Rock Hopper

Okay guys I've got something driving me nuts.

Some history - 2005 Rx8 manual tranny. Over the last couple years my engine has been cranking slower and taking longer to fire. I have 55k on it and up until a couple days ago I everything was stock (coils, starter, etc). I've had it in to Mazda a couple times and they replaced the leading plugs for recalls I believe but that was all done within the first 16K.

So yesterday I put in a used starter I got from a local wrecking yard just to see if I noticed a difference. Seems like it turns a bit faster and the car fires over quicker but still not stock. I have noticed that my positive terminal on my battery won't get real tight and I can usually get it to move without even loosening it but it's as tight as it'll get. So last night I'm at autozone comparing my starter to a brand new Duralast and I mention my battery post issue. The salesman recommends some battery grease and shims which I buy. (Also had the battery tested as well as the starter and all tested ok.)

So today I jack the car up. (Intended on putting in new Duralast starter) and then cleaned the battery and added the grease and shim to the positive terminal. Rather than replace the starter first I went to start the car to see if the battery fix made a difference. I turned it over for about 10 seconds and nothing. It didn't even try to fire. The starter sounded no different but the engine just wouldn't fire.

Now I've tried removing the shim and now I really can't get the terminal tight but got it tight enough and tried it and still cranks but no fire.

I'm guessing by now after trying it over and over it's flooded but I have flooded it before (starting it and shutting it off to soon) and after holding the pedal to the floor over and over and over again I've got it started. Usually at some point in the process I can hear it trying to start. Today I get nothing.

Any ideas???

RIWWP

iTrader: (2)

A) What mileage. Your post sounds suspicously like you are still on your original coils and wires. If you are, then at this point they HAVE to be completely shot. And it's not firing because you don't have a solid spark, or any spark at all.

B) You need to grab a coil tester ($10-$15 from a local parts store) and test your coils. (it replaces the plug, just pull off the plug wire from the plug, stick it on the tester, clamp the tester to a grounding point, and try to start it with someone watching the tester. If all 4 coils are firing cleanly and brightly, then it's not a fuse or coil problem.

C) Flooding is a symptom, not a problem. You most likely have flooded your engine from it spraying fuel in, but not firing. Deflooding won't fix the problem though, because the reason why it flooded in the first place still exists.

D) IF, and only IF, you actually do have 4 new plugs, 4 new plug wires, and 4 new coils ($171 + shipping from AdvanceAuto online right now, 20% savings), then the issue is probably going to be a compression issue.

Might want to check out this thread for more details regarding that, even though you are not a new owner, there are hints in your post that you don't know as much about the RX-8 as you should. https://www.rx8club.com/new-member-forum-197/new-potential-owners-start-here-202454/

RX8Soldier

iTrader: (24)

have you changed plugs AND coils? They should be changed together, as one will affect the other.
Is the new starter you piced up an upgraded starter?

If your car is manual, try pull starting it.

BTW, yes, your thread IS like every other "no start post". Read the stickies in the froum and educate yourself on the engine you have. It will save you many headachs down the road...

Harlan

iTrader: (3)

Go to your local auto parts store and replace the positive battery terminal. The stock one is complete junk.

Rock Hopper

Okay so the plot thickens. After trying and trying finally I get nothing when I turn the key even with another battery jumping it. I hook up a volt meter and my battery shows 12.6 volts with key off, key on, and still when trying to start. So, I put my original starter back on and turn the key and the car starts after a minor amount of stumbling. It would seem the used starter I bought took a crap over night.

Here's something I don't get. In reading some of the posts I have read about the slow start some are elluding to the speed of the starter having to do with how fast the car will fire. I've always thought as long as the starter engages and turns at a good speed the should fire regardless. Like when a battery is croaking and the whole process slows in other cars it seems like when they fire they start. Is the rotary that much different?

Also, I plan on doing coils and plugs today.

RIWWP

iTrader: (2)

Yes. You need compression and a good air fuel mixture to light. Obtaining the good mixture and compression in a piston engine has almost no relation to the speed of the motor. However, in a rotary, the combustion chamber is long and thin, and curved. It is also imperfect sealing so the "longer" it takes at a given point in the compression stroke, the more leaks past the seals. The faster you spin a rotary, the more compression it will make. You can run with no seals at all as long as you stay over 8,000 rpm, it's enough compression to keep the combustion occuring.


Conversely, too slow of a crank speed, and you simply don't have a good enough air/fuel mix and not good enough compression. Engine won't fire. Also remember that the rotors spin at 1/3rd of the e-shaft speed, so an ideal cranking speed of 250rpm is only 83rpm for a given rotor face. That is stalling speed even in a piston engine, but we have momentum on our side. Drop down below about 180rpm, and it won't fire at all unless you have superb compression.

Rock Hopper

RIWWP, thanks for the explanation. It makes sense. I'm gonna put new plugs, coils, and wires in next weekend and see if that makes any kind of difference. I need them anyways even if they don't fix my slow start. Then I'll go with a new starter.