crunchywaffle

As my title says my rx8 has started to become a beast to start, especially since it’s gotten cold here in snow land. I’m familiar with rotary engines as I own an Fc and fb but since my rx8 is my daily I’m hesitant to rebuild it. I just wanted to know if it’s worth looking into my starter and ignition system before ripping the car apart, I’ve read those are common problems on our cars. My rx8 is a 2004 manual base. The rx8 is a bit more intimidating then my rx7s so any advice is appreciated. Thanks!!

a little more description on my cranking issue- when the car is cold it takes a good bit to start but will often start faster then when it’s hot. Starting the car it will start trying to fire but only after holding the key for much longer will the rpms actually raise to running condition.

- I should also mention the car will smoke occasionally and this is absolute beyond me.. I would think oil rings but it’s such a rare occurrence I’m not sure at all haha

CaymanRotary

Best to diagnose the engine rather than just rip it apart. You'll first want to do a compression test on the engine to ensure its still healthy. If it passes, then go ahead and change out ignition parts. Upgraded 2Kw starter, plugs, coils and wires, but always best to have those parts tested before replacement. Any engine codes? If its smoking it could just be running rich.

crunchywaffle

It does have a few engine codes it’s had since I bought it. The one is a secondary air injection code that I’ve tried to fix by replacing the solenoids on the back of the manifold. And the second code is a cat efficiency code because tossed that junk in the trash. It also has a “cylinder” 2 miss fire in the high rpms in second gear. I tried to fix this by replacing the plugs but it came back a few days later. I’ll for sure do a compression test, I just wondered if it was worth doing the ignition and starter before I rip the wheel off and throw a compression tester on it. I work at a shop but because of how busy it is I would have to wait to use a hoist, so things I could do in the engine bay would be nice haha

MincVinyl

So lets start with the smoke issue. Because this may lead to part of the cause of the starting issue.

If it is white smoke it could be normal cold weather condensation or it could be blown coolant seals which typically shows as plumes of thick white smoke, smells sweet, burns the eyes/throat, low coolant.....this can/will increase in severity as the coolant seal continues to break down allowing more coolant into the combustion chamber. Burning coolant leads to fouled spark plugs and long hard cold starts. The coolant seals will reseal once the car gets higher in temperature and expansion occurs, thus the smoking may stop by itself.>>rebuild incoming

Dark blue smoke is an indication of oil burning, this should be less common in Rx8s due to an additional oil seal on the rotor. If it is bad enough I suppose too much oil buildup in the chambers can coat the plugs causing fouling. >>rebuild incoming

Edit: I took too long to post, Since you messed around with the cat, you could be having issues with the O2 sensor causing the car to run rich for some reason.

Regardless checking the smoke and how the leading plugs look may help give an indication. Plenty of fouled plug examples to compare different issues.
--------------
Other options

• Getting a new set of plugs if you haven't already wouldn't hurt, but again check them first. Plugs will be my best bet for helping to have easier starts, but they mean you have another problem happening. ~80$ new
• Many upgrade to the higher powered starter, can report what rpm your start is spinning when this issue occurs. (think I have 3 of them now if you live near southern new hampshire) ~$80-100 new
• High CCA battery, pretty sure the Optima red tops are still the highest CCA you can get. They can tend to die within a year or two though. If I remember back to my autozone days they had changed their production to somewhere in south america and are made much lower quality than what they used to be. I went through 3 of them at autozone's expense within a 2 year period.
• Always the chance you might have dying coils, plenty of threads on the issues with old coils. Your choice to get stock coils again or go to an LS kit.

crunchywaffle

I’m familiar with failed coolant seals (that’s why I’ve rebuild my fc lol) but I’m lead to believe it isn’t that as the smoke only comes at random while running at high revs and the car starts on both rotors. I also have already thrown a set of plugs in and the only fouling on the plugs I found was from the two stroke oil I’ve been running in the fuel. I’ll check the plugs again to see if they have been fouled already as I installed them probably 4 months ago. The car also has 170k kms on what I can only imagine are oem stock coils and starter

crunchywaffle

I’m really trying to avoid a rebuild at all cost, I’m already neck deep with my rx7 so if I can squeeze 6 more months out of this engine I’d be fine with that. I actually already have another 13b waiting to be rebuilt to throw in the rx8. I can only put the funds in one direction atm

MincVinyl

Well at least it is sounding more like an ignition problem then. If the stock cat was bad one of the usual suspects is bad coils.

It can be fairly quickly that the plugs get fouled, when I had blown coolant seals to get through college my plugs lasted about 2-3 months.

I found premixing with ignition problems accelerated my plugs being fouled. Went back to just the omp with the sohn 2stroke oil adapter.

Loki

iTrader: (1)

If you don't do the ignition, replace the engine, and continue running a poor ignition, you'll be back here in 5000 miles. Better to properly find the problem while the engine is still in the car.

Also don't rebuild your engine. Get a rebuilt one, you will save money, headaches and it will run longer.

Premix doesn't foul plugs unless you're running silly amounts of premix. It's specifically made to not do that. If a plug is fouling, it's probably not firing.

