Rhys19

So about maybe almost a year ago, since I got this rx8, it was sitting for around 5 years did the process to get the oil injected but not starting the engine for a bit, changed oil, etc and when I actually got it running I noticed on a couple of test drives it overheated on days of around 80*F, I have read that the temp gauge is basically a dummy gauge it only moves after it's too late!

my real question is here how the actual heck is my coolant seal not blown???

I was afraid because people usually say after it overheats it's gone, but no coolant level has dropped, the engine hasn't flooded with coolant, it doesn't really smoke, (Smoke def doesn't smell like coolant), etc yet it still runs almost perfect???

A few other issues with it are
It misfires only around 7-8K
my fuel economy is really really really bad! less than 80 miles per tank whether I highway drive or not.
Long term fuel trim says 22,
AFR is around 14 sometimes 15/16
O2 sensor 1 voltage says: No Data Found???
O2 Sensor 2 Voltage: 0.1,0.3
I'm guessing the front o2 is shot for my fuel
as for the misfire I've replaced coils, plugs & wires, however the coils were on the cheap end, I'm thinking of ordering either the LS coils or just get BHR coils not sure yet.

but I am genuinely questioning why haven't I got a blown coolant seal?

Also the overheating my second radiator fan connector was busted so I soldered them on.

I am new to rx8's however I know a small amount like change your oil, premix, always use 93, etc so any tips would be helpful!

dannobre

iTrader: (3)

Sounds like the fans might have not been working properly. Might want to check the thermostat as well...

Overheating is relative. A few degrees makes a big difference in how things end up

Sounds like you were lucky 🙂

No functioning O2 sensor will make it run really rich.. and it looks like you probably have a vac leak of some sort with the fuel trim that high even with the car likely not running in closed loop.

Left4Dead

Welcome

Really hard to answer your main question of how did you not blow a coolant seal. I suppose there are many factors to is my engine healthy, Compression test being the most relevant test you could perform to know your engine health.
You could check the wiring for your o2 sensor
As for coils on an rx8 you really do not want to go cheap it is just not worth it get either Mazda OE coils or BHR type upgrade.
Cheapest way to moniter actual coolant temp is with a bluetooth obd guage connected to a free app on your device of choice.

Also lots of amazing information can be found here
https://www.rx8club.com/new-member-f...t-here-202454/

Rhys19

Overheating was fixed, one of the fan connectors was busted so I soldered it, and yeah I guess I'm lucky I just don't understand because the first time I noticed was it was already at the last few marks before H, I will be getting a compression test here soon, as for the o2 sensor I'm not sure I checked the o2s1 voltage and it shows data not found, I checked wires & they seem good and the engine side of the connector one pin outputs 12v and one of the other pins puts out 9v, as for vacuum leaks I've tried brake cleaning all vacuum lines I could find, but the engine never revs up it stays a constant idle, I've cleaned the MAF, I know the rear o2 sensor is bad the wires are frayed to almost broken off on the cat sensor and it's throwing a bank 1 sensor 2 code ho2s.

I'm leaning towards the front o2 sensor to be honest, I will see about getting the intake some tested for vacuum leaks but i'm not sure.

as for my misfire could my ssv not be actuating I notice sometimes when driving very rarely I will feel the car rpm's like drop a bit but then go back up, is that the ssv/vdi opening?
I have replaced plugs, wires, and coils like I said before coils are on the cheap end, probably the first mistake lol, I was thinking of getting either BHR, or just use the LS GM coils (with mounting kit and wire conversion kit)

Rhys19

I am honestly surprised on that one, like my gauge was towards the H, yet it barely smokes (only on startup then goes away after it's warmed up), no coolant loss, engine starts almost instantly, etc Although I think the o2 sensor is bad, wires are fine, and I have been constantly monitoring coolant levels with an obd2 reader, ever since I fixed the fan not really overheating although I hot days I notice the temp gauge tick up one & then drop down after a few seconds, I checked the second fan and it seems the bearings are going out, it spins hard while the other spins freely.

Also as for your coils comment so BHR or OEM, some people have mentioned using LS coils like here: would LS be worth it or just stick with oem or bhr?

Loki

iTrader: (1)

The front 02 sensor is a wideband, it's impedance based, not voltage. So not seeing a voltage via OBD is normal.
Misfiring at high rpm is usually a clogged cat. So you'll want to confirm that's not the case before driving any more.
BHR (Black Halo Racing) makes a great plug and play LS coil based kit.

As for how come your water jacket wasn't breached, who knows. A lot depends on how quickly it overheated.

