kanie12

Have an rx-8 2004 with 2011 engine with approx 43000 miles(70000km) with power/noise issues. Here are the symptoms:

* Noisy airpump (I think), sounds almost like this but not that high pitched https://youtu.be/FdsGaF59ka0. It goes away after few minutes of startup
* Glowing O2 ring after rough driving
* When the engine is hot, it has intermittent power issues and a strange "roar", like it's not getting enough fuel or air when accelerating hard.
* Car seems to get very hot and there's a clear smell of oil at that point. Specially after a long trip.

Mazda can find no fault with the car and claim glowing O2 ring is fairly normal.

I have newly replaced the following:

Original mid and back exhaust system with cat(never replaced the short pipe directly from engine), coils, wires, plugs, fuel pump, throttle body , aluminium coolant tank, radiator and maf.

Here are the good signs:

* no white smoke
* very stable idle
* will start when hot no problem
* no stalling
* no cel
* fairly stable oil usage

Can someone help?

Loki

iTrader: (1)

Glowing cat = destroyed cat. The hesitation might be the engine struggling against to push exhaust out through the clogged catalytic converter. Take it down and inspect it. If you continue to drive like this, you will destroy the engine. So.. whoever at Mazda told you that's OK, is wrong.

You also don't have a 2011 engine, it may have been put in in 2011, but its a 2004-2008 engine.

wannawankel

Loki - I agree it might be the cat. Plug in an OBD2 reader and check your temperature readings against those on the site for the Series I engine (2004-8).

kanie12

What temperatures should it be if it's normal? The cat was recently replaced. Could bad wiring/plugs/coils damaged it? Is there any odb2 reader you guys recommend? Thanks

NotAPreppie

Bad coils/plugs/wires will cause misfires which can kill the cat.

kanie12

Just bought the simple Bluetooth ODB2 reader. Here is some numbers after idling 10 min in fairly cool garage:

Idle: 815-830 rpm
Coolant temp: 96 celcius(205f)
intake temp: 71 celcius(159f)
acceleration vacuum: 19000 in/Hg
no current or previous error code

NotAPreppie

What are your fuel trims? Depending on the app, you should be able to read the catalyst temperature.

Your intake temperature is really high.

Loki

iTrader: (1)

That's not the necessary information. You want catalytic converter temperature, it should be around 900C/1600F at cruise. Measuring it at idle is not useful.

kanie12

Bought pro version og the app(torque).

After 20 min drive no higher than 110kph(70mph).
Cat temp between 600-700c(1112f-1292f)
Keep in mind outside temp is no more than -6c(22f)
Regarding intake temp, i have k&n typhoon 2, could it be the reason?

I'll post more readings later. There is definitive hesitation and strange resonating sound at higher rpm.






Just scrolled through the newbie section and I'm thinking:

front O2 sensor failure (too rich)

• chokes as revs increase , also running to rich would give o2 glowing ring? Not long ago was driving for more than 2 hours and I experienced a heavy choke when I pressed accelerator hard in 1st gear and choke/roar like sound.

I do not see any hesitation when revving in idle.

kanie12

Inake temp much lower today?? Weird.

Loki

iTrader: (1)

I repeat, glowing cat = destroyed cat. If you take it down and it's still fine, you are in luck. I would stop driving until you confirm it's ok.

Thr Typhoon is a terrible intake, it has caused many headaches. If you can go back to stock, that might be best for now. Or forever.

Case in point: at speed intake temp should be a few degrees above ambient, not 31C

kanie12

[

Yea i know, but im trying to find the reason why car running so rich, aleast it seems so. If its running rich then cat is heating more than it should. But the readings i did lately show temps are in the normal range hmmm.. I will consider getting a decat. Can someone recommend a decat with least ammount of noise and great quality? Cat is not always glowing, i only seen it doing that couple of times, and its just where the O2 sensor is, not the whole cat.

Im also wondering if the exhaust manifold could be clogged, this part has never been replaced since 124000 miles

NotAPreppie

I finally looked up the design of the K&N Typhoon... Oh for the love of Christ! Who thought that was a good design? If you can't go back to stock, replace it WITH ANY OTHER INTAKE. Mazdaspeed/AEM, RacingBeat, a random collection of PVC... Whatever.

In the short term, I think you need to figure out why your IAT is so insanely high. The IAT sensor is inside the MAF. The MAF sits in a constant stream of air. So, you're either sucking in hot air from the engine bay or your IAT sensor is bad.

To test this, before starting the car for the first time of the day, turn the key to "Run" but don't start the engine. Fire up Torque and check your IAT. It should be pretty close to the ambient air temp. If it isn't you've got a problem. If it is, go ahead and start up the engine and see if the IAT climbs rapidly after the engine heats up.

What do your fuel trims look like?

I can't see how your exhaust manifold could be clogged.

kanie12

Thanks i will try measuring IAT before starting car like you suggest. I will also replace intake with Mazdaspeed/AEM, RacingBeat. Should i do a longer drive to get fueltrim?

NotAPreppie

I would avoid driving as much as possible until you have a chance to check out the status of your cat.

It's relatively easy to do a basic inspection.
Lift the passenger side of the car. Support the car with jack stands while you are under it.
Remove the two crossmembers.
Remove the rubber exhaust hanger for the midpipe.
Remove the three nuts from the flange where the header meets the cat.

There should be enough flex in the exhaust system for you to pull it down a few inches and shine a flashlight into the cat.

Loki

iTrader: (1)

Fuel trim at idle, once the car is warmed up, will give an indication if you have a serious problem.

The other reason you may be passing too much fuel is an ignition coil died. I know they're new, but what make are they? Some of the cheaper random coils off ebay/amazon have been known to be die on arrival.

NotAPreppie

Agreed, one of these is a cheap and easy way to test them...

kanie12

Fresh Mazda original rev C coils. How bout that front o2 sensor, i could try to get that replaced first? I'll check fuel trim at idle!

some nice rx8 vids:

https://youtu.be/ebncN6dg16k
https://youtu.be/B9bQq28tlXc brap brap 😁🤣

kanie12

Here are the fuel trim readings:

Cold start and 10 min idle:




10 min drive then idle:

Loki

iTrader: (1)

So you have a sizeable vacuum leak, or the MAF sensor is lying. Fuel trims should be zero and you have +14LTFT while warm. Also your O2 sensor is pegged at 1.0 which is a little weird. It may also be lying.

kanie12

So it's running lean? I was thinking that a while ago, that's why I changed the fuel pump and maf. So should i give it straight to the mechanics? They haven't solved this issue for several months.... seems like they never use odb2 meter unless there is a cel 😥
My last engine blew up cause of faulty cat and shitty mechanics.

Loki

iTrader: (1)

I'm sorry, I misread, it's not 1V, it's 1 lambda, so same as 14.8AFR. So that's fine. Your probably have a vacuum leak. If you say the intake has been apart for MAF replacement, I would start there. It doesn't take much...

.. which doesn't explain the cat cooking, but it's an easy thing to verify/disprove to start.

Would be good to record the reported airflow as well, in g/sec

kanie12

Ok. Will post g/sec readings, thanks!

kanie12

New readings:

Cold start and 10 min idle:



5 min drive then idle:

Thanks for all the help so far!

wannawankel

How about the IAT BEFORE you start the car. I didn't see that above.