Possible Spark Plug Issue Now?

[aruth55]

I am running a C39 Hybrid Turbo with a Tial MVS external wastegate set up with a screamer pipe. We have been having trouble hitting boost, and so we got a boost leak test. Sure enough, Dv+ was leaking as well as slightly out the dump. We replaced with a new Dv+ and new wastegate diaphragm. After that we still were not hitting correct boost though, car was more responsive and such but still not peak. We have not gotten a new leak test since but AFR looks good, other than at times we run a bit rich hitting 11.02-10.88. We only get slightly lean at startup which I believe is normal (15.1) before it calms down to 14.55-14.7 at idle. Vacuum is at -10.1 to -9.88 at idle. During cruising vacuum is at -11 with no foot on the throttle. These numbers all seem relatively normal. We are hitting boost now, 24-25.5psi but with the WDGC maxed at 84%. I am starting to believe this might be a bad spark plug issue since vacuum looks fine and we are running rich at times (fuel not burning correctly I’d assume) and also seeing knock at times after a wide open pull and negative ignition correction on cylinders 1 and 4 ranging from -1.5 to -2.5 depending on the time it happens. My spark plugs are 1 step colder and have about 20k on them. I have new ones sitting in the garage that I’m going to throw on ASAP but want to know your opinions.


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[aruth55]

During the time of having these current plugs car has been flashed countless times stock turbo 93, stock turbo e30 and now for the C39 multiples times as well. The plugs are pregapped plugs from dizzy tuning.


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[TyphoonFiST]

I am running a C39 Hybrid Turbo with a Tial MVS external wastegate set up with a screamer pipe. We have been having trouble hitting boost, and so we got a boost leak test. Sure enough, Dv+ was leaking as well as slightly out the dump. We replaced with a new Dv+ and new wastegate diaphragm. After that we still were not hitting correct boost though, car was more responsive and such but still not peak. We have not gotten a new leak test since but AFR looks good, other than at times we run a bit rich hitting 11.02-10.88. We only get slightly lean at startup which I believe is normal (15.1) before it calms down to 14.55-14.7 at idle. Vacuum is at -10.1 to -9.88 at idle. During cruising vacuum is at -11 with no foot on the throttle. These numbers all seem relatively normal. We are hitting boost now, 24-25.5psi but with the WDGC maxed at 84%. I am starting to believe this might be a bad spark plug issue since vacuum looks fine and we are running rich at times (fuel not burning correctly I’d assume) and also seeing knock at times after a wide open pull and negative ignition correction on cylinders 1 and 4 ranging from -1.5 to -2.5 depending on the time it happens. My spark plugs are 1 step colder and have about 20k on them. I have new ones sitting in the garage that I’m going to throw on ASAP but want to know your opinions.


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Do sparklers every 10k on a modded engine.....Its cheap Maintenance....IMO. If it wasn't a modded Turbo I'd say every 50k at least. If it was a N/a engine I'd say 100k. Let us know your findings!

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[aruth55]

Do sparklers every 10k on a modded engine.....Its cheap Maintenance....IMO. If it wasn't a modded Turbo I'd say every 50k at least. If it was a N/a engine I'd say 100k. Let us know your findings!

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I will let you know! I have a weird itch this could be it just because I’ve rebuilt the waste gate down to every bolt now and from my knowledge my vacuum readings look good. Seeing oscillating peak boost, running rich at weird times and MPG has dropped to 17mpg again. From what I’ve read are symptoms of bad plugs. Thanks for your guidance though typhoon super appreciated, I’m only 20 and got into this stuff like a year ago when I did my intake, dp and exhaust, so I still got a shit ton to learn for sure!


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[aruth55]

Oh and maybe this is worth mentioning, when I had my v band leak at where the wastegate meets the manifold it smelled a bit more gassy than exhausty if that makes sense, so maybe unburned fuel?


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[aruth55]

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[aruth55]

Yknow just checked accessport codes and I’m throwing a P04DB. Everything is plugged in to the intake, but could the connections be messed up due to installing and reinstalling multiple times causing my leak?


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[TyphoonFiST]

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Ignition corrections is a Rabbit hole....do you wanna go down it?

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[aruth55]

Ignition corrections is a Rabbit hole....do you wanna go down it?

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Ah I suppose not. I think that stuff actually all looks pretty good, as well as the misfire count for our engines looks fine to me upon further research. I’m starting to think this is a PCV connection issue due to that code and lack of boost up top.


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[Erick_V]

Model year and mods? I ask incase you are running an aftermarket intake on a 16+ without the evap lines or the P144C "fix". When I had a 2J intake I tripped that code until I messed with the lines, I forgot what I did tbh

 

[aruth55]

Model year and mods? I ask incase you are running an aftermarket intake on a 16+ without the evap lines or the P144C "fix". When I had a 2J intake I tripped that code until I messed with the lines, I forgot what I did tbh

Model year is a 2019. I’m running the mishimoto air intake system. I have the P04DB code only which I thought only the P144C meant the incorrect Evap lines. Not sure when the code started either, but I never had it for the longest time we’re talking close to a year with the intake installed, so I don’t know why it would start now other than a leak of sort. We used fuel lines for vacuum lines which I also saw this code could mean damaged vacuum lines which could also account for my lack of boost without upping the WDGC to full. Have silicon ones arriving this week from stratified. Or a leak in the PCV system I believe also could cause boost issues because it’s connected to vacuum. Not sure, but we didn’t show any vacuum leaks in my smoke test literally a week ago.

