Cracking and popping sound when accelerating

[MazSpeed3]

Need Help !!! 07 MS3 51K
1 - Cobb A/P Stage 2 93 Oct V108
2 - Cobb Intake
3 - Cobb Downpipe
4 - Corksport Cat Back
5 - Denso 1 Step colder Plugs ( But changed back to factory)
6 - Forge BOV

First the CEL was blinking then stayed on ( Multiple Misfire ) Cleared it
Second CEL light steady ( Cyl 3 misfire ) put new Denso's 1 step colder plugs

Now when accelerating hearing a cracking and popping noise. Put back factory plugs

On the AP my Knock Retard goes up to 8.1

Had the car on a lift and going through the gears and no cracking or popping sound.
When in neutral and rev the engine no cracking or popping noise. Only when driving at 3500 RPM or higher.

Can someone please help me as to what it could be ?

Thank!!!!

 

[MazSpeed3]

Any thought or suggestions ???

 

[MSMS3]

Where are you? What is ambient temperature there. You are getting the misfire under load. You can't repeat the same conditions by just revving the engine, even with the front wheels spinning in various gears. You have to put the power down to the road surface against load.

What is the gap on you plugs and are they clean? With AP you should have those plugs gapped down to .028 or maybe even as tight as .026 with stage 2 maps.

Has the car been running well on your stage 2 map and if so, for how long. What octane fuel is in your tank right now? I think engine is pulling timing and you are getting a misfire. Start by answering questions above. I'm sure others will chime in with more suggestions.

 

[eg6motion]

Sounds like you are getting severe knock. Time to get it tuned.

 

[MazSpeed3]

I live NY/NJ where the Temp avg. out around 25 degrees. I hear the cracking popping sound under engine load.

The Denso's are gapped at .28 ( CoBB suggested ) Occasionally get CEL Code P0421 but was eliminated with Cobb AP update from V 107 to V 108. 93 Octane from Sunoco.

Running Stage2 93 V108 from Cobb AP

Thanks MSMS

Do I just need a tune ? eg6motion

 

[MSMS3]

So, your plugs are clean and properly gapped. Spark is good. But you are now back on stock 51K miles plugs? Maybe not so good spark. You are running 93 octane fuel. Did you get bad gas? Also, winter fuels are compounded differently that summer gas and this can affect your tune if you are close to the line. You are running a Stage 2 OTS 93 octane map in sub freezing weather. You're getting knock retard showing up on your monitoring, but you are not getting the hard, slap you down, forceful bump of load cut, I gather.

One thing we have not considered is that BOV. I'm assuming it is a BPV and that it's plumbed to full recirc and is properly adjusted. It is unlikely that it is messing up, but one way to tell is to put the stock bpv back on and compare.

It is starting to look like that OTS map may need to be "tweaked" a bit. You'll have to get AP experts on here to tell you if the map you chose is right for your particular combo of mods. If it's the map, one way to know for sure is to flash it back to stock temporarily and see if the miss goes away.

 

[SallySpeed3]

Have you considered back-fire? Lately when I'm close to or at WOT, shifting into 3rd or 4th gear I'll get a huge "pop" sound that sounds like it's coming from right below me. I'm pretty sure its a back-fire when it happens.

 

[MazSpeed3]

I put the OEM BOV back on and reflashed the ECU to stock and still makes the sound. It sounds only at WOT like stepping on bubble wrap or shaking a bag of marbles.

 

[MSMS3]

Someone is going to have to ride with you when it is making that sound. Someone who has some diagnostic skill. Those sounds you are describing just don't match with descriptions I'm familiar with. I know that's what you hear, but maybe someone else might be able to describe them in a different way.

Another question: Where in the rpm band are you when you hear these sounds? I know you say WOT, but that could WOT at 3,500 rpm or WOT at 6,000 rpm. Where in the band they come in and how long they last could be important.

Are you still getting the CEL for Cylinder 3 misfire? Maybe you have a bad coil pack on cylinder 3. This is the end of the spark plug wire that connects to the plug. You could try swapping it with another one for a different cylinder and see of it throws the CEL for that cylinder. If the coil is bad, I think, I said I THINK it is actually the same part as on the N/A 2.3L engine and that they are probably going to be in the range of $60-80 per individual cylinder coil. There is also a way to stretch the spring inside to try to get better contact, if you are sure that that's the problem after you swap it to another cylinder to see if that cylinder misfires. Otherwise, save your money and keep searching for the problem.