You said you have smoke at high rpms? Is there oil in your intake? That's not uncommon for an engine that's on it's way out. You can install a catch can to at least prevent that from happening.

What rpm is your starter turning at? If it's down around 200, a new starter will help you start easier.

MincVinyl

Can agree with loki, learning to rebuild a renesis is a pain.

CaymanRotary

The only real way to confirm if the engine is bad is to compression test it. Get some results and post them here.

crunchywaffle

Alright I’ll make sure I compression test it before I dig any deeper. The car fired up great this morning, all these little issue that come and go drive me crazy lol. Also I didn’t know the rx8 was much different to rebuild then a regular 13bt, what makes them different and is a fresh engine something I can get from Mazda?

also I’d just like to say thanks to everyone who’s helped out!! You guys are awesome.

CaymanRotary

You can get remanufactured engines from Mazda or from a rebuilder like Rotary Resurrection for example. It is very similar to rebuilding any other rotary engine so if you have experience with it, go for it.

crunchywaffle

That’s what I thought haha, I was going to do a half bridge while I was in there so I’d prefer to rebuild it myself anyway. I’ve rebuilt a couple of these so I’m familiar with them. Also if anyone could point me in the right direction towards rebuild kits I’d appreciate that. If Mazda sells I kit I’d appreciate a part number as I can usually get parts at cost from Mazda.

CaymanRotary

Bridge or street ports are not needed on this engine. Port polishing is all that is required. All it will do is mess with your idle if leaving car mostly stock. You will also need to order your rebuild kit AFTER you tear the engine down. It depends what is needed. May also need to replace rotors / housings. If the engine requires too much, it would be better to just order a new engine.

dannobre

iTrader: (3)

If its hard to start cold and starts OK warm you could have a coil or ignition problem... or an injector that isn't spraying very well also. Get the compression check... and look at the plugs. Cause if the fuel isn't atomizing properly and you have poor spark it won't start very well.... especially when it's cold

crunchywaffle

the car actually starts better when it’s ice cold. I just came back from the grocery store and flooded it try to start it to come home. Had the old lady sweating in the passenger seat.

dannobre

iTrader: (3)

Then the compression test is what you need.

With 3 rotaries might be worth buying a tester 😄

crunchywaffle

you're probably right, might be a worth while investment lol like I said I’ll make sure to just throw a normal compression tester on it Monday so I’ve got an idea. I did notice however, by cranking speed did seem extremely slow compared to videos I’ve seen. It’s got a brand new Napa gold battery (700 CCa I think) so I’m pretty positive that isn’t it. If the numbers come back as low compression I’ll just overhaul everything. New starter, Ls ignition, and a rebuild.

UnknownJinX

The early manual starters are underpowered, but if the compression is low, that's just a band-aid fix.

crunchywaffle

to be totally honest all I’m looking for at this point is a band-aid fix. All my money is tied into my rx7 so if I were to take on another project I’d likely not be able to finish either. As long as my rx8 gets me to and from work for a few more months, that’s all I need. If the compression test comes back with crazy low numbers I might just have to park it for awhile or trade it. That’s why I’m really just trying to buy time haha

-on a normal compression tester what kind of numbers should I be seeing?? What’s good compression and what’s acceptable compression??

CaymanRotary

Unfortunately, it's not as simple as just hooking the tester in and looking at the number. This is the best video I've seen on how to test using a regular tester. He says it's easy but it's really not lol. On top of that, it won't be completely accurate but will be close.

Loki

iTrader: (1)

Depends on RPM. Rotary compression changes quite a bit between 200rpm and 300rpm, so testing with a regular tester is eh, a good way to find out if you have catastrophic damage, or a very healthy engine, but its not precise enough to distinguish which side of borderline youre on.

At 250 rpm, you;re going for 6.9kg/cm2 or better, so about 98psi+. Here is how that changes with rpm.
BUT! If youre not correctly accounting for dead volume in the meter itself it could read low. And you have to remove the shrader valve so you see each faces spike, not just the total. Having 3 RXs, I imagine that part is familiar.



There are youtubers who do DIY videos of testing with a regular tester and the mistakes have been pointed out to them. Its *fine* but when youre trying to decide whether or not to spend $5k, maybe some better equipment is in order.

crunchywaffle

Alright I’ll watch that video and report back when I’ve got some numbers. Nothing can get done this weekend regardless so for now I’ll just pray I don’t stall in traffic 🤣

thanks a bunch everyone!!

CaymanRotary

Loki is right though. It's much better to source a rotary tester when making a determination of whether to rebuild or not. This way with a normal tester is simply to give a rough idea of how healthy the engine is.

crunchywaffle

I’ll be sure to put an order in for a proper compression tester. As soon as I’ve got another set of wheels to drive me around the rx8 is getting a fresh built anyway, but for now I just need an idea of how much longer I’ve got before I go out for work and end up walking. I’m familiar with using a standard tester on older rotaries but it’s good to see a video just so I can be sure. While the car is up in the air I’ll check for spark intensity as well just so I can double check everything.