Cujo505

Hey all I just got a used 2004 rx8 about a week ago. Ive been going through the forum for just about everything but Im at a loss and just seeing if i can compile it all in here for some help.

I got the Rx8 and knew the pwr steering was hard and catalytic code p0420 was what they told me so i cut that off right away. Got it home and replaced the cat and the downstream o2 sensor pretty quick.
I love this car and ill keep fighting to keep it rolling.
Basically i have a CEL code i cant check yet and the coolant light is on in the dash. Coolant levels are fine and the car doesn't overheat or anything abnormal so im guessing thats a bad sensor.
What I'm fighting with the most is the car starting fine and driving fine for quite a while. After it is pretty warmed up if i come to a light it'll idle rough. First time this happened it died and i had to wait about 15 mins to get it back going and had to neutral stop while keeping the rpms up.
Most of what i have read is possible o2 sensors.. I could replace the upstream. Also debating on new ignition coils and spark plugs.. Also a good possibility.
Now on to the last part of the issue. I have a low amount of power when hitting the gas. It lags for a second then kicks in and gets going.
I guess what im wanting to know is am i on the right track with new spark plugs, coils, and upstream o2?

Apologies for being new to the forum and asking what im assuming might be silly questions but im happy to have finally joined. Im excited to get my car running hopefully for many more years. I keep telling my son he will get to ride in it soon and hes too excited.

Thank you all

Loki

iTrader: (1)

Not sure what you have read but that is classic compression loss. Nothing to do with O2 sensors.
Have a compression test but start planning for an engine rebuild.

Also the dead cat is probably what killed it. Dead and overlooked coils kill cats, dead and overlooked cats kill engines.
The previous owner did you no favours here.

Cujo505

I was hoping for a better outcome. I did noticed a lot of oil around the area of the fuel rails. Caked on wires, down low in puddles, etc. Oh and the lights flicker as it is trying to keep itself idling.
Without a compression test im not sure but could a bad seal or gasket cause the same symptoms. The engine just sounds really strong to be needing rebuilt but you would know bettet than me im just too hopeful.
My first thought from the beginning was apex seals.. Guess i should have started inside the engine first.
Thanks for the input . Its going to the shop soon. Ill be sure to ask them for the compression test asap.

CaymanRotary

It could just be a weak ignition system that's causing these issues, so don't think your engine is toast just yet. Make sure they have a proper rotary compression tester so you can get accurate results. From experience, anything over 6.0 Bar is fine as long as there isn't a huge difference in numbers. I know Mazda's minimum spec is 6.8 but I've run RX8's for years and thousands of miles with numbers below 6.8 without any issue. O2 sensors wouldn't cause a big issue like the one you mentioned so I doubt that is the cause. Also, if you did have a bad sensor it would shoot a code for it. The coolant sensor is inside the overflow bottle. So if the bottle is full, you will need to replace the entire bottle to get rid of the light on your dash.

My recommendation is to do the compression testing first, if it passes, go ahead and change out the coils, wires and spark plugs as this is likely the cause of your issue.

CaymanRotary

You may need to replace the battery or you could have some wiring issues. Best bet is to make sure the battery is healthy and both terminals are free of corrosion and that there is a tight connection between the battery and wires. Electrics can also cause these problems.

Cujo505

That makes me feel a little better although im planning for the worst and hoping for the best. That was my last effort i was going to try is new coils.
Now something ive been wondering. If the cat i took off had no honeycomb in it, could it have blown all of it into the muffler and backed it up? Causing my airflow to be bad and choke up the air system causing idle problems?
Just something i was thinking about but it could be way off topic, just curious if its possible?

CaymanRotary

Absolutely could still be blockage in the pipes. either in front or behind where the cat sits. When mine blew, my exhaust guy spent almost an hour taking broken cat pieces out of the exhaust pipes.

Loki

iTrader: (1)

Yep that has definitely happened. Given that you just bought the car I wouldn't take anything for granted.
Although that does explain the P0420 code. Maybe ask the previous owner if he had gutted the cat intentionally.

Cujo505

You guys are all very helpful. Thank you.
The last thing im curious about is the fuel system. The guy told me they had taken it to a mazda dealer and had a new fuel pump installed. I think ill take a look there as well. Im still believeing its coils or backed up pipes but im not too sure they didnt mess something up with the pump. Ill do some tinkering before it goes to the shop just to eliminate some possibilities i have wondered about.
Side note my power steering is tough. Got some connector cleaner ill try from reading some other threads but the steering doesnt bother me. I just want the thing to be driveable.
Again thank you all. Hopefully ill actually be able to tall about cosmetics in the future and not just engine issues.

Loki

iTrader: (1)

Steering is electric, so if the battery connections are poor (flickering lights are a sign), power steering will 'flicker' also.

CaymanRotary

I doubt it's the fuel pump, otherwise you wouldn't even be able to run the car for very long, if at all. You could do a fuel pressure test to check if you want peace of mind though.

Also, just wanted to throw in that it would be a good idea to clean the MAF sensor and make sure your air intake filter isn't clogged.

mazdaverx7

iTrader: (6)

The first thing I would do is a proper compression test with a rotary compression tester. What you are describing is an engine with low compression. I've been there and know the symptoms. My 04 Nordic Green GT does the same thing and the engine has low compression and is in need of a rebuild. I did the whole plugs, wires, coils, fuel pressure test deal but what I should have done in the first place was a compression test. Once I broke out my rotary compression tester, I knew exactly what I was facing.

CaymanRotary

Agree 100%, before putting any money into the car make sure that engine has life left in it.

Cujo505

Alright. After seafoaming the gas and driving around she died 3 times. Before this i noticed someome had broken one of those little inlet elbows on the intake so compression was lost there.
Replaced the elbow before doing all above.
Codes cleared now most recent codes up are.

P2259 secondary air injection system control B circuit low

P0661
Intake manifold tuning valve control circuit low bank 1a

P0031
Ho2s Header control circuit low bank 1 sensor 1

Guys i think my engine still has life left.. Compression test coming soon but theres all kinds of issues going on with the air.
From what i can see, someome has done work before and it looks like the messed up a lot of stuff they didnt know that they were working with..
Any input from here?

Loki

iTrader: (1)

All the 'circuit low' stuff is wiring problems. Possible a rodent has chewed up your wiring? You don't super need to worry about the air pump. It's there to warm up the cat faster and wouldn't affect your driveability.

The O2 sensor code basically means your front O2 is not working at all. It's not even powering on. See if there's a break before or after the connector for it. If it's after, you can just replace the O2 sensor, but if it's before, you need to fix the wiring harness. This also means your car is unable to learn fuel trims and probably dying because it can't properly learn.

But, none of the above explain why you can't restart the car for 15 minutes. That still points to compression loss.

CaymanRotary

You really need to do the compression test before any money is spent on my suggestions below.

The P0661 and P2259 are your three solenoids below the upper intake manifold attached close to the firewall. You will need to remove the UIM to get to them unless you got hands like an 11 year old. If changing those three solenoids doesn't fix it, likely your SSV is stuck and will need to be removed and cleaned (replace the thermostat while you are there). Go ahead and replace all 3 solenoids and see what happens but make sure you use Mazda OEM Solenoids. I replaced with the cheap Chinese aftermarket and they worked for all of about a month. The P0031 is your front O2 sensor near the Cat that will need to change out. Was likely damaged because you are running a catless midpipe.