Cranking but not firing - Ignition or Engine?
 

I doubt this is a "flooded" issue since I haven't had that since the new engine (which is only ~10k miles on it) and was driving the car, both times it happened today, for > 30 minutes.

I would pull into a place, turn it off, run in and out (~5-10 minutes) and it wouldn't start up.

Has a brand new battery and I can hear the start cranking fine. Just seems like nothing is firing (as if it is flooded). Car is at 112k, engine was replaced ~10k miles ago and replaced coils and plugs when I got the car (98k miles).

Is it time for a new ignition system (I hope that is the only cause of issue right now). Could this have been a problem due to the car continuously having to get jumped / dying (battery was old) and the fact I hardly drove it during the winter time this year?

Reason I think it isn't a flooding issue is because, and it might be a "hot start" issue is because of the fact I drove it for so long and eventually, after waiting a while, the car would crank over.

Could be so many things......when it runs does it run well?



The only real way to rule out the engine thing is to get a compression test..

Yes, it does. No rough idling or random kills, I get the power when I give it. So, that is why part of me thinks it might be more ignition and not so much the engine?

BUMP; anyone any thoughts? Should I go ahead and get the BHR ignition kit? Is it worth getting he plugs from them as well? Any other things to go test out?

I kind of don't want to drop ~$200 for a compression test on an engine with only ~10k on it (which was a rebuilt from Mazda and installed by Mazda)

I think there is a rotary shop in your area that should be able to test it for much cheaper.

Any names or links? It would be awesome to get a proper rotary shop verse just Mazda dealers.

Also, when I "crank" let it be known it does not sound like it is firing. The sound is directly like the starter just spinning. On occasion it will attempt to fire for total of 1 second / cycle and than go back to just the starter.

Sometimes, it is strictly the starter (the engine is not sparking at all). That is why I felt it was my ignition system or does this sound like something more?

https://www.rx8club.com/mw-rx-8-foru...hicago-204055/

By "not firing" do you mean "not combusting" or "there is no spark"? You can hear the former, you can't hear the latter, but the term usually means the latter.

You can always get a spark tester and test at each plug to see if you are or are not getting any spark. It is possible it's something as trivial as a cracked spark plug or busted boot, or something. We see spark plug failures reported on here several times a year (usually either extreme age or someone over-torqued them), so it does happen.

The only sounds I hear are of the starter cranking (which I am almost positive, the RPM's are not moving) meaning that the engine is not turning / there is no combustion happening? But when that (1-2 second burst happens on random) it will bump the RPM gauge but die.

Spark plug tester might be a smart thing for me to do as well. When I got the car, I had replaced only the coils and spark plugs - could the wires be bad?

Yes, wires can fail :)

Bad wires means that the good coils can't get the juice to the good plugs, leading to coil burnout and plug fouling.

If you REALLY want to see if the engine is turning or not, have someone else crank the engine while you look down at the front main pulley to see if it's turning (i suspect it is, no reason to believe it's not)

If it is turning, is that pointing more towards low compression / engine problems or the ignition system?

It just means it is turning ;)

You need to check the coils/wires with sparkplug type ignition tester.....if you have spark....check fuel....If you have both then you likely need to deflood it

The reason I find the engine "flooding" as not the case is because I had driven it multiple times that day, for at least 30 mins times. Only for it to not start up after turning off in-between those times. Would the engine still be flooding at that point?

And if the engine is flooding, wouldn't that point to bad ignition system anyways? I'll be sure to get a spark plug ignition tester to see what is going on.

EDIT: Any links to good spark plug testers or the actual thing I need to buy to do this?

This is the one I bought from Orielly's which is so worth its weight in gold.
Lisle 20610 - Spark Tester | O'Reilly Auto Parts

Get yourself a remote starter and you're good to go. Saves loads of time getting in an out and helps you see the spark tester above in better view.
Innova 3630 - Remote Starter Switch | O'Reilly Auto Parts

Thanks for the links! I'll be sure to at least get the spark plug tester. That should be able to tell me that my ignition system is strong or just that my coils / plugs are fine?

Also, the remote starter probably will not work for me (as I have a manual car)?

It's an inline tester so you can put it on the coil then to normal wire to test coil. Then you can put it inline from the wire to the plug to test the wire.

As for the remote starter, it works on manual and automatics. It simply connects to the starter. You put your car in neutral or out of gear, keep the emergency break on. Turn the key in on position only. Then while you are outside looking under hood, you squeeze the trigger to turn the starter. This will basically make your task a one man job so that you are not inside the vehicle trying trying to turn key and hold clutch while trying to see the tester light up.

