Aftermarket fuel injectors ok? 2016 CX-5

[AL Cx5]

Minimum, I would replace #1 plug. For some reason it has run rich. Could be the injector stuck open or coil pack didn't fire correctly. At this point, it won't clean it's self...

Mazda does not make spark plugs. I'm going to use ngk plugs.

Try one plug and see how it looks after a few days. If it looks like the others, then you are good to go.

Good luck

 

[cdmain]

@AL Cx5. Only thing is #1 is not the one with the misfire problem according to the scan tool.

But sure I will replace and see.

 

[Lazy2.5]

I'm pretty confident you have nothing to worry about. I just changed the oil on my Mazda 6 Skyactiv 2.5 NA. It has almost 317,000km on it. It's had some slight vibration since new

 

[Lazy2.5]

@AL Cx5. Only thing is #1 is not the one with the misfire problem according to the scan tool.

But sure I will replace and see.

Definitely follow his advice with cylinder #1, and I wouldn't worry about #4.

 

[Mazdiod2]

I would be curious about what is under that tubing and black tape. These wires carry the signal from the engine to fire the coil pack, I would guess.

 

[yrwei52]

@AL Cx5 Got the plugs out and posting the pictures.

I also had stored the OEM mazda plugs that I was using until 57,000km and now have switched to NGKs . Current odo at 59000km.

Cylinder 1: looks very black compared to the others. Have not had too many misfire counts from this cylinder.
View attachment 330133

Cylinder 2:
View attachment 330134

Cylinder 3:
View attachment 330135

Cylinder 4: The one with the misfires
View attachment 330136


Comparison between OEM vs NGK


Cylinder 1: View attachment 330137

Cylinder 2:
View attachment 330138

Cylinder 3:
View attachment 330139

Cylinder 4:
View attachment 330140

I almost wanted to say your could mistakenly think #4 cylinder you mentioned having the misfires is actually is the #1 cylinder based on the spark plug condition pictured. The #1 cylinder is on the passenger side in the US, and driver side in Australia. It seems you should get higher misfire count from #1 cylinder based on the condition of the spark plug.

 

[yrwei52]

Also sending this picture showing the ignition coil wires #4. I added the black tubing because for some reason the black sheath (as seen on #3) had pulled away.

View attachment 330149

Yes it’s weird that the black protective tubing is gone on cylinder #4 coil pack wiring. The whole wiring harness would be expensive and I don’t know if it’s worth it to replace as the spark plug condition on cylinder #4 seems to be good.

May be you can swap the coil packs and spark plugs between cylinder #3 and #4 and see if the misfire counts change.

 

[yrwei52]

⋯ Mazda does not make spark plugs. I'm going to use ngk plugs.

Yes, and the NGK model number printed on the Mazda spark plug is the same too. But the price difference is significant. And there’re many people including a tuner swear the Mazda plugs are different and they did cure the misfire problem.

Spark Plugs: OEM vs Aftermarket

Hello,

I just want to share my recent experience.
Two weeks ago I started feeling a hesitation or stuttering, right after a fuel fill up on a road trip. Which at the start I thought was bad gas, which ended having a misfire. I didn’t think it was the spark plugs because they were only 1 year old NGK with only 13000km’s on them.
So I went to Mazda this morning and bought 4 new Made in Japan OEM.
The Mazda Partsman also said, due to the SkyActive High Compression engine that it’s best to use the OEM.
So long story short, it’s not worth the savings and stick OEM.

Here are what the Orangevirus Tuning (OVT) gets to say about OEM spark plugs used on SkyActiv-G’s:

Without getting into too much detail...you guys really...really..really want to use OEM plugs....

the reason is because the ECU uses the ignition coils, which measure a resistance across the OEM plug for pre-ignition, and extremely low levels of knock retard the knock sensor cannot pick up, along with that it gives the ECU individual cylinder information, the spark plugs are actually used "as a sensor."

How it works exactly is proprietary information that I am not willing to share, you want to use OEM plugs.

 

[AL Cx5]

Yes, and the NGK model number printed on the Mazda spark plug is the same too. But the price difference is significant. And there’re many people including a tuner swear the Mazda plugs are different and they did cure the misfire problem.

Spark Plugs: OEM vs Aftermarket




Here are what the Orangevirus Tuning (OVT) gets to say about OEM spark plugs used on SkyActiv-G’s:

I'm new to Mazdas. I've read othere places that NGK work just like oem. I broke a original plug using a 19mm socket. I have since bought a proper spark plug socket. I replaced this broken plug with a NGK. It runs great and exceeds published FE. With currant tune and mods is getting 36 mpg highway. So the NGK is not hurting anything on my setup.

