Won't start after replacing coils.. flooded? or battery issue..
 

Hi all

Before you flame me for asking something that can be searched on the forums please hear me out!

A great thread on this subject is here, which I've read:
https://www.rx8club.com/series-i-tro...l-swap-242880/

Please let me explain my situation-

Wednesday evening on a routine trip I was driving home for approx 10-15 minutes at which point the CEL comes on and starts flashing. As I slow down to pull over the engine stalls. I give it a moment and try to fire it up - with no problems at all - plus no CEL light anymore.

Thursday evening my girlfriend starts it up with no problems and we go to dive up the street. The engine seriously struggles and I told her that it's in 3rd gear (as it had no power) and she's not familiar with the car. She then put it in first and it went fine to the end of the street. 20 seconds later the same thing happened again, I told her it's in 3rd judging by the lack of power and she said it wasn't - sure enough, it was in 1st but the engine was not generating much power. We pulled over and the CEL light was flashing; revving it slightly in neutral gave the feeling a cylinder was down and so I limped it back to home and parked it.

I read the CEL code as P0203 (cylinder#2 misfiring) and so on the weekend I pulled out spark plug number #2 and it was a bit black but relatively fine. I cleaned it up, put it back in and started the car - it started fine but had the same issue as before.

** Now this may be the problem: I only had the car running for 15-20 seconds or less before trying to hold it at 3,000RPM very briefly before turning off the key. I didn't want to keep it running with a cylinder down as you can imagine...

The plugs were replaced by Mazda as part of a service 1 month ago.. so I checked the wires, all seemed good and so I assumed it's got to be the coils.

I order new coils & fitted them today. I tried to fire it up with no luck - it would turn over fine but not fire up. I double checked the wiring (everything was marked) but all was correct except for cylinder#4 lead being a bit loose so I sorted that out (separate story - bad coils, see photo at the bottom).

**At this point I noticed that the positive terminal on the battery was very loose! As part of the repairs earlier I had taken off the negative terminal but not touched the positive terminal.

I then tried the de-flooding procedure but only for approx 60 seconds as I didn't/don't have another car that I can set up with jumper leads at the moment.

Questions-
* could a loose positive battery terminal give the symptoms originally faced where by it was misfiring or would the alternator realistically be powering the coils after the car started?
* is there a clear way to define if it has ignition issues or if it's flooded? on the other similar thread there are two video's, it definitely sounds like the flooded version.

Thanks in advance

You flooded the engine, and just haven't finished deflooding it yet. You solved the problem for why it flooded in the first place (coil failure and battery terminal loose), but you still have to deflood.


I'd recommend testing the wires with a multimeter to see if they really are "fine" or not, they degrade internally over time. You can spot corrosion on the tips, but you can't visually inspect the internal integrity. Degrading wires will re-kill the plugs and coils quicker than the prior set.

(and that code would be P0302, a typo on that i expect)

I'm sure I posted back on this thread with a thank you, but apparently I didn't.

I've been away for 3 weeks and just thought I'd try the car again today - no luck as expected. I borrowed a running car to hook jumper leads to and tried the deflooding procedure here:
https://www.rx8club.com/series-i-do-...lumber-182410/

Unfortunately after reconnecting the fuel pump and trying again nothing happened - there was no change in the engine cranking sound and no attempt of it trying to start. It sounds like an immobiliser is fitted or equivalent as it doesn't make any notable attempt to combust and thus start.

I thinking about looking at the new coils again, double check they're exactly the same as originals and maybe re-fit the old one that I know are not working - at least it started then. Its unlikely that all 4 new coils have issues so it points to flooding again but despite following the steps 4 to 7 again with no change between having the fuel pump connected or not.

Any suggestions? Without being able to confirm Air / Fuel / Spark I might have to get it towed to my local Mazda branch (45 min away).

Cheers
Keegs

Try pulling the plugs to see if its really deflooding. I thought I had mine but it wouldn't start. Pulled the plugs again and they were covered in gas oil carbon mix

So it turns out that it was just really flooded. I saw some posts referenced push/pull starts as an alternative so I thought I'd try this on a street with an incline etc.

The short version of the story is that after numerous failed attempts we needed to tow it at 15mph and drop it in second for around 10 full seconds (!!) before it would respond to the accelerator. The plume of fuel smoke was huge, approx 5m x 5m of thick smoke- fairly embarrassing! The whole street was covered.

Thanks for your help / reading.

Good to hear it worked for you. I just with I didn't have an automatic

Next time, hopefully there isn't, but next time it floods and you get it running even if its rough just let it idle for a few minutes. It will sort itself as long as your engine is in good health. After a few minutes rev it a bit and clear out any excess. I have deflooded a lot of rotaries and have never had to do anything else once if got started. Even ones on there last leg will still unflood and run, you just have to let them idle for a bit and warm up longer.