In my experience, if a t-stat fails closed if the engine has had a previous episode of serious overheating. That cooks the wax and the valve doesn't open. That's why it's not common...at least in my experience. It's also why it's convenient that they're cheap/inexpensive. Whenever an engine seriously overheats the t-stat should be changed out.

 

Hi everyone,

Quick ecu question. I'm looking to buy an rx8 as a fun weekend car, and most of the ones for sale are 04 models. I noticed the 04 came with a 16 bit ecu vs the 32 bit in following years. My question is, how big of a deal is that? I've searched but can't find much info on how much it matters..?

 

That's a good idea - those things are cheaply made. Can't vouch for prior history on a couple of closed failures in friends cars, but most of the overhearings I've had (at least the last two, maybe 10 years and 35 years ago - cars I bought new and knew their full history) the only overheating event ever was from the thermostat. I remember the last one was physically broken - something like one of the pivot points had snapped.

Maybe we should start a poll on thermostat failure modes.

Ken

 

What controls the oxygen sensor readiness monitor?

Also if my upstream O2 is reading proper AFR, but the above monitor will not become active then could this sensor be faulty? Assuming that this sensor controls this monitor.

If not and the downstream O2 controls this monitor, I assume a masked P0420 will cause this monitor not to become active, but why would my catalyst monitor become active when it is controlled by the downstream O2.

 

Masking the CEL doesn't give the ECU the correct info it is looking for to set the monitor.
It needs the precise readings it expects and the fact the CEL pops up in the first place means it isn't getting it

If you are looking to pass emissions you may be OK..depending where you live they often are ok with no CEL and only some of the monitors set

 

Thats contradictory,

I have P0420 masked, but my catalyst monitor is active and ready.

I can get every monitor ready except oxygen sensor, but I may have to get rid of my secondary air system which means now that monitor will fail. NY inspection only allows 1 monitor, so with 2 I will fail. So I need to find out why oxygen sensor is not become active.

From on online source
O2 (Oxygen) Sensor:
The O2 Sensor Monitor watches for the performance of the vehicle’s oxygen sensors. Oxygen sensors are used to fine tune the amount of fuel that is used by the engine. These adjustments are made several times a second and have a direct impact on fuel economy and emissions reductions. When an oxygen sensor goes bad, the vehicle will usually begin to use more fuel than it needs to, thereby increasing the amount of harmful emission

Catalyst
(also known as catalytic converter): This monitor uses the readings from oxygen sensors located before and after the catalyst(s) to determine the efficiency of the catalyst


So my catalyst will become active using both 02 even with a masked CEL, but my oxygen sensor monitor will not become active which by the looks of it uses the downstream o2, yet I get good AFR readings from that sensor.

 

It takes a while to set that one. Do you have a FSM...there is a drive cycle in it that helps to set the monitor.


I think I posted it a while back someplace

 

My car overheated a few months back! The damn rubber grommet under the air filter fell into the fan So you think my t stat is damaged because of that? Thing is, it didn't really get "stuck". I was stuck in traffic. My temp slowly creeped up to 221F. It took about 3 mins to get up there. Turned on the heater and it went down fast. Turned on the AC again after it went down and kept driving for 30 mins more. Never happened again. Drove back home for like an hour. Nothing happened!

My traffic temps are usually around 210-215F. It fluctuates. Whenever I start doing around 20mph or more, it drops down to around 205F. If I'm just sitting in traffic, temps will slowly drop to around 200F. Slow moving (less than 10mph) makes my temp go up to 215F. I have never seen it go above 215F. That was the first.

Can a t stat, on some occasions, take more time to open? And then on other occasions, work perfectly?

 

I have 22 active drive cycles completed, and 421 miles since DTC's reset last. Should be sufficient.

 

Hi guys ... A lose friend of mine is a manager And head engineer at a metal fab. Shop ... I'm trying to find some good pictures of what the OEM crash bars looks like and maybe some pics. Of a few nice. Custom crash bars. However I'm haveing trouble finding any even with Google. Can somebody send me some links with some good pictures for us ? Would b greatful thanks

 

Don't you own the car? Just pull off your bumper and look, you can even get measurements and things. It's not like it's hidden away, it's the massive crash bar looking thing.

 

They open at a particular temperature, so opening/closing time would depend on what the engine and ambient conditions are up to.

But if you're getting erratic behavior, replace it. They can get screwy when failing.

Ken

 

^I could see suspended debris and corrosion and/or neglected acidic coolant affecting how smoothly a t-stat operates.