 

[H3br3w_Ham3r]

Need Help !!! 07 MS3 51K
1 - Cobb A/P Stage 2 93 Oct V108
2 - Cobb Intake
3 - Cobb Downpipe
4 - Corksport Cat Back
5 - Denso 1 Step colder Plugs ( But changed back to factory)
6 - Forge BOV

First the CEL was blinking then stayed on ( Multiple Misfire ) Cleared it
Second CEL light steady ( Cyl 3 misfire ) put new Denso's 1 step colder plugs

Now when accelerating hearing a cracking and popping noise. Put back factory plugs

On the AP my Knock Retard goes up to 8.1

Had the car on a lift and going through the gears and no cracking or popping sound.
When in neutral and rev the engine no cracking or popping noise. Only when driving at 3500 RPM or higher.

Can someone please help me as to what it could be ?

Thank!!!!

Your injectors have backed out of their seats....You're describing exactly what happened to me with the popping noises. It was hard to hear and my friend noticed it before I did. My car was making too much boost and pushed the injectors right out of the top of the motor. The car wasn't really noticeably slower until I tried to pull on my friend and it didn't pull past him as fast as it should. Mazda says this happens occasionally to this motor. They were surprised that three blew out on mine though haha. They knew I had parts on the car but I had taken them all off before going into the dealer which was a pain since I had a downpipe, intake and inlet, spark plugs, boost tubes, AP, BPV, ect. I paid to have the downpipe taken off but it was worth it since I would've paid for the repair otherwise.

I suggest taking it all off and taking it in if you are still under warranty. The work will be worth the savings. The bill will come out over 1k at least since the direct injectors aren't cheap and opening up the motor costs a pretty penny.

Tough luck man. I know how it feels.

 

[MSMS3]

HH may be right, but it costs nothing to tell us if you are still getting the CEL code for misfire on cylinder 3 and whether swapping the coils produces the CEL code on a different cylinder where that coil was moved to. Replacing a coil pack for one cylinder is way, way cheaper than HH's solution, if that's all it is.

 

[the_caruch]

You need a fuel pump to run the new Stage 2 maps from Cobb. Might be injector seals.

Go take a log of it when it pops and post it up

 

[MSMS3]

He's getting the same issue after flashing back to stock tune, so fuel pump may not be the issue.

Could be injector(s) seals, and if so, the damage is done regardless of what map he now runs.

A data log would be helpful, and knowing what CEL's, if any, he is now getting would be helpful too.

 

[the_caruch]

He's getting the same issue after flashing back to stock tune, so fuel pump may not be the issue.

Could be injector(s) seals, and if so, the damage is done regardless of what map he now runs.

A data log would be helpful, and knowing what CEL's, if any, he is now getting would be helpful too.

His pump could also be failing with the stock tune. He has enough mods to be in the "common area" where most pumps tend to get maxed out.

What we really need here are some logs to rule things out.

Also, a good video would be helpful if possible

 

[H3br3w_Ham3r]

His pump could also be failing with the stock tune. He has enough mods to be in the "common area" where most pumps tend to get maxed out.

What we really need here are some logs to rule things out.

Also, a good video would be helpful if possible

I would agree with you but a lack of fuel you would probably feel the difference in power and it might stutter a lot at WOT would't it? When it happened to me it was slower but there were no stutters and it drove normal until WOT when it made the popping noise. I had just been acclimated, since the difference was small, to the speed until my friend heard the noise. We even strapped it to the dyno and took a stethoscope to it and it sounded like the timing chain was breaking into a million pieces. The noise is much worse than the actual issue..... Even though it is very expensive to fix.

Also what we determined is that the knock sensor was registering so high because it was hearing the noise produced by the injectors and not by actual knock so the 8.1 you saw is not that dangerous. However, I would drive it conservatively for now.

 

[the_caruch]

I would agree with you but a lack of fuel you would probably feel the difference in power and it might stutter a lot at WOT would't it? When it happened to me it was slower but there were no stutters and it drove normal until WOT when it made the popping noise. I had just been acclimated, since the difference was small, to the speed until my friend heard the noise. We even strapped it to the dyno and took a stethoscope to it and it sounded like the timing chain was breaking into a million pieces. The noise is much worse than the actual issue..... Even though it is very expensive to fix.

Also what we determined is that the knock sensor was registering so high because it was hearing the noise produced by the injectors and not by actual knock so the 8.1 you saw is not that dangerous. However, I would drive it conservatively for now.

yea you might feel a lack in power. i would suspect stuttering at high rpm's to be spark blowout.

OP should check his spark plug gap. He may have gapped them correctly to begin with but it may have changed since then.

again, logs logs logs

 

[MSMS3]

OP bailed out on the thread three days ago. Don't know what he has done, what changes he made and certainly don't have any more feedback or data logs. Hummm . . hard to help without info.