like that...

 

Yeah id call it milky.

I have never seen this on my dipstick though, always nothing but oil. Im in Florida so I don't know how id get condensation from the intake side of things?

 

Does it have a stock catalytic converter?

 

yes and id say its the original.

I had a bad o2 for a while and finally got the time to install a new one, while at it I did the plugs and recently the coils.

The cat could be bad but im wondering if it would make this noise, it honestly sounds like something is loose in the engine such as a rotor.

 

I know it might be hard to say, but have you noticed a decrease in power?
After a nice drive down the freeway. Stick your head under the car, about midway down and check for a glowing cat. Best results are obtained at night.

MAF and accordion tube should be removed and thoroughly cleaned.

Oh and if a rotor was loose. You'd know it.

 

I'll check the cat tonight and see if it's getting that hot. Also I'll clean the maf and intake and report back.

"Oh and if a rotor was loose. You'd know it"

I love the experience here, I admittedly don't know the feeling of the engine enough to tell what's broke and what's not. I'd probably be able to sell her right now to some kid off craigs list and tell him " yeah give it some gas man, you here that powerband after 4k kick in?"

 

Just an addition, I noticed during warm up the car is making the noise much sooner than 4k. Also after warmup it resumes to only start at 4k and sometimes not at all.

Also why would the clutch pedal loose pressure while this noise is being made? Its not a drastic loss but enough for me to feel it as I hold the clutch in during the rev.

 

Update for you guys.

I cleaned the maf and the intake tract. I did notice a slight improvement in idle which is now at about 800 id say. Also I don't have any starting issues cold or hot, the car does start right away.

Worth noting that when the car started this noise I also started getting a noise while the starter is engaged which sounds like rattling but then goes away as soon as the crank is done.

Also the cat does not glow after a highway drive.

http://img156.imageshack.us/i/dsc0532l.jpg/

http://img190.imageshack.us/i/dsc0536i.jpg/

http://img813.imageshack.us/i/dsc0538o.jpg/

http://img577.imageshack.us/i/dsc0540z.jpg/

http://img402.imageshack.us/i/dsc0541d.jpg/



Please help me out guys, I am desperate here.

 

Jax! Figure this out for all of us. My car made this sound once, but in all my searching, I have never found an answer. This is becoming common. Sadly my car is away for winter, so I cant test anything. But it sounds just like your car, almost like a subaru(kinda sorta).
Mine had no loss of power or CEL, and only happend in 2nd-5th gear.
I was thinkin it could be 4 things:

1) Fuel pump(not enough pressure to push fuel in)

2) Cat(Gets hot and clogs?????)

3) Motor mount(exhaust leak???)

4) Engine

 

EXACTLY!

Its throaty and loud, it almost would sound good if I didn't cringe knowing its not normal and also feel the pair loss of power syndrome. I could seriously sell it to someone unknowing but I cant introduce someone into the mazda family like that, id feel horrible

I can add one thing to the list of possibility's.

5.) Secondary injectors, they kick in at 3750 rpm and that is about when my noise comes in most of the time....

I am hoping its not something loose inside the engine and am optimistic as someone has stated on this thread it would be a much worse and consistent noise which it is not. The only guaranteed time it makes the noise is if I get on the throttle, if I baby it and shift at least by 5500 rpm it usually does not make the noise. If I do force it to make the noise it will make it after 2k regardless for about 10 minutes of driving.. then go away again with continued granny shifting.

Shes going to duval mazda at the avenues tomorrow while I eat at bono's so lets hope for the best and expect the worst.

 

I'm beginning to think it could be a sticky APV in the lower intake manifold. That would explain loss of power in higher rpm's. Noise coinciding with secondary activation. A lot of fuel and no air would make that throaty type noise.

 

Elaborate on your driving characteristics a bit more please.