Here is my current mod list:

Cobb accessport
Tune+ 93 tune
Cobb rear motor mount
MBRP 3” catback exhaust
Mishimoto air intake system
Whoosh motorsports 3” catless downpipe
Depo racing intercooler
Velossa tech ram air big mouth
Go fast bits dv+
NGK one step colder spark plugs
Whoosh motorsports hot side charge pipe
Whoosh motorsports cold side charge pipe
Whoosh motorsports turbo inlet pipe
Tial MVS 38mm external wastegate
Dual spring setup, large black and small red, 1 bar or 14.50psi total
C39 hybrid turbo setup for external wastegate
Stock exhaust manifold but v-band flange welded on top for external wastegate
ZZPerformance Dump Tube on wastegate
Whoosh motorsports shifter base bushings
Perrin 2” shortie antenna
Billetworkz weighted shift knob
H&R super sport lowering springs
Mishimoto fiesta ST Radiator
RokBlokz black rally mud-flaps
Vegamotorworks v2 wing extension


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[Erick_V]

My mind is going to your PCV connections and that Mishi Intake. Ensure the connections to your valve cover and the intake tube are solid and no chance of leaks. I think adding a check valve to the EVAP lines fixed the code (which is supplied with the P144C fix). I believe it is the same price as plugs ~$40. I don't think it has to do with plugs, when I needed plugs the misfires were VERY audible lol

Edit: however, I would change the plugs. It's about that time and I change mine every year since my misfire issues. Super cheap insurance

 

[aruth55]

My mind is going to your PCV connections and that Mishi Intake. Ensure the connections to your valve cover and the intake tube are solid and no chance of leaks. I think adding a check valve to the EVAP lines fixed the code (which is supplied with the P144C fix). I believe it is the same price as plugs ~$40. I don't think it has to do with plugs, when I needed plugs the misfires were VERY audible lol

Edit: however, I would change the plugs. It's about that time and I change mine every year since my misfire issues. Super cheap insurance

That’s what I’m thinking too, everything seems connected right and tight but couldn’t even the smallest bit be an issue? I’m considering going back to OEM intake just to really get rid of any possible leak issues. I will proceed with the plugs then as well! Do you believe that loose PCV connections at the intake could cause lower peak boost?


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[Erick_V]

That’s what I’m thinking too, everything seems connected right and tight but couldn’t even the smallest bit be an issue? I’m considering going back to OEM intake just to really get rid of any possible leak issues. I will proceed with the plugs then as well! Do you believe that loose PCV connections at the intake could cause lower peak boost?


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Potentially? The intake is always under negative vacuum. I couldn't see it being an issue unless things were REALLY loose, like manipulate the whole part with your hand loose. But I have also seen people have an issue with your intake that have caused the P144C, mainly that VC to intake connection. I wouldn't be too concerned with the boost values, weather plays a big role in that. I'm on a stock snail and I peak ~27.5psi in the summer and I hardly hit 26 in the winter. Go back to the OEM intake and see if that fixes the issue. Check all of your connections and hoses, change plugs and if none of that works then we can go from there.

I personally don't like Mishimoto products as they have a tainted reputation with the FiST platform also with other platforms. I just don't believe in their products, their R&D, QC and their customer service. When I have problems I'm more than happy to pay a little extra to have all that. Mishimoto, to me, is a whole topic in itself lol.

 

[aruth55]

Potentially? The intake is always under negative vacuum. I couldn't see it being an issue unless things were REALLY loose, like manipulate the whole part with your hand loose. But I have also seen people have an issue with your intake that have caused the P144C, mainly that VC to intake connection. I wouldn't be too concerned with the boost values, weather plays a big role in that. I'm on a stock snail and I peak ~27.5psi in the summer and I hardly hit 26 in the winter. Go back to the OEM intake and see if that fixes the issue. Check all of your connections and hoses, change plugs and if none of that works then we can go from there.

I personally don't like Mishimoto products as they have a tainted reputation with the FiST platform also with other platforms. I just don't believe in their products, their R&D, QC and their customer service. When I have problems I'm more than happy to pay a little extra to have all that. Mishimoto, to me, is a whole topic in itself lol.

I’m only really concerned with the boost values because Adam is saying I’m hitting lower boost levels than I should be at my wastegate duty cycle. For example, at 73% I should be seeing 25/26psi of boost, but now at 84% I am really seeing only 24.5psi consistently, maybe 25-25.5psi on the first pull of the day. My wastegate has 14.5psi springs, so full 84% max on the boost controller should technically be netting 30psi of boost or close to it. I’m sure I’m not telling you anything you don’t already know, just wanted to explain my situation a little more. Then I got that leak test a week ago which revealed the dump pipe slightly leaking to which I replaced the wastegate diaphragm, and then the DV+ VTA leaking which I replaced with a brand new DV+ (not a VTA) and we are still seeing the same issues. I then saw that code today and thought that could possibly be my issue. I unfortunately didn’t keep my stock intake like an idiot so I might have to buy a new one. I’m just thinking if air is escaping after the MAF sensor from one of those connections, the car may think it’s getting more air than it really is, causing less boost. I suppose that’s my logic?


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[aruth55]

Well it’s for sure a PCV issue of some sort because today the CEL came on.


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[TyphoonFiST]

Well it’s for sure a PCV issue of some sort because today the CEL came on.


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Codes*?

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[aruth55]

Codes*?

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P04DB is the code, I read a few places it could also mean vacuum lines are bad.


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[aruth55]

We have replaced the vacuum lines with the silicon lines from stratified. We are doing the spark plugs today, and have new intercooler piping couplings and clamps arriving from whoosh Wednesday. If problem is not remedied we will proceed with another leak test... we also flashed back down to our tune with 73% WDGC where we make 23.5psi when we should be making 25psi, rather than continuing to force the car to make full boost by keeping the wastegate closed longer. Seems to have fixed whatever was wigging out causing the PCV code by doing that. I’d say forcing full boost with a leak isn’t a good idea.


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[Erick_V]

Do you have a check valve on the evap line?