With the tester, you want to also check for consistency and pattern. Example, constantly firing or is it random, or weak. You will notice when you test out different setups.

Awesome, bought that stuff an Amazon (was cheaper and I have Prime anyways) so hopefully this weekend I can get some testing done.

Took it into a shop. They say my ECU is pretty much failing so they are going to replace it (putting in a Used ECU is fine right??)

Also, they said the crank shaft sensor is going to die eventually, so asked if they should replace it - I said yea.

Would the ECU be the cause to the starter going but the engine not working? The shop also said they noticed the "lack of turning on" when cold as well. They said they could get it to start but had to play with the keys a lot.

BUMP:

So, the mechanic I took it too, said he got a used ECU and tried to "program it" but could not on a rotary engine (weird). He also said he took it to another guy to try to program it but he couldn't either (are these really that hard to "program?"). He finally said he could bring in a guy who might be able to, but that guy's rates are $180/hr and there was no guarantee.

I said forget it, i'll come on here and find what to do next.

SO, WITH THAT SAID.

Does anyone know what I should do to replace my ECU and what shop in Chicagoland area to take it to?! I really do not want to go to a dealership.

There are only 2 ways that I have ever heard of an RX-8's ECU failing:

- Someone connected their battery up backwards
- An alternator failure over-volted the entire car and fried everything.


Since there is no indication you have done either ... I feel safe saying that it's not your ECU. You are literally wasting money, and the people you are throwing money at have no idea what they are doing.


If you are determined to replace the ECU however, only a dealer will be able to program it correctly. Every electronics module in the car is looking for the ECU that is currently in it, and every module has to be updated to work with the new ECU. It's not going to be cheap. It's also not going to solve the problem.

Well thank you for getting back to me. That makes sense and that is why I was a bit confused.

Now, I was never able to test my ignition system. The reason being, was I bought the tools listed but a few things stumped me:

1) The tool I have, I could not figure out how to get wire it between anything. It wouldn't fit when I tried to hook it into the coil! (the intake is in the way?) Do I have to take the intake off to test the coil? I think I might just go ahead and get the BHR ignition kit (The coils / plugs have about ~15k on them, the wires I had never replaced).

Maybe just replacing the wires is a good idea anyways?

2) Where do I hook up the manual starter tool to?! I was baffled when looking under my car and looked for answers online with little help. Does anyone have a diagram, description or pictures of where to hook the starter tool up to?

Also, anyone have any idea about how to test the fuel pump to see if that's the problem and if it gets heat soaked?

EDIT: Also, the ECU isn't fried or completely dead, he mentioned he was getting bad readings from it and figured it to be the ECU was bad? Or something like that.

Can you post pictures of each of the tools you are referring to? Or perhaps link to a picture of each online.

Bought those, just off amazon:

I've never used the first one, but the instructions say to connect it between the starter B+ solenoid and a grounding point, and pulling the trigger will provide power to the starter. Perhaps Clubugly will give you the information on where exactly to hook it up. Personally, I just recommend getting someone else to crank the engine for you.

The 2nd one is an in-line spark tester, the plug wire plugs over the end near the light and the other end of the tool plugs onto the sparkplug. So you have the coil current passing down the plug wire to the tool, through the light, and then to the spark plug. You would test each wire/plug in sequence to see if there are any that aren't firing consistently.

Since you are trying to get it started in the first place, keep in mind that only the leading plugs (lower) fire during starting. The trailing (top) plugs won't be firing, and that is normal. So it's only worth testing the lower set.


But the direction is correct. You need to verify fuel, and verify spark. If you aren't getting either, it's the e-shaft sensor that has a problem.

If you are getting fuel but not spark, it's an ignition failure or engine block grounding failure.

If you are getting spark but not fuel, it's a fuel pump failure

If you are getting both spark and fuel, then it is a problem with either low cranking speed, compression loss, or a drowned spark (flooded).

Thank you for all of that info. I will be going and working on it this weekend in hopes of fixing it.

The mechanic also mentioned that he found low voltage coming out of the crank shaft sensor - it wasn't failed yet, but could soon. Could this be a cause of anything I should look into replacing?

I don't know what "low voltage" means, since it is a 0v-5v signal... so it would be "low" normally. The proper test is a resistance test, not a voltage test.

Another sign that the guy really doesn't know what he is doing.