cyl misfire help

[f4m0u5]

Sorry forclong post but i want to lay it all out there.


Car is on 034 stage 2+ superduper tb 91 oct file. apr coils with 10k miles and ngk oem plugs woth 5k miles gapped to .026. car had carbon cleaning, waterpump/ thermo stat and new intercooler brics as precation 6 months ago. 0 coolant loss


3 weeks ago i replaced my hpfp with a new oem unit and at same time added 034 piston upgrade. car looked great in logs . rarely hiting 70% duty 0 codes. sent logs to 034 and they said looks perfect.


2 weeks later installed 034 super duper tb and switched to the correct tune. log here https://datazap.me/u/f4m0u582090/goo...?log=0&data=45

a week later went to do a draggy run and at the top of 3rd start of 4th i got a epc/ cel. pulled over instantly shut off car and checked for codes. CYL 1, CYL 3, CYL 4 misfire WTF. owned car for 3 years never 1 misfire.

cleared code and did a log of issue happening.

https://datazap.me/u/f4m0u582090/bad...?log=0&data=45


Evrything seems ok i belive in the log above besides lean after the misfire unless im missing something.

WHAT I HAVE TRIED:
tried gapping plugs down to .024 and the samething happens with misfire but now just cyl 4 . swapped the coil from cyl 4 to 1 and still cyl 4 misfire......


current log with plug gap at .024 (happens right around 7k rpm in log)
https://datazap.me/u/f4m0u582090/7k-...?log=0&data=45


what gets me is then next drive it may drive fine. such as this log this morning with 0 hicups.

https://datazap.me/u/f4m0u582090/goo...?log=0&data=45

Then ride home back to misfire cyl 4.

[Fresh.S4]

spark plugs coilpacks injectors

[f4m0u5]

spark plugs coilpacks injectors

i understand its alot to read. but plugs are new, i even gapped lower now at .024.

i also tried to swap coil packs from cyl 4 to a different cyl and stil got same cyl 4 misfire. (coils new/10k miles apr version)


as far as injectors they dont leak ( fuel pressure rises after engine shuts off and doesnt drop pressure) But i gues this doesn't mean they are fireing correctly

[Fresh.S4]

swap injectors around :) thats the best way. you'll be fine reusing the orings etc. your looking for the misfire to follow the injector.

also watch your misfire counter at idle. mine was going off like crazy but car would drive normal around town/freeway. only at wot would i misfire too. turned out to be 2 of them going out, so i bought 6 new ones. dont fk with refurb or cleaning. get new.

[RoofRails]

i understand its alot to read. but plugs are new, i even gapped lower now at .024.

i also tried to swap coil packs from cyl 4 to a different cyl and stil got same cyl 4 misfire. (coils new/10k miles apr version)


as far as injectors they dont leak ( fuel pressure rises after engine shuts off and doesnt drop pressure) But i gues this doesn't mean they are fireing correctly

Do you by chance still have your cats. Your fueling is way off from bank to bank. I have never seen trims differ that much from bank to bank. Your injector duty cycle on injector #1 Bank 1 is 1 ms higher then injector #3 bank 2. Your boost is also pegging the request and I don't remember you mentioning a ported blower.

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[RoofRails]

Those trims are not normal. IMG_20221116_200148.jpgIMG_20221116_200226.jpg

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[f4m0u5]

Those trims are not normal. IMG_20221116_200148.jpgIMG_20221116_200226.jpg

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not sure whats goin on there. wasnt doing it before tb tune


as far as cats i have relocated cats a few feet back from engine, with rear o2 wires extended and siting behind the aftermaket cats. id think id get a code for the rear o2 if they clogged up . im running spacers (the cats i have arent strong enough to get rid of cel.from removing factory cats) i gues i wouldnt get a code if they broke up only if they clogged. but if they broke up i shouldt get misfire only if clogged

[RoofRails]

pretty sure those trims are because the misfire just happend, not sure tho i will look i to it more


as far as cats i have relocated cats a few feet back from engine, with rear o2 wires extended and siting behind the aftermaket cats. id think id get a code for the rear o2 if they clogged up . im running spacers (the cats i have arent strong enough to get rid of cel.from removing factory cats) i gues i wouldnt get a code if they broke up only if they clogged. but if they broke up i shouldt get misfire only if clogged

You can go through the logs if you want and double check but those weird trims were in the 2 I opened and it wasn't just a single instance.

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[f4m0u5]

you are correct. it wasnt doing that before not sure why all of a sudden, if you check my first log with the tb up top it wasnt doing this, then all of a sudden started to (funky short term and inj duty)

[RoofRails]

you are correct. it wasnt doing that before not sure why all of a sudden, if you check my first log with the tb up top it wasnt doing this, then all of a sudden started to (funky short term and inj duty)

Right , the secondary O2s you have in the remote cats are responsible for LTFT. Those look normal. The primary O2s are responsible for STFT which are out of wack. Maybe one of them is on the way out , maybe a injector is hosed up or maybe one of those cats has collapsed. I wouldn't count on getting a efficiency code for a failed cat that is clogged up especially when the secondary O2 is in a spacer.

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[f4m0u5]

Right , the secondary O2s you have in the remote cats are responsible for LTFT. Those look normal. The primary O2s are responsible for STFT which are out of wack. Maybe one of them is on the way out , maybe a injector is hosed up or maybe one of those cats has collapsed. I wouldn't count on getting a efficiency code for a failed cat that is clogged up especially when the secondary O2 is in a spacer.

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i thought ltft are jsut the long term adjustments and the stft are on demand adjustments. rear o2s should only have to do with monitoring cat health?


i orderd 2 new bosch o2 sensors ( mine have 120k miles on them) they will be here tomoro. im also going to try a dif plug on cyl 4.


i also think i will remove the tb just for the fuck of it to make sure its nothing going on there at some point. But only 1 thing at a time then test.