Rhys19

Alright, thanks for clarifying the o2 sensor voltage situation would it hurt anything to just buy one and slap it in? I know it's $200+ but would it be reasonable given the fuel trims are that high at 22?

as for the clogged cat I've looked at it, seems good, ran cataclean even, but after a hard drive my o2 sensor is also not blazing red glowing hot.

also any idea behind this screeching noise at 2k only at the 2k line not 1.9K not 2.1K
Video still uploading I think.

Rhys19

So I found a loose plug wire, fixed it by opening up the connector and the misfire kinda went away, it's still visible between 2nd gear.

Also forgot to mention I figured it's probably important

Car: 2004 Mazda RX8 - Engine was replaced but the previous owner put in an 06 engine, it has 4 oil injectors (Not sure if it's important or not) but also idk how to tell how many ports it is, from what I heard 04-05 is 4 port and 06-09 is a 6 port?

Mods done:
Almost none it's like bone stock except for the coils & plug wires (Plug wires are ngk)
Though I did have to replace my fuel pump.

Also I have an evap large leak & small leak code, had it smoke tested but no smoke coming from anything, replaced purge valve, charcoal canister, the only other thing I can think of is Leak Detection Pump (LDP).

Loki

iTrader: (1)

Your fuel trims are high because there's a vacuum leak. O2 sensors don't read high or low, they read erratic or not at all when they break. Put that $200 somewhere else

A 6-port will have the extra 2 runners on the lower intake manifold. If it's an automatic then yes, 04-05 will be 4-port and after is 6-port with a lower redline. If it's a manual and you're in north America, it's a 6-port.

rx8help.com might be useful to catch you up rx8 ownership.

Rhys19

What are some other ways to check for vacuum leak? Smoke test the intake? I already tried spraying all the hoses with carb cleaner, I went through like 5 cans and the engine didn't rev up, sprayed around the UIM seals also.

What about the rear o2 sensor, I have 2 year plates already so should I worry about it at a later date? (They still emission test here)

also I think my cv axles are bad there's a bad vibe in the rear, I looked up the axles and I can only find the driver side, does that fit both? (My axle boots are also ripped and there's like no grease left in them tried replacing the boots but no change in the vibration)

EDIT: Wanted to add, after driving today, my misfire is like totally gone after fixing that plug wire! I still am going to get the coils though. might go for the bhr coils

Rhys19

Oh Ok, this is odd, before when testing if my maf was working the engine would stall, my battery light came on when I started my car earlier so I checked my battery it's holding at around 14.5V so I unplugged the maf to see, and the engine never stalled and my afr is like way out of range around 18, 19 and hits 20 sometimes (While idling) does this mean my MAF is bad? It's been cleaned already, made sure the connecter was on there, the connector no longer clicks so I made sure it was hella tight, and the pins aren't corroded or anything

Loki

iTrader: (1)

Um. Let's slow down. Plug your MAF back in, the car needs to know how much air it's getting. It runs very lean because without the MAF it's guessing at the air it has based on rpm and throttle position. It's a failsafe, not intended long term operation. Nothing in this story indicates the MAF is bad.

There is a nipple on the underside of the UIM near the throttle for the VFAD, which is invisible from the top and can be the source of your leak. You also mentioned an Evap leak, track that down.
Smoke doesn't always work for small or out of sight leaks.

There's no point in measuring your battery voltage while the car is running, all you're measuring is the alternator output voltage.

Leave the rear O2 sensor alone, it has even less to do with your symptoms. Honestly it sounds like all you have here is a vacuum leak, and the ignition wire you fixed. Track it down and you might be fine. In addition to an open hose, it's possible yout hoses are misrouted after the engine replacement. Make sure it's all connected properly. One other sometimes problem area is the vacuum accumulator box under the UIM. It has one hose from the intake going into it, and I think 3 hoses going out. If it's cracked, there's your problem.

Is the intake original?

The axle boots are a problem, if not today, then soon. They won't get better on their own

Rhys19

Oh no I didn't leave it unplugged, I just noticed the battery light so I tested a few things by unplugging the maf & plugging back in, the car never changes in tone or RPM.

As for the vacuum leak, I'm guessing the vacuum box is where those solenoids are, I've replaced them before but I essentially took the UIM off, could it be that I need to order replacement UIM Seals?

Also that nipple you mentioned... is it the one with the hose connected to it with a green check valve looking thing? that's connected it looks like to this black box which I think you refer to as the Vacuum Accumulator, I can order some intake seals if I need them, and then take the UIM Off and inspect it along with the hoses & that black box.

