agbankert@me.com

Can anyone please help me? I miss driving her so much. Lol. I'm a avid and pretty skilled mechanic. I love rotories but this has been a pain. I rebuilt it with all new/barely used parts. All clearances and everything was done to the book. To the letter. And now it just cranks all day but no start. Figuring it was a grounding or injector connection problem I went through it again and everything seems perfect. It's getting air, fuel (sometimes too much LoL), compression, and spark but yet no start. So I tow started it and it sat there and idled perfectly. I could get out and let it idle on its own. So now I'm thinking it's not spinning fast enough to start, not enough current, but the battery is charged and passes the load test. Grounds seem to be solid. I'm dumbfounded. I did everything. Deflooding over and over, brake stomp, I know for a fact that the injector and spark plug wires are correct, etc. It can't be stuck in limp mode because the engine started before the rebuild (off of one rotor though &#128521. This is not my first engine rebuild but it is my first rotary rebuild is there any simple mistakes first time rotary rebuilders make? I have done research online, in person, and over the phone, and I'm lost. I'm at a dead end. I don't want to sell it as it was once an amazing peice of driving machine. Thank you ahead of time!

Loki

iTrader: (1)

Hmmmm. I would try to get some sensor data while it's running (if you can pullstart it again). Not sure if it's had time to learn any fuel trims, but check them anyway. Check also airflow g/sec at idle. At this point we're looking for things that could have gone wrong during the install.

It's normal for the engine to be down on compression just after a rebuild, but it will come up as everything settles in. Suggest taking it for a drive at varying rpm's (but don't beat on it).

dannobre

iTrader: (3)

When you pull started it did it run normally? IE did the throttle work and did it rev up?

I would pull start it and let it idle...and drive it carefully for a while as well.....

agbankert@me.com

Sorry about the late response! I have put the rx8 aside for now while life settles down. But i pulled started it and it idled beautifully!! Then it dies after a while. So I determined it was just running off of the flooded fuel inside the engine trying to start it. So it must be fuel side of the engine. So I took it for a test drive around the neighborhood and I pushed it a little bit. And it would choke out after about 6 Rpms. I checked all the injectors and they are perfect. And now it started making a loud noice that sounds like something is bouncing around somewhere. I thought it was coming from the engine. But my buddy swears it's the transmission. I'm about to the point where I'm going to take it to a rotary shop. But before I do, have any advice?

9krpmrx8

iTrader: (46)

Rebuild for your rebuild time.

Loki

iTrader: (1)

Chocking at high rpm and bouncing noise could easily be your catalytic converter being clogged from failed coils. And that could be what killed the first engine. Bring it to a rotary shop for a second opinion.

agbankert@me.com

The cat is hollowed. Bought it that way.

Reoze

Have you actually verified that was done correctly? People can say anything.

agbankert@me.com

yes I did it myself along with a master mechanic of 40+ years. The engine is perfect. Has compression, fuel (and lots of it) air and spark. No way it shouldn't run beautifully. Could it be an ecu?

im fine with rebuilding it one more time I just don't see it being necessary to do so. I've already ripped this motor out three times to make sure it was done right. It is. I'm 99% certain it's a good engine. It's gotta be something out side of the engine.

9krpmrx8

iTrader: (46)

Everyone who rebuilds an engine and then ends up having to pull it and rebuild it again was previously 99% certain it was a good engine.

Have you and your "master mechanic" even done a compression test the right way using a rotary engine compression tester?

agbankert@me.com

We've checked and double checked and triple checked to make sure everything was to the book what Mazda tells their rotary technicians what to do. And no. It's got plenty of compression more than it did before. Granted I only used my fingers in the spark plugs but I did that to the old engine which had poor compression which led to its failure. I changed the spark plugs in the old engine and did the same test. It has plenty of compression to be able to run. But what I could do is use a piston compression tester and take out the schrader valve and record with my slo mo on my phone which I planned on doing soon anyway.

9krpmrx8

iTrader: (46)

Good luck buddy.

Reoze

You listed off just about everything that could potentially be an issue and said they're all good. It's one of those things you listed. You need to figure out which one. Saying they're all fine is going to get you nowhere.

Testing compression with your finger is a lot like testing an electrical outlet with your tongue. There's some sort of compression, that's all you can tell with a finger. If you had compression on one face of the rotor but not the other two, you'd never know.

What are you using to test the spark? Are the coils wired in the correct order? Have you tried swapping them with known good coils?

How are you determining that the airflow is "good"? Do you have a reading off the MAF?

agbankert@me.com

I'm thinking it's fuel if I'm honestly. It floods too quickly and yes I know these engines do but I know how long it takes to flood and it's just too quick to flood than normal. And then it will run perfectly until it burns off the flooded fuel. So I'm guessing it's fuel. But I have pressure not sure how much though. But you say it's like using your tongue on an outlet but you can tell the difference between a 9v battery and a 12v battery on your tongue. Just like I could tell the difference if the rotor is pulling my finger more on each face. There's the pulls one for each face and I can tell if one face is weaker. But you're right it doesn't hold up to actually having a test done so I'll be sure to do that soon.

