Drive-Maniac

Hello guys,
I recently bought an RX-8 el cheapo. The car starts, but smokes really bad like a 2 stroke engine and has no power. I drained the oil and it is flooded with gasoline. Plugged an OBD reader and the CEL is "Random misfire".
Since the car starts, I was thinking is this a bad engine? Looks like it has a compression of some sort.
I read a lot in the forums here about these cars that failed coils are a common problem.
Do you think this can be the issue?

Any opinion is appreciated!

Thanks

Johny5

It could very well be the coils and plugs, but a conpression test will be the only way to tell. I could be wrong i am not an expert on these engines yet.

Loki

iTrader: (1)

Bad engine wouldn't have gas in the oil, it doesn't fail that way. Definitelt check/replace the coils and spark plugs. In fact pull the spark plugs, you'll see right away what's burning and what isn't.

You could try rotating the leading coils to the trailing positions, the leading do most of the work, so if one or both have failed, but the trailing are still healthy, you should see an improvement if you swap them around. That's not a permanent solution though, just a cheap way to confirm diagnosis.

CelestialGryphon

iTrader: (1)

In the end, if your coils are going out you should probably get around to replacing the ENTIRE ignition system at the same time. Plugs, Coils, Wires. The most "cost effective" way is with the BHR kit which comes with a lifetime warranty and MSD wires and can be ordered with plugs as well. (Notice I said IF. Diagnose first, replace parts if needed.) It could be something as simple as ***** plugs, and the coils could be fine. However... if you've got no clue if the coils have ever been replaced... I'd replace the coils regardless.

lOOkatme

could be a couple of things.




bad coolant seal if your coolant level is going down. run some kseal through the coolant and it might fix itself.


it could be bad ignition coils causing the misfires, hence the extra fuel you see.




also might want to run some water through the engine if its carboned up.

Drive-Maniac

Well, update on the case, today I diagnosed the coils. 2 coils are bad, the trailing ones. Removed the plugs, there is no carbon on them, very wet and clean. I filled with fresh oil and will try to get 2 coils from the junkyard just to test it. I don't want to spend money on new ones if the engine is not good. Odo says 190k km., I guess it is probably on the edge.
My plan was to do a 4g63 swap on this car. But if the engine is still good, I will keep it as is.

THANK YOU so much for your help! We'll see how it goes...

CelestialGryphon

iTrader: (1)

If you can get a compression test, a rotary specific compression test, do so. That'll give you an idea of your engine's healthy. If it passes the test, or at least is in good enough shape (low 8's) you might as well go for new coils and plugs and wires.

Drive-Maniac

Bad news Found some coils and changed the damaged ones. Did a simple compression test and my rear rotor has no compression at all. Front one has around 5, which is still low.
I guess I gotta open it up to see what is going on in there.

NotAPreppie

If you've never rebuilt a rotary, think twice about doing this yourself.

Drive-Maniac

Thanks, I have no experience with rotary.
Actually I am still considering swap, if this engine is damaged badly.
Does a NO compression mean apex seals for sure?

Johny5

Sorry to hear that its an expensive and very labor intensive job. Take your time and ask plenty of questions along the way. Make sure you keep every nut, bolt and screw organized and labeled in bags. Take alot of pictures along the way for refernce incase you forget how to put back together. Not everyone will support you but those of us who do will give you any help we can along the way.

lOOkatme

do a water treatment to see if its just carboned up engine. run 32oz of water through it through the service ports on the LIM and see if the compression comes back. also run some 2 cycle oil with the fuel (1oz per 1 gal).


does the car have cold start issues?

Johny5

From what i have been reading on these engines it can be alot of things that contribute to low or no conpression.
1.Could be carbon buildup in the grooves of the rotor not allowing the apex seals to do there job.
2. If the motor was overheated it could be warped rotor housongs.
3.the springs themselves that push the seal against the housong could be weak.
4.could just be worn out and the apex and side seals are just to worn.

I have no conpression in the 04 i picked up and have been hesitant to tear it apart right away been doing some troubleshooting here and there just to see if i can get her to even fire up but have had no luck at all. The guy i bought it from overheated it. He took it to mazda they said needs a motor then he sold it to me. He didnt even ask qhy it overheated so even when i do get her rebuilt and running i have to find that problem quick. Gonna put a new coolant system in while i am at it just so i know i narrow the problem down

lOOkatme

What would cause it to overheat? thermostat, water pump is bad? etc, etc.