[f4m0u5]

swap injectors around :) thats the best way. you'll be fine reusing the orings etc. your looking for the misfire to follow the injector.

also watch your misfire counter at idle. mine was going off like crazy but car would drive normal around town/freeway. only at wot would i misfire too. turned out to be 2 of them going out, so i bought 6 new ones. dont fk with refurb or cleaning. get new.

after 10 min idle , 25 min of easily driving, had 1 misfire cyl 2, 1 for cyl 4, and 3 for cyl 5. Ill try some bg 44k. i try to use it once evry 6 months and its been 9 months since used last.



034 also suggested doing another throttlebody alignment. but im pretty certain the tb would not cause 1 side to be that rich ( -up to 20% fuel in stft) while other sides closer to 0 or on the positive side.

[RoofRails]

i thought ltft are jsut the long term adjustments and the stft are on demand adjustments. rear o2s should only have to do with monitoring cat health?


i orderd 2 new bosch o2 sensors ( mine have 120k miles on them) they will be here tomoro. im also going to try a dif plug on cyl 4. And some bg 44k. i try to use it once evry 6 months and its been 9 months since used last.


i also think i will remove the tb just for the fuck of it to make sure its nothing going on there at some point. But only 1 thing at a time then test.

The wide band is responsible for the bulk of the real time adjustments and the secondary O2s do the fine tuning. The strategy being to make long term adjustments to minimize the adjustments the Primary O2s make. That's what I found in my research. Thats the factory strategy anyway and based off of a few issues people have seen with failing secondary O2s and running catless without a Test pipe file I believe most of the OTS tuners retain that strategy.

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[sepheroth86]

The wide band is responsible for the bulk of the real time adjustments and the secondary O2s do the fine tuning. The strategy being to make long term adjustments to minimize the adjustments the Primary O2s make. That's what I found in my research. Thats the factory strategy anyway and based off of a few issues people have seen with failing secondary O2s and running catless without a Test pipe file I believe most of the OTS tuners retain that strategy.

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So what you are telling me is that my car will run lean over time since I have gutted cats and no test pipe file?

[RoofRails]

So what you are telling me is that my car will run lean over time since I have gutted cats and no test pipe file?

There was lots of talk about that before test pipe files became a thing. Whether it's lean or rich would probably depend on if you use spacers or not. Either way I don't think anyone ever proved that running spacers on test pipes on a catted file caused any long term damage. Maybe your MPG could be a little more dialed in but I'm thinking that's about the extent of it. Once you go WOT the LTFT get locked down and the Primary O2s take care of things. I don't think you have anything to worry about. If your concerned you could always run a few logs and see how things look.

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[f4m0u5]

cats are rattleing when i hit them. have appt to remove them today since they are under car its easy

[RoofRails]

cats are rattleing when i hit them. have appt to remove them today since they are under car its easy

Let us know what you find out and if it turns out to be the cats either post your set up or a link to it so others can be on alert if they have a similar set up.

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[f4m0u5]

Let us know what you find out and if it turns out to be the cats either post your set up or a link to it so others can be on alert if they have a similar set up.

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of course thanks. Nothing worse then finding some one with same issue and then them not finishing up the tread with what fixed their issue!


currently running heat shielded gutted redstar cats up top, and thrn magnaflow 2.25 epa complient high flow cats (59955) after the flex pipes.

I would replace the cats but not putting same parts in for $400 that mah have already failed.... and to buy gesi they are guna cost $1100 for epa complient cats.


I really liked the sound exhaust was producing although lately seemed louder on start up and little more raspy on wot. maybe they have been slowly failing past month or so

[RoofRails]

of course thanks. Nothing worse then finding some one with same issue and then them not finishing up the tread with what fixed their issue!


currently running heat shielded gutted redstar cats up top, and thrn magnaflow 2.25 epa complient high flow cats (59955) after the flex pipes.

I would replace the cats but not putting same parts in for $400 that mah have already failed.... and to buy gesi they are guna cost $1100 for epa complient cats.


I really liked the sound exhaust was producing although lately seemed louder on start up and little more raspy on wot. maybe they have been slowly failing past month or so

I Have Redstar Gutted cats to a pair of small canister type resonators to a set of GESI Non EPA cats. I got a EPC a few weeks ago and thought I smoked one but when I checked on them they looked like new. So far I'm happy with how they are holding up. They won't clean up the smell as much as the EPA cats do but they are much easier on the wallet.
Model # 10025
https://www.amazon.com/GESI-G-Sport-.../dp/B08842K8Z220220612_185635.jpg20220412_145225.jpg

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[f4m0u5]

i was thinkin of giving them a tey even tho bot epa complient. but was also nervous since my buddy blew his motor from gesi cats clogging(the expensive ones)

[Fresh.S4]

if you have gutted cats, then its not a cat problem? no one mentioned a p0420
if it was the sensor, you'd throw a code too i think.

if your gonna replace yours, get another set of generic 2.5" 200 cell magnaflow cats. I am running them no problems.

[f4m0u5]

problem ended up being 1 cat broke into a chunk that kept clogging the outlet






ENGINE SAVED!

[RoofRails]

problem ended up being 1 cat broke into a chunk that kept clogging the outlet






ENGINE SAVED!

Congratulations on catching it prior to hurting anything ! Just one more win for 034s logging tool.

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[f4m0u5]

Congratulations on catching it prior to hurting anything ! Just one more win for 034s logging tool.

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thanks for help!

As of now dnt have to worry about cats melting now. i will probably throw those gesi non epa cats when i can. already not digging the new rasp up top rpm or the smell lol