Thump

Hey guys newbie here to owning a rotary. Just wanted to introduce myself and ask a question. I just purchased a 05 rx8 103xxx miles. It still starts and drive but not as strong. As I been researching on here I curious what voltage should my Baro sensor read. With my test light when i test my sensors it lights bright but when I test the Baro sensor its very dim so I wondered if this was suppose to read lower. Also if the engine was bad (low compression) wouldn't it throw a misfire code and flashing cell when the car is on. I dont have either.

Loki

iTrader: (1)

Some low compression engines run fine without symptoms. The right way is to have the compression tested with a tester. The baro sensor is sooooo far from the first thing you should be concerned with, it`s not even on the same continent. The main things to check are compression, ignition coil and spark plug health, catalytic converter.

Thump

Thanks for your reply I have put new coils plugs and wires already installed. all coils have been tested. i will be doing a compression test this weekend when im off work and there is not Catalytic converter but test pipe in replacement of it. From what i read if the compression is going bad would'nt i have hard hot start issues?

RX8Soldier

iTrader: (24)

Hot starts aren't always a symptom of low compression. You need to verify with a rotary specific compression tester.

mazdaverx7

iTrader: (6)

When you say its not as strong as it should be, what do you mean by that statement? Is the car not as fast as you had anticipated? Is it running rough or having trouble starting? You're on the right track with plugs, wires, and coil replacement. Have you checked the air filter? A clogged air filter is not only a restriction but it can cause the mass airflow sensor to have goofy readings. I also would not be concerned with a barometric pressure sensor as a potential failure point.

Thump

No i can definitely tell there is some power loss is sluggish up to about 4k when the car runs i smell fuel very stongly (i assume it from the test pipe) I took the maf off and cleaned it up and reinstalled it. I know the two inner rings were removed from the tube but i dont know if that makes a prob and also there was some evidence of oil in the tubing but i clean that out as well. enough oil to make it down to the actual air filter. I read about over filling the car with oil but i dont know if thats the cause of it or not but oil def made it to the filter. The codes i get when i install the scanner is p0107 p0171 p0037 and u0121.
Thanks again for all your replies. I am not heading into work!

TC4Tay

P0107 is probably showing up because of a possible vaccum leak. P0037 is there if you have a test pip and no cat. As for the ABS code, that might take some more diagnosis to figure out.

Thump

yea i fig the test pipe would throw the code and the abs if from one of the wheel sensor from what ive read i will recheck all the hoses again to see if that's t he cause of my problem. How important are the alternators on these vehicles i mean i know an alternator is vital but i notice once the car heat up and i turn the ac on the car shuts off completely. but if i just start the car or if the vehicle is cold and i turn on the ac on its fine. i wondered if it was the alternator cause when i hook up my reader to it the voltage drops down to around 12v. But what confuses me is if its the alternator wouldn't it drop regardless of the car being just started or not or warm or not?

gwilliams6

Engine Power Loss
• chokes as revs increase
o O2 sensor failure (too rich)
o MAF failure
o MAF disconnected
o e-shaft sensor fouled
o accessory belt fraying
• high end power loss (hard fuel cut)
o Rev limit reached
• high end power loss (jerky and stumbling)
o Ignition failure
o fuel pressure loss
o e-shaft sensor fouled
• high end power loss (smooth)
o Catalytic converter clog
o air filter clog
• low end power loss (smooth)
o Engine compression loss
• low end power loss (stumbles)
o Ignition failure
o front O2 sensor failure
• revs slowly but smoothly
o O2 sensor failure (too lean)
o catalytic converter clog
o air filter clog
• sudden power drop at a specific rpm
o Intake valving actuation problem
• trouble getting to redline
o Ignition failure
o front O2 sensor failure
o catalytic converter clog
o air filter clog
o e-shaft sensor fouled
o fuel pressure loss
o MAF failure

gwilliams6

RX8 Club’s recommended maintenance schedule, more comprehensive and proactive than Mazda’s schedule.
30,000 miles:
- Replace Ignition coils
- Replace Plug wires
- Replace Spark plugs
- Clean MAF (mass air flow sensor)
- Clean ESS (e-shaft sensor)
- Reset ESS profile
- Clean power steering connections
- Clean battery terminals and clamps
- Replace transmission fluid
- Replace coolant (Mazda FL-22 is highly recommended)
- Replace air filter
- Replace brake fluid (fluid in the brake lines AND the clutch line)
~$300 USD in parts if you shop smartly.