So, pick a plug that you are most comfortable with. If you don't have the few tools needed, purchase them and change the plugs. There are YouTube videos. I swap out a plug 2 times on the side of the road when tuning to double check what the tune. Maybe a 5 min operation.

Fwiw, the sensors are averaging the combustion. Like 1 O2 sensor averages 4 cylinders. Issolating 1 cylinder give a snap shot of what's going on. The electronics don't show how well the fuel burned, if it has to much or to little timing for the plug heat range and so forth. So I put a new plug in, make a wot pull, shut down and remove, insert the original plug.

I have a few melted pistons I keep areond to remind me that the sensors don't know everything...

As I understand, #1 is on the right side of the car, facing forward. The pic shows that it's fouled.

If in doubt, change all 4 plugs.

Your repair to the engine harness looks good. If #4 is not showing a miss, it may have been a short in the harness.

 

[cdmain]

Hi all,

Thanks for the input.

#1 plug will be replaced. I have a spare plug in the garage that I bought few months ago when trying to isolate the issue on #4.

After I had taken the plugs out yesterday and reinstalled. I started the car waited for the idle to settle down , put the scan tool on and ran the Mode 6 tests and saw the misfire counts on #4 in 2 mins count was as 37 and increasing.

I also verified the cylinder order using the scan tool by unplugging the coil pack for a brief moment while engine running and observing the misfire count.


#1 is on the drivers side and #4 on the passenger side in Australia. @yrwei52 was hoping it was an error on my scan tool (Bluedriver) software but no.

I measured the spark plug resistance

NgK
#4 4.83 KOhm
#3 5.80
#2 6.04
#1 6.23

Oem
#4 3.74 KOhm
#3 4.06
#2 3.62
#1 3.81

I found a video on how to clean MAP sensor so I will do that. Not too sure how to check O2 sensors.


@ AL cx5 a short in the harness , possible, but not sure why it's more often on idle.

Regarding oem vs ngk. The only issue with ngk is that there are too many counterfeit ones on the market , it's hard to tell them apart. I bought mine from an automotive store online. The OEM's are 4 times the price. And remember the issue I have was present with the 57k OEM's too. So I don't think new OEM's would change the situation.

I'm curious , have any of you run the Mode 6 test on scan tool for mazda 2.5L NA on idle to see if this issue is common?


Next step is the compression and leak down test.

 

[cdmain]

Hi all,

So back from the compression and leak down test.

Compression
#4 140 psi
#3 135 psi
#2 125 psi
#1 125 psi

Leak test revealed #3 leaking from piston oil rings other cylinders are good. Mechanic said when oil was added to #3 it did not leak.

He also advised swapping fuel injectors to see if misfires follow and recommended using oem spark plugs. He said perhaps the injector on #1 was leaking, hence why the spark plug #1 appears fuel rich.

Looks like next steps for me will be to swap fuel injectors and renew spark plugs.

 

[AL Cx5]

Hi all,

Thanks for the input.

#1 plug will be replaced. I have a spare plug in the garage that I bought few months ago when trying to isolate the issue on #4.

After I had taken the plugs out yesterday and reinstalled. I started the car waited for the idle to settle down , put the scan tool on and ran the Mode 6 tests and saw the misfire counts on #4 in 2 mins count was as 37 and increasing.

I also verified the cylinder order using the scan tool by unplugging the coil pack for a brief moment while engine running and observing the misfire count.


#1 is on the drivers side and #4 on the passenger side in Australia. @yrwei52 was hoping it was an error on my scan tool (Bluedriver) software but no.

I measured the spark plug resistance

NgK
#4 4.83 KOhm
#3 5.80
#2 6.04
#1 6.23

Oem
#4 3.74 KOhm
#3 4.06
#2 3.62
#1 3.81

I found a video on how to clean MAP sensor so I will do that. Not too sure how to check O2 sensors.


@ AL cx5 a short in the harness , possible, but not sure why it's more often on idle.

Regarding oem vs ngk. The only issue with ngk is that there are too many counterfeit ones on the market , it's hard to tell them apart. I bought mine from an automotive store online. The OEM's are 4 times the price. And remember the issue I have was present with the 57k OEM's too. So I don't think new OEM's would change the situation.

I'm curious , have any of you run the Mode 6 test on scan tool for mazda 2.5L NA on idle to see if this issue is common?


Next step is the compression and leak down test.