And my battery should be good it was bought early this year, I tested it also with the car off, 12.92V and drops only to around 12.85 and then it stops dropping.

Battery was tested at O'Reilly's and they said it's good.

also another fact not sure if this will help me tell if I have a vacuum leak: In my Torque App there's a vacuum gauge in there, it says -16 INHG - -18 INHG is that too low?

Right now I'm looking to troubleshoot versus buying random parts and just throwing it on hoping it fixes it, There's a reason I mention alot of things.

Also, I've had the evap leak checked, by multiple shops... They keep saying no evap leak, Gas cap was replaced and they even replaced the evap lines, but it still says there's a leak, which is what typically lead me to the Leak Detection Pump, if it's bad then wouldn't it throw a leak since it can't check the Pressures?

I'm not sure of anything else wrong with the car tbh, it's just shitty fuel mileage like worse way worse, I can't even get 90 Miles to the tank even if I drive it like a normal driver & not drive the **** out of it.
and highway miles are a bit better but I still only get maybe 89 out of it highway.

EDIT: Your asking if the intake is original also, If you mean like the intake from the outside air to throttle body yes bone stock, it's got that giant black box for one single air filter
I never removed it because A: I heard mazda makes those pretty much tuned from factory, and B: I'd like to keep some stock parts.

Also, Should I replace the axel boots? or just replace the axels? It worries me that there's a big vibe in the rear and the boots are torn... there's a universal boot I can buy from o'reily's or it looks like some OEM boots from ebay? looks like for the oem boots I have to take the axel out of the wheel hub.

Loki

iTrader: (1)

You don't need new UIM seals if the current ones aren't damaged. But yes, if you had the UIM off, it's possible it didn't close snugly all around. Worth checking.

16-18mm of vacuum sounds ok. Really depends under what conditions.

What is the leak detection pump? I'm not supe familiar with the evap system but I've never of such a thing. The ECU has selftests for most of the sensors that have come up so far, so when it sets a code it's pretty good indication that it has found that specific problem (not always but its a good start). It's also indication of what problems it didn't find, by what codes were not set. What codes are currently set for you?

Have you already had the cat checked?

Rhys19

I'd have to recheck but I do have system bank 1 too lean (Always set), HO2S heater circuit something, and evap small leak & evap large leak

The leak detection pump also known as a fuel tank pressure sensor, (Though it doesn't seem to sit or go between fuel lines only evap lines) just monitors the pressures of the EVAP system as far as I could research
the leak detection pump for the rx8 looks exactly like this: https://www.ebay.com/itm/353916502847 I believe it's above the rear subframe near the EVAP Charcoal Canister, I saw it when replacing the canister.
the LDP runs around $80-$100, I will check the UIM again, it looks sealed although the previous owner seems to of not had 2 of the throttle body bolts??? also the UIM is cracked on the second bolt where the oil filler tube connects to the engine block.

also I believe I found the LDP on a genuine mazda dealer site? https://www.mazdaparts.org/mazda-lea...tion-pump.html idk if it's a real genuine site but it looks like it.

Also, I am scheduling a compression test for a couple of weeks from now (mainly because we're getting blizzard weather from the 22-25th) So then I will know whether it's feasible to even continue working on the car or if I should just get a new engine/rebuild.
If it comes to a rebuild/new engine based on my engine issues should I go for a rebuild & just buy everything else that would go with it, or buy a new engine? I've seen some engines around 6K

I'm also not sure what conditions I would monitor for the vacuum like while driving, etc? and what levels would I be looking for, like solid 16-18? or something higher or lower?
As for the intake seals they don't look cut, however they do look really smashed the last I took it off.

Loki

iTrader: (1)

If you have bolts missing at the throttle body and a crack in the UIM, let's sort that out before worrying about vacuum. That's exactly the kind of stuff that gives you unmetered air. The intake needs to be airtight after the MAF all the way to the rotors. If the seals are smashed, then yes you'll want to replace them.

If it comes to it, do not rebuild your engine. Get a known good rebuilt one from a rebuilder or Mazda. Yes they're not cheap. But what's even less cheap is rebuilding with worn out and heat compromised parts.

If you can get the actual codes it would be helpful but- system too lean - consistent with having a vacuum leak and getting too much air in- O2 heater circuit: now this is a failed oxygen sensor. Not the sensing element itself but the heater which gets it up to temp. Make sure the wire to the sensor is OK, and replace the sensor. Figure out which sensor it's talking about. Sometimes when reinstalling the engine it's possible to pinch the rear O2 wire against the firewall.