every 60,000:
...all 30,000, plus...
- Clean all chassis electrical grounding points
- Replace accessory belts
- Clean OMP lines
- Replace rear differential fluid
- Replace thermostat
- Clean / Straighten AC condenser fins
- Clean / Straighten oil cooler fins
- Inspect catalytic converter
- Clean / Inspect intake valving
- Consider / inspect all points in 90,000+ as well, many items fail early
~$130 USD in parts if you shop smartly.

90,000:
...all 30,000, plus any 60,000 not yet done, plus...
- Replace coolant bottle
- Replace radiator hoses
- Replace radiator
- Replace front O2 sensor
- Replace motor mounts
- Inspect clutch pedal assembly for flex / weld breaks
~$900 USD in parts if you shop smartly.
At 100k, anything original in the cooling system is really suspect and failure prone. It represents the biggest threat to your engine.
__________________

Thump

i will check the compression for sure this Saturday. From reading that list that is my only option left other than rechecking all my hoses which i have pulled up the diagram. So you believe the alternator isn't a main concern for my issue right now. Thanks

gwilliams6

Code P0107 is Baro sensor circuit low input ON 1 CCM

Code P0171 is System too lean ON 2 fuel system

Code P0037 is Rear HO2S heater control circuit low ON 2 HO2S heater

Code U0121 is Communication error to ABS HU/CM

Thump

yes i have a reader thanks i know what the codes mean but i was determining the reasons those codes are thrown maybe i need a new baro and o2 sensor

Loki

iTrader: (1)

What fuel trims do you see? A lean condition shouldn't really happen unless you're ingesting a ton of unmetered air. Make sure all the little intake hoses are snug and there no loose openings.

The two "rings" you refer to, do you mean the screens before the MAF? You need those, they help the MAF read correct airflow especially at low rpm.

For the rear O2 sensor, is it even installed into the test pipe? Check that the wiring is not damaged. It's not impossible that you need a new one, but wiring is easy to check, and it can be damaged if someone had taken the transmission out.

Thump

i will check my fuel trim and post it yes the original intake tube was tampered with and that is what i meant by the two rings the screens i have an additional stock intake i can put my hands on though. also yes the rear o2 sensor it installed onto the test pipe but i will double check the wires again more thoroughly

Thump

alright guys i check the compression on both and this is the results on no. 2 the leading and trailing read 80 psi and on no. 1 the compression didnt even read 10 so i guess this is my answer no 1 is shot. I did not use a mazda specific compression tester just my original one. So my next question is would you say the motor is worth rebuilding,swapping another rotary or a motor swap all together. I bought the car for a steal and knew what i was getting into before.

mazdaverx7

iTrader: (6)

Depends on how clean the car is. If its a clean rust free no wrecks car then absolutely its worth it. If its not so clean but you love the car then it is of course worth it! I'm in the process of saving an 04 GT that has rust and has been neglected for years. Saving it because its still worth saving to me. I like the car, therefore I'll save it where others would most certainly part it out.

gwilliams6

If you bought the car for a steal and it is otherwise in good shape, by all means just get the engine rebuilt. Don't know where you live, but here are some recommended rotary specialists that do quality rebuilds. There may be other good ones near you. At least this will give you an idea of costs. Much will depend on the condition of any possible reusable irons and such, once the engine is opened up and examined.

Black Halo Racing
RX-7 & RX-8 Performance (Pettit Racing)
Pineapple Racing
Racing Beat - Mazda Performance Specialists
Rotary Performance
Rotary Resurrection

Thump

i paid 700 for the car and i have another guy that wants to sell me his for 500 but the motor is in the same condition and i am located in tennessee

mazdaverx7

iTrader: (6)

Kevin Landers is In TN and he is a very reputable rotary builder.

Thump

thanks