Anybody with rx8 knowledge?

So the local used lot has a 04 rx8 on the lot they want gone, super clean 110k.

Starts no problem when cold, won't start when warm. Wait 15 minutes and fires right up.

Any known issues that could cause this? Possibly coils? CEL is on, didn't have my reader with me will pull codes early this week.

They want 2900 for it, I'm thinking 2k -2500 fix, flip for 4?. Just don't want to get stuck with something needing a motor.

What does the tribe think? Any decent forums out there specific to rx8's that have real knowledge people on it???nto yo bro crowd.

Could be coils, could be bad compression. A compression check will tell for sure.

This forum is probably your best bet. The RX8 specific forums seem to be filled with douchcanoes

Someone will know more, but 110k is definitely danger zone for motor life, especially if it's not running right now. Will a good running one with 110k really sell for $4000?

Yeah so you could try a set of coils and plugs and then a nice decarb but tbh I think you have a motor issue right off the start but definitely compression check after good plugs and coils, fyi last I checked a mazda reman with a good old core is around 2-3k.

4k is not too far off but that would would be with a fresh motor, good luck and any other questions there is plenty of other rotards here.

I had a series 1 with similar miles have the compression come up 20psi with new plugs and coils and a bit of driving. It's some weird voodoo where weak coils means low compression.

I'm not saying that the engine can't also be weak, but if the coils are worn, that certainly isn't helping.

Also, how fast is the starter cranking? For some reason Mazda put a really crappy starter on the engines and after a few years they crank really slowly. If you are familar with how rotaries sound when cranking and this one sounds like it's just dragging along, it needs a starter!

I owned a second gen many moons ago. Quite surprised what a seal kit costs for the motor.Almost worth going right to rebuilt motor if that's the issue.

Lot said its just a Sensor hahaha, the y mentioned the CEL code crank sensor related.

4k shouldn't be a problem with how clean this one is if its running well. However with all this motor talk, I doubt I'll b willing/justify paying 2k for it.

Why would seals work on cold motor and not seal well enough when hot to start?

I have a15 yr old in the house and thinking nice winter project but not looking for something I would upside down in day one this one will need to be well bought.

Offer 1k for it and let them talk you up a bit. I would not go more than $1500. With a motor comes a bunch of other nick nacks that can easily add up to $750 on top of the reman motor. Even at those numbers you are close to being upside-down on it. I would stick firm at 1k.

Not to many more years and these will not require obd2 inspection in my state. When that happens I am going to do a motor swap in one. As it will only require a safety inspection. Make the car that Mazda should have.

That engine is most likely on the verge of failure. I doubt you'll be able to flip it for $4k and make a profit if you spend the money to get it into good running condition.

The only way to be sure is to have Mazda do a compression test. Also have them verify what software version the ECU is running and make sure that the starter is the later revision as well.

I also suggest the starter could be the fix for not starting when hot. Had the same issue with a newly rebuilt engine. Be sure to get the later 2009+ starter as it has more power and spins the engine faster.

Not sure if relevant, but my 13BT was a bear to start when hot until I replaced the injectors with a set that had been cleaned and flow tested. It fixed the hot start problem 100%. Leaky injectors causing hard hot starting is a common problem with older rotaries, and it's worse in an engine with marginal compression.

Hot starts have been an issue with rx8s. Especially early ones. The early cars ('04-'05) have weak coils and starters from the factory. We replaced both on my brother's '05 and it helped immensely. Sure sometimes his car doesn't like hot starts, but it'll catch and turn over eventually if it's being stubborn. Never would have happened with the OEM starter. His car needs new spark plugs every year or so.

Hot start issues on a rotary are a typically an indication of low compression. On the RX8 you have the additional bonus that it may also be the coils, but with that mileage I wouldn't bank on the cheap fix.

If they're adamant it's a sensor, tell them you'll be back when they swapped it out and confirmed it was only a sensor, otherwise you'll assume it'll need a rebuild engine.

BTW, if it does need a replacement engine, 2k-2.5k fix is optimistic unless you're good at rebuilding rotaries. IIRC a reman engine alone from Mazda is something like 3.5k, a reputable rebuilder who'll warranty the engine is likely to charge even more.

RX8s aren't good flips IMHO because there's a fairly limited market for them and a lot of people are scared of the magic doritos. Plus, there are a lot of borderline ones out there that depress the prices for the 04s and 05s.