But I'm testing the spark by grounding out the plug and turning the motor over and watching the spark. It throws a bright blue spark. They are new spark plugs wires and coils. Cause I thought that was the problem with old engine. And I know the air is good because I pushed air through the accordion with a huge compressor. And I sprayed starter fluid with it and it tried to start with the starter fluid which also leads me to believe that it's fuel side.

agbankert@me.com

I don't have any computer testing equipment to test the car's system. So i don't know numbers which could also be a huge problem on why I don't know what's wrong with it. But by redneck testing I can pretty much say it has everything it needs to run. But there's something I did wrong and I'm just trying to figure it out. I fully rebuilt a 5.7 hemi and it runs beautifully still to this day. Nothing wrong with it. Just to justify that yes I'm no where near the best mechanic but I should be able to figure out what's wrong with it.

Loki

iTrader: (1)

Running off flooded fuel is not a thing. This isn't a carburetor.
It clearly doesn't have everything it needs to run, so let's look at the facts and start again.

If it's flooding, clearly you're getting fuel, so clearly, this isn't a fuel problem.

Like it or not, this car is run by a computer. It can be your friend, or you can try to fight it. Get an OBD reader for $15, get a compression tester and get some numbers. Get an induction timing light.

Compressor in the accordion tube? You realize that you're just blowing it against the throttle plate, which gets you absolutely nowhere. And you've probably disconnected the MAF to do this, so it definitely won't run like that.

agbankert@me.com

Hey everyone. I just wanted to inform you all that I was desperate and wanted answers. I did my best but rotaries are way different than pistons. I’ve learned that. Lol. At the time I posted I had a kid with my now wife and needed a ride to go to the store and work. I hope that clearifies my responses. Lol. However, 2 years later after my first motor blew I’m at the same point I was. I never clearified my problem with that engine however I dubbed it as a compression issue because of the housing. I eventually did do a compression test and the front rotor was perfect and the rear rotor almost had none. I replaced that motor with a reman I bought and it too had starting problems. I pull started that one and same thing, it idled perfectly. Rev’d up fine. But as soon I got it warmed up and I revd it put it chocked at 6-7k. Then I found out that I worn through a rotor main bearing which was most likely due to not having any accurate gauges telling me my oil pressure. I rebuilt that engine and this is where I’m at now. Compression is low but so is rpm. With calulations I got an rpm of 195 (even with a new starter) at 33: 35: 45 PSI. Specifically what do you guys think it is? Please don’t give me any flank. I’m trying to learn these engines because I think that they are well worth it when you’re going through a turn at 7-8k screaming on by like it’s nothing. I have full faith in the design but if I can’t get help I’m going to lose faith in these motors. I’d rather learn about them rather than having someone say “have someone who knows what they are doing do it because you’re not smart enough” you know? I’m smart enough I just don’t have the knowledge quite yet to figure out every single problem with these engines. But I want to!! At the time of posting this update I have three kids now and I don’t want my wife’s Cadillac to be the best vehicle on our garage. I just want to know exactly what could be the cause of this? Seals are good I bought them off from Atkins.

Loki

iTrader: (1)

When you rebuilt it, did you reuse the housings? Seals are part of the equation, the other parts are the housing and the irons. If they are scored, worn or flaking, or otherwise out of spec, you're not going to build compression.

Did you cut the seals to the correct clearance when you did the rebuild?

It's fairly normal for the compression to be low on a fresh rebuild, it will wear in once it is running. If your starting rpm is low, you need a new starter. This is pretty common with older RX8s.

Shaozhou Zhang

First of all 195rpm does not seem to be high. Normalizing your compression here or type in "rotary engine compression normalizing".

After normalizing to 250rpm (I do not know the altitude in your place so I put 0 in altitude).
The results are 38.92, 41.28, 40.10. Unit: PSI RPM:250
These are pretty low numbers, even lower than the minimum numbers on the graph I've seen
How is your engine even running?
Try to put some oil via the spark plug hole, this should help with your compression.
Have you been doing premix and is your OMP system working?
You need at least either of this, idealy both, if not, there will be no oil in the chamber that helps with sealing, and there will be excessive wear on the seals.

Fijibluefg2

First off, congrats on your dedication to this poor RX-8. I lost count but seems you’ve pulled the engine(s) out of the car like 10 times by now. That has got to be some kind of record.

Second, although I fully understand your desire to learn the inner workings of these engines yourself, some things are better left to a professional.

Think about it, you could have throw in a properly rebuilt engine THE FIRST TIME and could have been driving the car ALL THESE YEARS instead of it being on jack stands and you wasting year after year wrenching on it over and over in your spare time (instead of being with the wife and kids). I’m sorry but it seems like wasted LIFE to me bro.

Fawk even trying to learn the Rotary. Wankel himself couldn’t do it. Mazda has been trying for what, over 30 years now and still can’t make a reliable, fuel efficient and smog compliant engine, so what makes you think your backyard mechanic skills can do better? Lol.

These engines are literally designed to be enjoyed for xx,xxx amount of miles and then TRASHED, Throw away and replaced with a healthy engine during your lunch break and be back on the road enjoying the car by 5pm.

You’ve killed so much time and money by this point that I’m literally depressed just reading your story. I wanna shake your hand in awe and give you my keys for a joyride.

Goodness gracious.