 

My car suffered from an overheat 6 months ago. Car seems to be fine. Mines a 2007 and came with FL-22 coolant. I have never changed it. I did however loose a bit of coolant when it overheated. I topped it off with some Caltex green coolant. I didn't mix it with distilled water. I thought it was pre diluted. Could that be the reason why my car's temp is a little high?

It spends most of its time at 212F when driving around in town. Whenever I step on it gently, it hits 215F. When it hits 215 I just cruise and it drops back down.

I was coming home the other day on the freeway and I floored it from like 25mph until I hit 93mph, and the temp went up to 219F :O I then slowly cruised to a halt and it went down to 212. That freaked me out. Is that normal?

 

Coolant is your secondary method of cooling. Anything over 200 at cruising is outside normal. Sounds like your not getting enough airflow across the radiator. Stopping 212 is normal.

Your primary means is oil, combustion, and heat indexing/exchanging of the block materials. Make sure you using good oil and not synthetic, and that it is there obviously because the car burns it off. Some premix won't hurt either if your being mean to the car.

 

Please - forgive my ignorance. I have a 2005 Black Cherry Shinka 5-speed that I sort of 'inherited'. We are NOT mechanics...but i do LOVE this car.

The dealer told us we needed new rear brakes, and the quote was absolutely out of this world for the work. Hubby, bless his heart, thought he would tackle the job himself. He got the left rear wheel off, realized he didn't have the right tools, and put the whole thing back together.

Now when I hit 38mph, the back end starts to make a rhythmic noise and I can tell something isn't right. What could he have done??

 

did he torque the lugs? did he remove anything else besides the wheel?

 

When he torqued the lug nuts, did he work around in a star pattern, tightening them evenly?

If he wants to tackle it again, there's a DIY:

https://www.rx8club.com/series-i-do-...e-pads-172382/

The only "special" tool needed is the little cube-like thing for rotating the caliper piston back in place. The rest is pretty ordinary. And there's a whole community here on standby to answer questions.

Ken

 

I'm using Mobil Super 1000 10W30. Changed 1200 miles ago. It's been a year now. Should I wait until I've done 3000 miles or change it now?

I forgot to mention that my ambient temps are around 90 degrees. I will seal around my radiator and see. Could this be a water pump issue?

 

I need help interpreting these Mazda dealer compression test results. Ive searched the thread and various other websites and cant seem to find a source that normalizes my numbers to 325 rpm

My results;

Compression test results after engine decarbonization:

Rotor 1 @325rpm: apex 1: 7.1, apex2: 7.0, apex3: 7.4

Rotor 2 @326rpm: apex1: 6.9, apex2: 7.2, apex3: 6.8

Values x100 kPa

according to the dealer "Minimum spec is 5.0"


I dont know enough about compression tests to understand these results. I do know that rpm testing ranges vary based on starter motors and sea level and what not.

 

New and Potential Owner's Start Here: I got my compression test. What do these numbers mean?

Yeah, 325rpm is high, one of the highest starter speeds i've ever seen. The chart I made stops at 320, but it's close enough.

Alternatively, in that post i've got a link to an online calculator that you can punch in the numbers for yourself.

If those values are actually...
710, 700, 740
690, 720, 680
then just note them as KPA.

Usually though a number that is 1 decimal precision between 5.0 and 9.0 is either kg/cm2 or BAR (and BAR is rare). KPA/100 and kc/cm2 are close, but don't scale at the same rate.


Either way though, if there are no typoes, then that engine is well past failed. That 6.8 fails the engine if the starter speed was 260rpm (if kg/cm2) or 270rpm (if it's kpa/100)

If you don't have any symptoms of engine failure, then I'd suspect a typo somewhere. If you do, then the numbers are probably right.

 

Thank you for the response. Those numbers are exactly what the dealer has emailed me. The representative explained to me that these were very promising results.
In terms of experiencing any type of compression loss, I used to deal with a 3-4 second start delay. I ran through the check list and changed the battery, coils, plugs, and lastly the starter. I suspect that the starter is powerful enough to mask any sign of low compression. The car idles fluctuates from 790-820, not too rough. I feel as though the tech dealing with my car made a mistake... either that, or im being scammed out of my warranty.

 

Do you know the rough altitude of the testing location? That's the only other factor that could swing the numbers. If that was at sea level, then the dealer fed you a line of BS, that is failing.

 

According to a quick google search, whayne nj is said to be at an average elevation of 375 feet above sea level.

 

according to a google search;

Whayne NJ- It has an average elevation of 375 feet above sea level.