Just chiming in, since compression tests have been mentioned a few times, but nobody has appears to have said this: Rotaries have their own special compression tester. You have three different rotor sides, and thus, three different chambers passing over a given spark plug hole, so a normal compression tester will tend to tell you your best compression of the three, possibly leaving you blind to failing seals. A rotary compression tester will record each side separately, and give you three numbers.

That's why you'd bring it to Mazda, unless you want to own a specialized tool.

Hot starts have been a issue since the first injected rotary back 1983. Hard starting when cold is a sign of low compression.

In reply to Chas_H:

Could you point me at a source for that info? I've only had a few RX7s but IME when the compression gets low you first notice it on hot starts. By the time it has cold start problems it really wants a rebuild.

I'm the source. I had brand new injected cars in my shop in 1983 that wouldn't hot start.

So what you're saying is that this was a fuel injected problem you experienced in 1983.

I was just curious because everything I've experienced myself with RX7s and RX8s, plus every buyers guide I've ever read categorically states that in contrast to a boinger engine (which is harder to start warm when it's got low compression because it doesn't get the additional help from the thicker oil), a rotary tends to be harder to start when it's hot because the way the rotors and housings expand effectively leads to less compression on a hot start.

In reply to BoxheadTim:

Nope.

Please don't paraphrase my post then expect me to agree to it.

If you have so much experience why do you need the opinion of others? New rotary powered cars generally have excellent compression, yet will have this issue of difficult or no hot start.

The traditional way of knowing an engine was weak, since the 1970s, was that they got difficult to start when hot.

The EFI had its own issues, there was a bug in the software that made flooding easy. This is unrelated. I surely hope that Mazda didn't carry that bug over from L-Jetronic over to EEC-IV.

Compression test from Mazda will tell all. Get it started and have them let you drive it to a dealer for a compression test. If it has good compression then one of the other failure points will cure it on the cheap.

Like everyone has said it has multiple issues that can crop up. If it has flooded and not been properly cleaned out then it can have a problem starting. The starter itself on the early cars is weak and should usually be replaced by the later starter. The coils frequently cause issues if they are old. The plugs could also cause issues.

I was going to ask why no one had mentioned the flooding.

These cars HATE being started and moved a short distance. i.e. on a used dealer lot being shuffled around. There was a TSB at some point telling the dealer to always let the car get to full temp. I think it fouled the plugs if you did not let it get to full temp.

Mad_Ratel wrote: I was going to ask why no one had mentioned the flooding. These cars HATE being started and moved a short distance. i.e. on a used dealer lot being shuffled around. There was a TSB at some point telling the dealer to always let the car get to full temp. I think it fouled the plugs if you did not let it get to full temp.

Oh yeah good call on the plugs getting fouled by getting shuffled in a parking lot. Didn't even think of that! Yup its going to need plugs.

It's not so much fouled plugs as it is compression loss from fuel washing the oil from the internal surfaces. No oil = no compression. Flooding is a positive feedback loop.

Interestingly, modern low-tension ring piston engines can do it too. Nothing more fun than going out to your (timing chain OHC) engine and the starter spins it like it has no spark plugs in it.

I've been looking heavily at RX8s recently too, as they may be a fun fit for my needs. Reading this thread with interest. I contacted a few Mazda service departments, and they all said the same thing. Flooding...you MUST run them to warm once you fire them up. Starting them cold and then shutting it off right away is murder on them, for many reasons. Keep oil in them. They burn oil by design. People coming from piston engine cars don't pay attention to this and have a habit of starving them for oil.

One thing I do like is that Mazda extended the warranty on the engine internals to 8 years or 100k miles from original in service date. That helps a lot. You can pick up a 2009-2011 with low miles for under $12-14k.

clutchsmoke wrote:

Mad_Ratel wrote: I was going to ask why no one had mentioned the flooding. These cars HATE being started and moved a short distance. i.e. on a used dealer lot being shuffled around. There was a TSB at some point telling the dealer to always let the car get to full temp. I think it fouled the plugs if you did not let it get to full temp.

Oh yeah good call on the plugs getting fouled by getting shuffled in a parking lot. Didn't even think of that! Yup its going to need plugs.

Pretty sure you have to do more than just clean up the plugs. IIRC they had to clean out the throttle body or MAF or both when my wife flooded my car moving it from outside the garage to inside in 30 degree weather without warming it.