About a week ago I took my rx8 on some dirt trails to have some fun with my buddies (2004 6MT 94k miles, CAI, Catless midpipe and catback.) I have done this many many times before without any issues but this time was different. At one point down the trail there was a big mud puddle and of course I went around it as much as i can but mud still splashed everywhere because the right side of my car still went through the muddy water. I didnt notice any issues until about 20-30 minutes later when i felt a bit of power loss and the throttle seemed to have some sort of delay when starting from idle. I don't think it was overheating because I wasn't constantly bashing on it and I've never overheated. I have an AEM CAI so i was thinking maybe some water and debris got in the intake and that it would maybe flush or burn out. So the car drives the same way all the way home and then I turn it off. When i tried to turn it back on it just cranked over and over but after about 10 seconds it sputtered to life. My car had good compression 100% before this and I have never had a single problem starting it until this day. I was concerned and drove it around the block to get a feel of what was wrong. I drove it back home and searched for hours on the forums for an explanation to the many symptoms I've been having but no luck. The next day I tried to start it but it wouldn't start so at this point I was pretty sure it flooded. I replaced the ignition coils because 2 of them seemed to have been affected by the mud and had weird corrosion on them. I cleaned the whole engine bay, the ess with a rag, and the whole intake including the maf sensor. Went through the whole deflooding process, having to crank it 13 times instead of the 6-8 times most members say it takes. It started up and I went for a drive, the throttle delay problem seemed to go away about 95% and the power loss was still there but seemed to have improved. There is minor hesitation through 6k-7krpms. It threw 2 codes that werent there before the offroading- p0302 rotor 2 misfire and p0103 high input maf signal. Every time i turn the car on, I have to push the gas pedal to the floor and crank it for 10 seconds and then wait and then crank it when slowly releasing off the gas pedal then it sputters to life. When it is warm, I usually can just start it and it slowly sputters to life but when its cold i 110% have to do this.There is rarely any apparent misfires and besides the power loss and hesitation, it drives fine. Ive limped it around town for about 2 days and I am going to replace the spark plugs and clean the maf again today. Can anyone help in any way possible to diagnose this thing because i cant get my head wrapped around it.....

 

Have you done a compression test since the mud incident? Water into the combustion chamber can cause damage. Possible you could have blown a water seal which is why it’s showing symptoms of flooding. Compression and block test would be recommended to make sure the engine isn’t damaged. If it checks out, I would say test all ignition system components from the plugs, wires and coils.

 

I don't have the time or money to do any of those tests right now. Are there any diy tests you can do? To atleast get some sort of idea? The car doesn't overheat even when im sitting in traffic. The car doesn't blow white smoke even right after i start it. So i feel like a water seal isnt damaged. Im thinking maybe the fuel injectors got messed up somehow or maybe some sort of electrical issue with the ignition system because i replaced the whole ignition system about 7k miles ago (OEM parts). It doesn't get horrible gas mileage either, drives the exact same as before when cruising. The startup is the main thing that concerns me. If the new spark plugs don't improve anything then Im replacing the ess, then the starter because I don't think it has the updated new one. It's never needed it until now.....oh and I will probably get a new maf sensor because cleaning it again did not fix the CEL code for it.

 

If you don't have money for tests you definitely don't have money for randomly replacing parts. Slow down. Replacing coils is a good idea, they may have gotten wet. Not just the 2 weird ones. Test them properly. You may also have cracked a spark plug.

What did you clean the MAF with? They're very sensitive and require a special MAG cleaner. Brake cleaner will destroy them, and other cleaners will make them read wrong.

Possible it's just your battery and/or grounds? Poor battery will cause the starter to turn slower

 

Loki is right. Right now you are just speculating without actually investigating. Throwing parts at a car is a good way to throw your money away.

What do your spark plugs look like? And for coils, it's recommended to replace them as a set. If two of them fails, the other twos probably also have a foot in the grave already. You could grab an ignition timing tester from any auto shop to check them.

Report back when you have the spark plugs out.

 

The grounds on the battery are pretty clean and when driving it stays above 14v 99.9% of the time. I did replace the ignition coils as a whole set. i cleaned the MAF with MAF cleaner and was very careful about it, even watching multiple videos on it just to make sure i wasnt doing anything wrong. Im just very jumpy on buying parts because this is my first car as a 17 year old high school student (had the car for over a year) and this problem is so specific and doesn't have one obvious answer. I also need this car to reliably start before school starts up again in a week. So im in a bit of a rush. Today only 1 spark plug came in the mail(?) even tho i ordered all 4 at the same time....so when i get the rest i'll let you guys know the condition of the ones in the car atm.

 

The ess could be somthing to replace/clean. Also when this is fixed I suggest not going offroad in a sports car lol.