Evap stuff: could be related to the vacuum leak if someone misrouted the vacuum lines that touch both.

Don't monitor vacuum, there's no useful info there. You're not boosting so manifold pressure will never get interesting.
-

What about the cat?

Rhys19

Alright, Well I went ahead and ordered new throttle body bolts they had them on Atkins rotary, and thanks for the tip if it comes to a rebuild, I should know more after the compression test, let me see I have
- P0037 - HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
- P0171 - System Too Lean (Bank 1)
- P0455 - EVAP Large Leak Detected
- P0442 - EVAP Small Leak Detected (this one is just a guess my evap monitor has not completed yet so the codes haven't showed up)

As for the intake seals the oil filler tube one looks really smashed, the intake ones are debatable, they do look a tad bit smashed the intake seals are around $40 on atkins rotary.

Also I just found out my battery light, when I was putting the UIM back on after inspecting it (No cracks checked) it pulled one of the alternator wires out of the connector, so I repinned it and now it's gone.

As for the UIM Inspection Resulted in something I was suprised:
- No Cracks
- the suprising one: One of the solenoids on the Vacuum accumulator was missing that tiny seal! luckily I had spares when trying to find the one that the purge valve sits in (The edge of the purge valve seal is cracked I'll get a pic if I can find it I had it saved) so I replaced that.

anyways put the UIM back on, alternator fixed, and my vacuum went from -16 to a pretty solid -18 but also noticed when the engine revs up the vacuum turns into boost, while you said this is not relevant since there's no boosting manifold pressure, but figured I'd share it anyways.

Also one thing that suprised me
I found a reman tag! on the motor! right beside the alternator, it's a big blue tag that says remanufactured idk if that means anything other than it might be a remanned motor instead of one from a junkyard that could've been an original but who knows.

So anyways IF you think I should go ahead and order the intake seals will do, taking the UIM off is pretty much easy to me now since I've done it a few times already. that one bolt between the firewall & the UIM is a pain in **** to get!!! but nothing a u-joint can't get!

Loki

iTrader: (1)

The reman tag makes it a reman. Is it dated? That doesn't mean jt didn't also come from a junkyard later in its life though.

Yes if the seals look bad, I would replace them.

Higher vacuum is good, as long as it's at the same rpm. The thing you want to monitor is short term and long term trim, and MAF airflow (g/sec). While driving they will jump around, so you don't need to watch them closely, but what you want is that your fuel trims are near 0 and MAF rate is around 5g/sec when idling around 800rpm stationary and fully warmed up.

Rhys19

Yeah I figured it could've still came from a junkyard, I'd have to take a closer look, it's pretty deep like right next to the coils anyways as for the data:
MAF is around 5G's when idling around 800 RPM's, as for fuel trims it looks like my Long term says 22, short term is like maybe 5, I'd have to check.
the long term seems to stay around 22 even when driving, redlining, etc so Not sure about that one it does say Long term, but short term kinda bounces but not really, driving normally it'll bounce between 8-18.

My car is warmed up when checking these results, and no I don't drive it until it's warmed up. I don't go by the Gauge in the cluster I usually start driving when OBD says temps are around 190-205*F

Loki

iTrader: (1)

You can drive earlier, just don't beat it on it until it's well warm. In fact it's not great for it to idle for a long time, that builds up carbon over time. If it's the dead of canadian winter, you can wait till the needle starts moving, but beyond that it's fine.

5g @800 is a good sign. Maybe your work today closed some of the leaks and the long-term value will come down over the next drive. The way trims work is long-term is % additional fuel over the base fuel map, and short-term is a % on top of that (collectively up to a max of +/-25%).

Rhys19

Ah gotcha, I do have an automatic trans, I typically do the usual redline a day though, you can ONLY do it in manual mode and usually only in 1st or 2nd gear.

EDIT: When I had the UIM I did notice there are 4 oil injectors? I thought 06 only had 3.

Loki

iTrader: (1)

No RX8 only has 3 injectors.

Rhys19

Hm, interesting I wonder what the other one was? or maybe there was 3 and I just wasn't looking clearly, I'll check when I get the intake seals!

Loki

iTrader: (1)

I think you misread. No RX8 ever has had 3 injectors. It's 4 for series 1 and 6 for series 2s.

Rhys19

? You just said that the rx8's only had 3???

"No RX8 only has 3 injectors."

although if it is an 06, then i Might have only have spotted the 4. I wasn't really paying attention was more focused on getting the intake back on.