Edit:

Got it running. 2 coils are out. Just switched the 2 working coils for the trailing side and car starts and runs now.


Some times it still wants wants not to run properly and wants to just shutdown.

I got it idling at 800rpm? Sounds about right. But after turning it off and going to turn it back on after 10 minutes, it would not stay on without foot on gas.


After having it on for like 5 minutes it started to stay on by itself.

Any ideas?

Ordering 2 or more coils for the leading side now

Hey. Just rebuilt my engine. All seals etc. Now the issue is idle and getting it started.

Starting the engine is a mystery. Sometimes I can get it running quite fast but if I let the car turn off and I try to crank it again it wont start..

Car wont stay on if I let my foot off the gas pedal. It literally turns off instantly if I lift my foot.

First time starting I got 2nd rotor missfire code.

Swapped 1 and 2 rotor coils and now there is no CEL for that or flashing but the car still wont stay on and is hard to start.

Car is also pushing alot of unburned fuel out If I am correct 🤔

car also runs and sounds like a 90's lawn mower? 🤣

Tips what to check next / do next / etc

 

Go over your injector and coil/spark plug wiring. It's extremely easy to mix up injectors.

Are seals the only thing you changed?

 

I bought the car knowing "it had bad compression, it has been sitting for 3 years".

I rebuilt it inspected all the components while rebuilding with new set of rotor seals, all gaskets, o rings etc.

Did not touch sensors, coils, or their wires yet.

Got new ngk plugs tho.

 

Coils wires and cats would be obvious things to check/replace since they're probably what killed the first engine.

 

Got it running. 2 coils are out. Just switched the 2 working coils for the trailing side and car starts and runs now.


Some times it still wants wants not to run properly and wants to just shutdown.

I got it idling at 800rpm? Sounds about right. But after turning it off and going to turn it back on after 10 minutes, it would not stay on without foot on gas.


After having it on for like 5 minutes like that it started to stay on by itself.

Any ideas?

 

The car needs to learn to idle after having the battery disconnected. If it had 2 bad coils, a new engine and throttle inputs to deal with, it probably learned badly initially. If it still has difficulty after a couple of drives you can dig deeper.

 

Gotcha.

I started once cold again and idle is getting alot better now.

Only issue is medium amount of smoke coming out of exhaust now.

Someone would call it coolant seal failure but I highly doubt it since they are fresh. I highly doubt they are bad already or installed wrong. Didn't see any of them fall atleast when lowering the housing.

Should I worry and when?

 

Keep an eye on the coolant level. I'd worry if you're losing it, otherwise look for other causes. Is it fuel smoke (meaning super rich mixture) or oil smoke? What are the fuel trims on a warm idle?

 

​​​​​​I let it sit for the night and started it this morning. Everything seems fine, cold start goes up to 2k+ rpm. Slowly coming down to 1k. No smoke anymore. Bit rich on the gasoline smell.

Ill be ordering some coils to make the other plugs do work aswell and new battery.

There is a mysterious rattling noise when quickly stepping on the gas and making the rpm go to 2k.

Very mysterious and cant pinpoint. Sounds a bit as if its one of the valves 🤷‍♂️

We'll see.

 

I'm experiencing a similar issue with my car not being willing to idle after I rebuilt the engine. The car starts and idles easily when cold (it idles at 1200 rpm more on that later), but once the temp reaches about 140, the idle cuts out and the car dies and is difficult to start after. I have a new D585 coil kit from Trex Performance installed, new ESS, new O2 Sensors, new MAF, new stock intake, new fuel pump, and a catless exhaust. I experienced the same issue before installing all these parts and sensors with no change. My LTFT is always 0% and never budges, my STFT is consistently at -25%. The fuel system status is also frequently in a "Closed loop with fault". The car idles around 1200 rpm, but I've smoke-tested for vacuum leaks with no luck. I'm running out of ideas on things to check. I have versa tuner logs with loads of recorded parameters, so if anyone has any ideas I can look at the logs. I ordered a compression tester, but I hope that it isn't a compression issue after a rebuild.

I would've started my own thread but I do not have permission. I figured this was the closest fitting thread to my issue. I have also avoided asking for help from here as long as possible because I wanted to exhaust everything I could think of before taking anyone else's time to solve my issue.

 

You can start your own thread in the new members section. First guess is your injectors are miswired, go over them again. There's a beige wire and a yellow wire, very easy to mix up.

 

You were right. I had swapped my injectors. Switched them and now the car idles great. Thanks for the suggestion!

 

Dammit, I had the same issue that I resolved by installing new Plug wires and spark plugs, couple coils and several EGR valves.
However, I'm still trying to figure out why the engine shuts off after driving it for 60 minutes. I just bought it and have it in storage.
I am just a DIY guy with a little bit of mechanical skills.
Do any of you Houston Rx-8 Forum members know of a good Mazda RX-8 mechanic that yall can recommend?

 

I would start by verifying that the engine compression is good. No sense in throwing money at a tired engine, as you would only be masking an issue, not resolving it. You can buy time on a tired engine with new ignition components, a good battery, and a 2kw starter but it only lasts for so long. This is where I would personally start.

 

This car doesn't have EGR?
Definitely get a compression test but also verify you're not overheating.
It's a good idea to change all 4 coils at the same time, because the remaining ones are a liability. Bad coils kill engines.

Rx8help.com for all your new owner info needs.

 

Runs good but after an hour it shuts off?
what is fuel level when it acts up? Bad fuel pump will get hot with lower fuel levels and kill the car.

Hauling down I-20 to Atlanta car just shut off, pulled to side checked a few things fired right back up.
Hour later same thing, getting low on gas. Filled it up, good for 2 hours until level got down to half and same thing.
Changed fuel pump module and no more issues.

 

around 3/8 - 1/2 tank and the engine quitting could indicate the siphon isn’t pulling fuel from the passenger side over to the driver side where the fuel pump is located. A weak pump can cause this too. So the pump doesn’t overheat, it runs the driver side empty and the engine dies while the fuel gauge is reading the fuel level over on the passenger side.
.