 

Battery voltage isn't the same as it's capacity to turn the starter. If you can get it to an autozone or similar, they can perform a load test, usually they're free. My logic here is that hard starting is due to 1 or more of the following: starter speed too low, poor ignition, poor fuel mix or poor compression. Compression would get worse with warm starts, so it doesn't sound like that. You have/are addressing ignition. Fuel mix would be bad across the entire operating range, so it's not that. That leaves the starter, which needs a good healthy battery and clean and tight connections all the way through. And obviously the starter itself could have failed. They slow down with age. Your starting speed needs to be 250rpm+. If you have a bluetooth OBD adapter you can check the cranking speed (and other parameters) easily to confirm. If it's the original 04 starter, plan to replace it with a 2kW one anyway.

 

As was said before, you will need to test and clean up your ignition system. Misfires are generally caused by bad ignition systems or clogged cats. In your case it does sound like your ignition components may have been ruined.

You wont see white smoke except for on startup then it will go away, that's a coolant leak in the engine block. This is why testing is important so you aren't wasting your money switching out parts that may or may not fix the problem. You are just guessing, I prefer to know for sure.

 

I know im getting crap for just buying parts like crazy without doing a bunch of testing but id rather spend $100 on a part that could potentially fix my car then spending money on testing and not have money left for fixing. So im just gonna read forums and use logic and connect all the dots that i possibly can to come to a solution. (probably not the most efficent way to go about this and im sorry)

Replacing spark plugs and wires when the last one comes in the mail... (only one plug has come in each day and i have absolutely no idea why)

The cranking speed started at 250rpm on the dot but then slowed down every second and after a few seconds got to the 230s. Would that be a weak starter or crappy battery?

Either way I bought a 2kw starter because on all the forums ive read, people have talked about their drastic improvements on startups with it and thought it would be a good idea.

Have not tested the battery yet due to not having much time the past few days.

Also i just realized no one ever addressed my throttle delay issue. I bring this back up because today when I took the car out it seemed more noticeable? When the rpms are around 900 at idle at a stop light, I just cruise off as normal and everythings fine. But if the idle is around 750ish and I blip the throttle to start moving...sometimes the rpms drop to around 500 before rising up as usual or sometimes it will kind of stutter? Ive read this could have something to do with the maf or vacuum lines. Could the CEL about my maf sensor be the reason for this? And since my maf sensor is causing that CEL even after cleaning it, should i replace it or is there some fix for that? The maf sensor reads 6-7 g/s at idle and anywhere from 200-260 g/s at WOT. Could it possibly be a gunked up throttle body?

I dont know why i would have any carbon buildup because i rip my car around almost all the time but earlier I did some highway pulls to clear out the engine of any carbon deposits. (another possible solution that i thought i would give a try) Days ago I had that hesitation issue at 7k rpm but after today, it seemed to almost completely go away? Weird but still doesn't solve any of my other issues.

The car drives like is just has a barely sub-par ignition system but the flooding is just so bizarre.... and as far as i know i have never seen anyone have this issue. What could be causing it to flood itself EVERYTIME i turn it off, even tho the car is completely warm when i shut it off?

 

6-7 g/sec at what rpm? It sounds high for a warm idle. What's your intake like? Are there any open/unconnected hoses?

 

6-7 g/s at around 800-900. Ive seen it read 5g/s but its 6 most of the time because the idle usually fluctuates a tiny bit and sits normally around the 800 mark.

Its just an AEM style intake, all hoses are connected (as far as i can tell). The hoses also are in good enough shape so i dont think they have any cracks or holes. Ive been using the intake for a year and havent had a single problem until the one dreadful dirt trail day ive talked about.

 

Most of the resources you need for diagnosis is either free or not expensive. $100 can net you a ton of tools. Grab a service manual(free PDF version is available on the forum) and read up. It shows what a Mazda technician is supposed to do when solving the problem. Even if it is expensive, it's something you want sticking around for a long time like a quality wireless OBD2 reader.

Theory is also not like practice. You need to do some proper troubleshooting on your own. Because one guy threw a part at something and fixed it, doesn't guarantee it will happen to you.

You can ask a shop to perform a load test on the battery for you for free. They want to sell you a new battery so they'd be happy to do a test for you.

A gunked up throttle body can be checked pretty easily. Remove the airbox and the accordion tube and there it is.

Some of the intake valves(SSV, VDI, etc.) can be gunked up if you don't drive hard often enough. Carbon deposit in the engine, however, is inevitable unless you have a water/meth injection kit installed.

 

Ok have the same exact response problem only while sitting at a stop like you said. Its a pita when on a hill at a light. I have a shutter control valve stuck open code. I'm pretty sure that's the cause. I can't recall the actual code right now. Down side is you have to pull motor to get the lim off. The APV is closed when at idle and opens at 6250rpm for more air. If it's stuck open then it gets to much air at idle and causes the throttle delay or idle search.