I buy my NGK plugs from a reputable source. I bought the CX 5 turbo plugs from Rock Auto. No FleaBay plugs.

Maybe cleaning and flow testing all the injectors is in order. Since our O2s are averaging 4 holes, all the injectors need to flow close to the same.

O2 sensors have to be replaced. It's a little early for that. I'll change mine at 100k mi. As mentioned they loose calibration and tell the Ecu to use more fuel. I saw a nice bump in FE when replacing.

Looks like your making progress!

 

[cdmain]

@AL Cx5 Thanks for the advice.

I was doing some further reading. If you notice I have oil on my spark plug threads . When i took the spark plugs out, the car had not been driven for a few days so it does not look prominent on the photos. Any chance the misfires might be due to worn spark plugs tube gaskets?

This video shows how to replace these.

Mazda CX 5 CX 3 Mazda 3 Mazda 6 Mazda 2 Skyactiv Valve Cover & Oil Control Valve Gasket replacement

Hi guys , sharing you another video. This time i had a small issue with this Mazda CX 5 Skyactiv that is a small leak from the Oil Control Valve / VVT Soleno...

youtu.be

 

[AL Cx5]

@AL Cx5 Thanks for the advice.

I was doing some further reading. If you notice I have oil on my spark plug threads . When i took the spark plugs out, the car had not been driven for a few days so it does not look prominent on the photos. Any chance the misfires might be due to worn spark plugs tube gaskets?

This video shows how to replace these.

Mazda CX 5 CX 3 Mazda 3 Mazda 6 Mazda 2 Skyactiv Valve Cover & Oil Control Valve Gasket replacement

Hi guys , sharing you another video. This time i had a small issue with this Mazda CX 5 Skyactiv that is a small leak from the Oil Control Valve / VVT Soleno...

youtu.be

Not likely oil will seep through the threads. You would see a puff of blue smoke at start up.

It looks like it either didn't fire, coilover, or injector hung open.

 

[yrwei52]

@AL Cx5 Thanks for the advice.

I was doing some further reading. If you notice I have oil on my spark plug threads . When i took the spark plugs out, the car had not been driven for a few days so it does not look prominent on the photos. Any chance the misfires might be due to worn spark plugs tube gaskets?

This video shows how to replace these.

Mazda CX 5 CX 3 Mazda 3 Mazda 6 Mazda 2 Skyactiv Valve Cover & Oil Control Valve Gasket replacement

Hi guys , sharing you another video. This time i had a small issue with this Mazda CX 5 Skyactiv that is a small leak from the Oil Control Valve / VVT Soleno...

youtu.be

Some oil residue on the thread of spark plugs is pretty common and won’t cause any misfires because of that. Yes the oil control valve on top of the engine is very prone to leak. If yours leaks, you can change it with a new set of valve cover gasket which includes spark plug tube gaskets.

Oil on spark plugs (2015 CX-5)

Again you can swap the spark plug and ignition coil pack on #4 with any other cylinders to see if the misfire count moves.

 

[cdmain]

@AL Cx5 I have not seen blue smoke on start up so far. I will keep an eye on this.

@yrwei52 I have no evidence of oil leaking past the oil control valve gasket. So I won't bother with this valve cover repair then.

I thought it might be one of the reasons the misfire remains on #4 despite swapping plugs or coils i.e. that particular spark plug tube is more prone to oil seeping in.

Thanks again.

 

[yrwei52]

⋯ @yrwei52 I have no evidence of oil leaking past the oil control valve gasket. So I won't bother with this valve cover repair then.

The common oil leak problem is the oil control valve itself, not the OCV gasket.

I thought it might be one of the reasons the misfire remains on #4 despite swapping plugs or coils i.e. that particular spark plug tube is more prone to oil seeping in.

So you have swapped the ignition coil pack on cylinder #4 with other cylinder’s and the high misfire count didn’t follow?

 

[cdmain]

@yrwei52 ok I did not know about the oil control valve leak problem . What does this valve do?

Yes the high misfire count stays on cylinder 4 despite swapping coil and spark plug. Will need to swap fuel injector next but since that is more difficult ( i have never done this before) I was looking to see it there is any other potential causes I could eliminate. When I saw oil on the #4 spark plug threads I thought perhaps the oil was causing the intermittent misfires on #4.

 

[yrwei52]

@yrwei52 ok I did not know about the oil control valve leak problem . What does this valve do?

Oil control valve OCV is operated by PCM and controls the hydraulic oil passages to the hydraulic variable valve timing actuator for variable exhaust valve timing.

 

[cdmain]

@yrwei52 Thank you for that information.