Johny5

Yeah basically the most common cause of overheating that i have read in the forums is the magical cracked overflow bottle that went unoticed. The more sever problems which i havent read or really noticed anyone talking about are the water seals inside the motor.

Loki

iTrader: (1)

I didn't think a car with no compression in one rotor and low in the other could start. What did you test it with?
Did you measure through the leading or trailing plug hole and did you leave whichever one you were not measuring through plugged?

Drive-Maniac

Well, as I mentioned in the first post, the cars starts, but runs like a 2 stroke engine, smokes a lot, sound like a tractor, very rough and has no power. After I bought it, I found that 2 coils are bad, the trailing ones. I borrowed 2 coils from a junkyard just for testing. I decided to measure the compression with a regular gauge, just to see what is going on. Then I found out that rear rotor has no compression at all. Seriously, the needle on the gauge does not even move. I measured only leading ports. Forgot to mention that plugs don't have carbon on them, but they may have been changed, who knows.
I just hope that stators and rotors are usable, so I can rebuild it. Otherwise I will start thinking about a swap. I really like this car and want to bring it back on the road
Thanks everyone for your help!

Loki

iTrader: (1)

That's what I find weird. It should be able to start at all on one nearly dead rotor. So just want to make sure the test was performed correctly. Nothing personal, but we get all kinds through here. You did keep the trailing spark plugs in while performing the test, right?

lOOkatme

run kseal through the coolant. it might be a small coolant leak. this will show as loss of compression. it will also make the spark plugs wet having the car run like crap and be harder to start. the kseal, magical stuff, will go through and block up the leak. supposed to be a permenant fix and worked on my coolant leak I had.

Drive-Maniac

I know it is weird. Even the trailing coils are bad, rear rotor is dead, that means the car starts just on the front leading rotor working 😃
Could it be any of the seals inside, I noticed oil all around the oilpan. I guess I will try the water test first.

Johny5

You need to get a proper compression test done. At this point it is alot of guessing and alot of money fixing things that may not be a problem. Even with the regular conoression tester you said no compression at all in the rear rotor and low conpression in the front. There is absolutely no way the car would even start. Thats like starting a v6 on three very weak cylinders and the other three are toast its just not going to happen.

Drive-Maniac

What is the point to get a proper compression test when the basic fails? It is gonna show me zeros all across for sure. Actually in my area there is not such a place where I can do it.
Guys, I know stuff about cars, I have built couple of DSM's and own a 10sec one.
I can rebuild this engine for sure, just I wouldn't like to spend 1.5K on parts. My first plan was to make a swap. And in the process I was thinking that this engine may not be dead, just because it starts.
Again, I have never seen a rotary engine and never knew how it works. I guess I will learn now
Can someone tell me how exactly is this water treatment done?

Thank you in advance!

CelestialGryphon

iTrader: (1)

A basic compression test isn't the same as a proper compression test, which is going to check the 3 facings on the rotors. You can get imaginary zeros across the board by doing it incorrectly, or you can get accurate numbers by doing it correctly. That decision is entirely yours. A DSM is not a rotary. It may NOT be dead. It might have usable but low compression, which means it's possible to salvage it for a little while as a usable engine. As far as "the water treatment" Just look up Rotary Decarbonization Process. The theory is the same, the chemicals different. It's all a more or less thing. Look at it this way - Liken the RX8, and the Renesis to a long distance shooting rifle. When all it's parts are in symphony, you'll get the most accurate results when everything is honed at it's best, all parts adjusted correctly and maintained and procedures followed.

Loki

iTrader: (1)

If you don't plan to spend $1500 on parts, rebuilding may not be the direction you want to go. Often, people who open these engines find they need more than just a set of seals and gaskets. Say you need a new housing or two, you've just busted the $1500 budget. That's why around here we usually recommend buying a good engine from a professional rebuilder like Pineapple, Pettit, etc. It's more expensive, but saves so many headaches.

But at that point... there is no good direction to go, since swaps are even more expensive to make work, thousands and thousands of dollars in electronics and custom work.

Drive-Maniac

With a budget of $2000 I will make a good reliable 300hp swap. I will open up a thread as soon as I start it, probably after the holidays.
I will need your help to get all electronics to work, that is for sure.

Thanks guys,