 

Red Line - I know you can remove, clean & replace the SSV w/out removing the LIM. Not difficult...I've done it. I presume you can do the same for your APV, if necessary. Confirm which needs to be done, then check the forum.

 

The auxiliary port valves cannot be removed from the lower intake manifold with the engine still in the car. If you wish to clean them, you have to remove the engine and then the lower intake manifold and once you have the manifold on the bench you can clean the auxiliary port valves.

 

I already know this and I'm doing it in the spring. I was just mentioning this because the op seems to have the same symptoms

 

So I got some clips of the car starting. The cold start in the video was a pretty slow relative to most of the cold starts I do. Everything was frozen over last night. The hot start was pretty quick and I recorded that 30 seconds after shutting the car off in my driveway.

I have upgraded the starter and I replaced the whole ignition system. The car has not once ever failed to start after doing these repairs. Just takes FOREVER.

Cold Start:
Yes I know I kept it cranking both times for 20 seconds but I think it's fine

Hot Start:


The CEL flashes when trying to start it cold. So if it is in fact misfiring, what about it being cold would make the car misfire??

The car drives almost perfect, extremely smooth. Just has the slightest lack of power in higher rpms (feels that way but I'm not sure if that's just my brain tricking me or not). It idles fine, it's never jumpy unless the A/C is on (very minimal idle jumps but thats always been that way).

Could the coils had been bad right out of the box maybe? I didn't get expensive ones but they are the same ones that I bought 10k miles ago and I never had a problem with them before...
Even with bad coils I feel like this thing would start in less than 40 seconds of straight cranking!! Even if they are not 100% up to par, they can't be that horrible because the car drives so well for how bad the starts are.

I would say its just bad compression, but by the way it drives, the fact it starts better when hot, the fact it doesn't blow smoke clouds of smoke of any color, the fact it idles perfect and doesn't stall out of nowhere....there's just no way this thing has bad compression. The only symptom of bad compression that it has is "hard starts" in general. So something else just has to be wrong.

If anything seems fishy or unusual from the videos, please say something. If anyone has any ideas at all, it would be greatly appreciated...

 

It doesn't even sound good starting up hot. Sounds like one of your rotors is missing and has low compression. I suspect internal seal damage. The pulses sounds off you may have a bad seal. I would recommend a compression test to be sure but it's not sounding promising. Unlikely it's the coils. Cheaper coils just have a shorter lifespan, they still work fine.

Edit: normal for the CEL to flash with just acc on. Only a misfire if it does it while engine is running. Here is how a healthy engine should sound while cranking.

https://youtu.be/U02w9407hXQ

 

Ill be getting a compression test in the near future. I've done so much damn research and I am just tired of speculating. Things dont add up tho and thats where I'm left scratching my head.....

If I had bad compression then it should be extremely hard to start when hot, right? The hot starts I'm having are similar to an engine with low compression, but the car is 5x harder to start when cold (which makes zero sense). I also don't misfire whatsoever when redlining or ripping it around town. I've even tried to get it to hicup and misfire but it hasn't done it once after new plugs.

Also how could my car run fine but start so badly? I've seen people with bad compression engines start way faster than mine and their cars run like crap or die at idle. I just feel like there's something I'm overlooking or completely missing.

 

It depends what kind of seal went. There are different kinds of seal failure and each has different effects on the engine. I can just listen to the pulses and something sounds off about the way your engine cranks. Won’t know for sure until you test compression however. If you even have a regular compression tester, it would be quite easy to notice if there was a seal gone. You would get two good pulses and one bad one, probably just on one of the rotors.

 

When you hold the gas pedal down all the way during startup you're actually cutting all fuel. What you're doing is actually the deflooding procedure.

Is your coolant level going down? Is there coolant on the spark plugs? Because this all sounds like a water seal. Water seeps in while the car is sitting, making a hard cold start.

 

Those are the spark plugs that I pulled out after deflooding the car. One of the plugs in rotor one was pretty oily when I took it out. Don’t remember if it was leading or trailing but Im 80% it was trailing.There are new ones in the car.

When I start my car, theres just the usual grey light smoke coming from the exhaust and after 20 seconds it’s pretty much gone. If it was a water seal that went bad, wouldn’t it be blowing blue or white smoke clouds out the back? Especially on cold starts?

Also I’ve never flushed the coolant or anything in the car. I check the coolant temps through my Bluetooth obd2 reader and it doesn’t overheat.

 

The two top pics are the leading plugs. Bottom two pics are your trailing. Important not to mix that up when installing. Trailing plugs go on top, leading plugs go on bottom. Easy way to remember is T = Top L = Lower.

They dont look too terrible. Definitely running rich if anything. Absolutely worth changing out. You should perform a coolant change and ensure it's running Mazda FL-22 coolant. If you have a coolant seal breach in the engine, it would be a white smoke. Your main concern is doing a compression test to rule out engine damage. Otherwise you are just wasting your time and money replacing parts hoping it will fix it.