Okay, new thread since my old one is not relevant anymore. Bought a non-running car and rebuilt the engine, now I'm trying to start it but it won't catch.


Spark:
I suspected the coils were bad and replaced them with LS2 coils, and verified they are sparking. Also did the 20 brake tap reset and verified the position plate is on correctly.

Fuel:
The car sat for a bit, so I drained the tank of fuel, but I recognize that since it's not a return flow system, is it possible there's just a bunch of bad gas in the line? I can smell fuel when I try to start it, and I pulled off the fuel line connection (which I double checked the colors were correct) and some fuel came out. I can also hear the pump prime so I assume I have fuel pressure.

Compression:
Well, new engine. It made a good pop when I kicked it over by hand before putting it in.

As for the installation, I primed the oil system and filled the coolant, was there anything special that should have been done for the fuel system other than turning the key a few times to prime the pump?

Any help appreciated!

 

Did you actually check fuel pressure? The RX-8 fuel system runs at 60psi, so if you took the hose off while it was running, it should be way more than "some fuel".

And does the car crank?

 

Sorry, should have said I pulled the hose off after I had been trying to start it but with the key off. I don't have a fuel pressure gauge though, and didn't see it on the list of values on my OBDII scanner. In an attempt to drain any potential bad gas from the fuel lines, I connected some tubing and turned the key on and off and it put a lot of fuel into the jug.

Yeah the car cranks, but it doesn't even sound like it 'wants' to start. Cranking speed is 200-something RPM but it never creeps up like it's beginning to fire.

 

Is it possible to flood an engine just from cranking it when it won't start for other reasons? Just wondering if I should try a flood clear procedure.

been reading and found some similar threads where people suggest some oil in the spark plug hole on a new engine to help bring compression up. Will try tonight.

 

Yes it is possible to flood it. You need to properly troubleshoot the issue, if you don't you will get no where.

http://foxed.ca/rx7manual/2003mazdar..._S01_0016.html

 

Thanks. Had a read through that and I'm starting to think it's low compression. Been reading around elsewhere on here about people having trouble starting fresh rebuilds because they aren't making enough compression.

I followed the de-flood procedure (and got a cloud of vapor when the plugs were out), added some oil, tried again but still nothing. Taped the button down on my compression tester and got 60 psi on all faces on the front rotor, but the back one gave 60 on one side and 30 or so on the other two. Cranking at 230-250 rpm according to the obd2 reader. That would mean stuck apex or corner seal, right? Would that be enough for it not to start? Everything was moving freely when I assembled, but I have also read of hylomar squeezing into the chambers and making seals sticky until it burns off. I didn't go nuts with the stuff or anything, but I do wonder if it's a possibility, so I thought I should mention that I even used it.

 

That is pretty low. You could try push starting it. I have seen some home built rebuilds need some run time before they will idle on their own.

 

Yeah, and it being an 05 with (I think) the original starter doesn't help. I also read something about heating the plugs, might try that tomorrow. Its been in the low 40s Fahrenheit so I guess that might not be doing me any favors either...

 

Heat has nothing to do with it. It is either a botched rebuild (most likely) or some slightly stuck seals that should free up when the assembly gunk gets burnt out. The 09+ starter would definitely help but a push start accomplishes the same thing. If you get it started, go drive it for a good bit.

My buddy rebuilt his engine and it took a few days of driving before it would idle without stalling. Then he drove it from Texas to PA and it runs just fine. It's tricky, and rebuilding a rotary is not as simple as most think.

 

Well, I was very careful with all my seal fitting, so I really hope it's not botched but certainly can't rule it out. Going to check the strength of the spark from my coils, give the apex seals a tap through the spark plug holes, try a bit of atf and then tow start. Thanks for all the advice by the way, much appreciated!

 

Two threads on the same subject? Good job.

 

Negative. As stated in the first paragraph of the original post, they are different issues. Spark issue has been solved and then I created this thread after. I push started it as you suggested and it fired right up. Haven't had too too much time to run it yet but that's my plan for the long weekend. Thanks again, and good call about it needing run time. First rebuild and simultaneously first rotary, I knew it'd be a challenge!