Woolfie

This might take a bit of explaining but I'll try to keep it short...

The car suddenly lost power recently on the way home and basically felt like limp mode but I was so near home I kept it going (yeh I know). There's a short hill on the way which brought me down to first gear and 10mph and at the end of this I looked in the mirror as the car spat a few red hot chunks (bits of cat I'm assuming) out on the road!

Turning in the drive I got out to find not only a red glowing cat but red hot tailpipes too!
Assuming a choked cat I've since gutted it (most of it was melted indeed) but this hasn't made a blind bit of difference.

The car will still start but hardly takes throttle, is slow to rev, only runs reasonably smoothly at around 4000rpm and will hardly idle at all running very lumpy.

The code is p0106 which is manifold absolute pressure/barometric pressure range/performance problem.

I've tried another bps and maf with no difference. Tried a new crankshaft position sensor and the car wouldn't start at all, waiting on delivery of a second hand throttle body as I write this but I've noticed the current throttle body doesn't open until the pedal is half down and goes to fully open by about three quarters down??

The car is an '04 and has been running on premix and a cutback exhaust without any problems for well over an year now.

Any help would be most appreciated!!

Woolfie

sonicsdaman

iTrader: (3)

since you are new here I'm going to assume you know very little about the rx8 and rotarys in general so read the newbie thread and then read it about 10 more time
New & potential owners start here

Woolfie

New to the forum yes, new to RX8 ownership and it's ins and outs no. But thanks for making me look stupid anyway.

sonicsdaman

iTrader: (3)

No one made anyone look stupid. That was you're first ever post, how am I to know what you may or may not know

let's start with you giving us as much info as possible, miles on current engine, trans type, mods, how much fuel was in the tank, etc. ( it's hard enough to diagnose a car on the interwebz)
the fact that the exhaust was glowing red is bad, the engine is running extremely hot. Like you said a clogged cat which if left go for a long time will cause problems including engine

Woolfie

Sorry, I shouldn't have said that especially as a newbie here. I guess this car's just trying my patience a bit today!

It's a 231 manual trans with approx 50k miles on it. 45k when I bought it and I replaced the coils (latest mazda type), leads, plugs and starter right away to ensure I got it off to a good start and kept it healthy. I've never tested the compression but it's always been a good starting car hot or cold.

Only other mods were as I stated - the catback exhaust and approx 200ml of two stroke oil every fill of the tank. I had filled the car up about two minutes before this happened.

Incidentally this happened at the same time as I momentarily lifted my foot off the throttle and put it back on again.
Although the exhaust was hot the temperature gauge was fine and the oil pressure was and still is fine.

I'm particularly wondering about the throttle body - surely it should open smoothly from closed to fully open in line with the pedal movement?

From what I've read the fault code could also be thrown up from a leak in the intake side but I've checked for leaks and split hoses/tubes and there is nothing obvious.

sonicsdaman

iTrader: (3)

It's cool we've all been there and sometimes the internet in a unforgiving place(bring a flame suit).

Based on the way you called it a 231 manual leads me to believe you are not within the USA( no problems with that ).
Now the new ignition set up and updated(faster) starter "masks" hot and cold start issues. One can not truly say that their engine is "healthy" without a compression check(maybe to late). When it gets done you should get a minimum of 7-8 numbers, compression on all three rotor faces(x2), and the cranking rpms. More on this in the newbie thread.

This could be important, the 8's have an issue with the fuel pump when below 1/4 tank and turning. This will cause fuel starvation to the pump making it get weaker which is bad ( I tend to not let it get lower than 1/4 tank).

Depending on the premix (most are safe for cats) it could shorten the life of the cat on the car, the number one recommend mod is to get a high flow or remove it( this is illegal for road usage tho and hard for emission strict places). Once again it's probably safe to say your cat is dead anyway.

This seconds my, believe you should inspect your fuel pump.
The temp gauge on the dashboard is what's known as a "dummy" gauge the needle will not move past normal operating position until well beyond the point damage is probable ( if the needle moved you're way past 220f).

The TB is controlled (fly by wire) electronically, make sure the battery terminals are properly seated and no grounding issues.

The easiest and fastest way to find a leak is with a pressure or smoke test.

Woolfie

Thanks for the help, yes I'm in the UK. Orkney in Scotland to be precise and hundreds of miles and a stretch of water away from the nearest Mazda dealer for a compression test lol.

I'll hopefully get the throttle body to swap out tomorrow and I'll give that a try, I'm suspecting that the unusual opening movement is to blame and might throw that code as it'll work in line with the maf and bps. I had never considered the fuel pump though tbh, it'll be the next thing to try if I don't get any joy with the throttle body swap.

sonicsdaman

iTrader: (3)

check out the local section to see if there are any rotary shops around you might get luckey.
a quick and dirty check on the engine condition might not hurt either. Pull the sparks and have someone slowly spin the engine from the pulleys while you look in the spark plug hole

Woolfie

Well, my worst fears were confirmed, the DTC was just a bizarre distraction from the real issue.

The apex seals are indeed f**ked. Shame cos I really loved that car

I'll need to look at my options now but it isn't worth an expensive rebuild, breaking for spares looks like the best way to recover some cash out of it.

I'd still have another one though, I'd love an R3.

Tip for the future: no jerky throttle movements...

sonicsdaman

iTrader: (3)

That's some shitty luck however this is why we tell everyone to never buy a rotary powered car without a rotary specific compression check(gives a better idea on engine life/health).
Like I said yesterday check the local forums/threads and google, to try your luck for a rebuilder. I've heard of some builders here shipping across the pond but shipping is probably expensive

04Green

iTrader: (1)

Sorry man.

I caught mine before it died, but still spent a bit on the motor ($7K US) for a Pettit motor. What a freaking difference. I share that for a few reasons, when the car was rear ended, I kept the motor for the next one. With a motor, you can get a really cheap 8. I ended up buying a car from Pettit, with a new motor in it, and sold the old one to swoope. I think he really likes it. The story is, if you really like the 8, get a good motor, then change the bodies as they wear out. If I had not found the blue one, that plan would be going strong.

Just a thought.

Woolfie

That's certainly worth considering indeed

It's just a pity you can't inspect the walls of the housings without actually dismantling the engine (like inspecting a two stroke cylinder through the exhaust port for example).

If it was just a case of buying new apex seals (REALLY optimistic I know) I would rebuild it myself but if it needs new housings then it's really not economically viable for me just now.

Woolfie

I do have one of those bendy endoscope cameras that plug into a USB though, but the end diameter is slightly too big to fit in a spark plug hole. Anybody know if this would fit through the intake or exhaust port into the chamber?