Misfiring Rotrex K20a HELP!

Hey guys,

Just wondering if i can get some help/opinions on what could be the cause of my issue.

Its a Jdm K20a with a Rotrex C38-61 SC on it. Its recently been tuned and was running great for about a week.

Now its developed a bad misfire under WOT.

The Car drives good cruising around at low rpm with under 5% throttle, but as soon as i step on it.. The RPM climbs to about 3k and then starts misfiring/hesitating/sputtering. It is as if boost is just blowing the spark completely out.

So far i have tried:

- New TPS Sensor
- Different coilpacks
- Iridium Spark plugs heat range 7-9s with gapping from 0.032" to 0.020"
- Checked fuel pressure (datalogs show that it isnt leaning out or anything and AFRs stay fine)
- New MAP Sensor
- Air intake not clogged etc (Boost is being registered in datalogs, so there is no leaks)
- No leaks on my IM
- Quick visual check over most my sensor plugs that the pins were all still intact.

I think thats about it..

It started after i took the car for a 1hr drive; so heat may have been a factor. I also filled up my car with fuel. Could possibly be a bad batch? even though it drives fine on minimal throttle and cruising?

If you have an idea's id love to hear them!

Any help will be appreciated :)


Thanks

Ash.

have you checked fuel pressure under load? or just at idle?

Only just at idle because my gauge is in my bay. But if it was losing fuel pressure under load would it be leaning out? Or is that not the case?

During the datalog's where you can see it misfiring at about 4-4.5k at WOT, AFRs are still staying constant and not jumping all over the place.. This got me thinking it isnt a fuel issue? But i could be wrong..

probably try upload datalog?

Do you know how to upload datalog files onto here?

Quote:

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Originally Posted by Tom eg5

Do you know how to upload datalog files onto here?

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just zip it, upload to any uploading site and link it here

It wouldn't let me upload on this forum but the link is in my build thread here:

http://www.k20a.org/forum/showthread...37705&posted=1

Quote:

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Originally Posted by Tom eg5

It wouldn't let me upload on this forum but the link is in my build thread here:

http://www.k20a.org/forum/showthread...37705&posted=1

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bad fuel could be a possibility i guess, what was it?
bp 98?

try use copper plugs and gap it to what you want?
dont think youre suppose to re-gap iridiums

btw why is it reading constant vss at 80kph lol

Its tuned on Caltex e85.

You can gap the iridiums if your careful. Thats what i had to do when the car ran fine... Then after the longer drive it started playing up again. Ive been reading that coilpacks can break up under load if they are shorting out.. But i have spare ones ive tried and nothing changed.. Would be bad luck if my spare set had a busted one too haha.

have you tried to reupload calibration to ecu?

Yeah i tried that a couple of times. Same issue :(

if you have a spare set of copper plugs, i'd probably piss the iridiums off.

also could be a bad case of fuel.

are you doing the data logging while driving as well or just idle?

i guess next to try would be more e85 from different station.
i dont see anything funny in the datalog other than that constant vss, revs really slow from 3krpm to 4krpm like 3 seconds?
you got any other longer WOT datalog? this one is like only 2 seconds of WOT.

Yeah that data logging was a short drive. Only has one run in it though where i hit 100% throttle. And you can see the rpm break up as its misfiring.

Bad fuel would be a good outcome! I just thought if it was that, it would run bad all the time under any throttle conditions, and idle bad.

Quote:

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Originally Posted by mocchi

i guess next to try would be more e85 from different station.
i dont see anything funny in the datalog other than that constant vss, revs really slow from 3krpm to 4krpm like 3 seconds?
you got any other longer WOT datalog? this one is like only 2 seconds of WOT.

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My VSS doesnt work so i have to set a constant speed signal. Yeah thats it misfiring and hesitating. Um a have a couple but the WOT look pretty much the same as that.. I don't let the rev's slowly climb any higher because it just feels so bad.

Quote:

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Originally Posted by hoddy
I have recently had the rare opportunity, of being able to tune my car using AFM & then MAP based tuning
My car has a Rotrex supercharger 12 psi boost, J tune exhaust, air intake ect, after having the car dyno tuned it was making 330 BHP which I thought was great
After driving around for a week I noticed that the car was jerky, idled roughly & had a power band like a 2 stroke, running very rich
I ended up contacting E-Tunze & Vitialy (Vit) e-mailed me so I sent the tune to him, & basicaly needed to re tune the tune
Once the AFM tune was complete (I thought) the car was wonderfull, mid range increased, no flat spots, throttle response good & then Vit asked me if I had considered a MAP based tune as the AFM tune was maxed out & there was still more left to tune
So I thought why not as if it was no good I could always change back
After a lot of data logging & re mapping & after about 2/3rds of the way through the spark plugs started to misfire & so they were replaced (BKR8EIX)
In the end this tune won me over as throttle response was better, part throttle excellent, there is extra mid range & a little more in the top end, transition to V-tech & boost more linear, but it is the overall feel of the car was much better, smoother
To be fair because of the new plugs I put the AFM tune back & drove the car to work & back about 60 klms & noticed straight away the difference, the car was blunted more sluggish, less responsive, part throttle not as good ( do not get me wrong still very good)
I then re installed the MAP tune & it just re confirmed how much better it is, I would recommend this type of tune even though there is a few dramas with the fuel guage (just nick picking)
When I get the chance I will compare both tunes on a dyno run & post the results, should be interesting
I would like to thank Vit for his help & patience, it certainly taught me a few lessons

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http://www.8thcivic.com/forums/honda...ap-vs-afm.html

http://type-r-owners.co.uk/forums/sh...-tractor/page5

so revolves around spark plugs, coil packs and injectors. hondata says around 12:1 for sc, yours showing 11:1 on those 2 seconds WOT?
maybe too rich?

Quote:

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Originally Posted by fatboyz39

Update: 15/05/10 Tuning Update!

KRAFTWERKS FTW! Simply an amazing supercharger kit. I've spent some time today tuning the car both on low and high cam. Unfortunately, we couldnt completely tune high cams due to spark issue (need cooler spark plugs). All in all, the car has been fully tuned on low cam. It makes amazing power off VTEC, and simply screams in vtec up to 8000rpm. Without vtec, the car makes a healthy 150kw @5800rpm's

We could only managed one run up to 7800rpm before it started to misfire again. It made 210kw @7800rpms 10psi on 0 cam angles. With more fine tuning of cams angles, ignition & fuel, we are hoping to make close to the 230-240kw mark @ 8300-8400rpms.

We'll be back on the dyno on tuesday with the new gearbox to finish off the high cam tuning

Here are some pictures of the car on the dyno

http://i4.photobucket.com/albums/y13...e/IMGP0784.jpg

http://i4.photobucket.com/albums/y13...e/IMGP0783.jpg

http://i4.photobucket.com/albums/y13...e/IMGP0786.jpg

http://i4.photobucket.com/albums/y13...e/IMGP0790.jpg

Dyno Run Video
http://i4.photobucket.com/albums/y13...h_IMGP0788.jpg (http://s4.photobucket.com/albums/y13...t=IMGP0788.flv)

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So far ive tried Iridium 8s, HKS Race plugs (8s), Iridium 9s and Copper 7s. Same problems even with a range of gapping

Its a conservative/safe tune so id rather it run a bit rich. But yeah i had the same problems on the dyno with it breaking up at high rpm's.. And the new plugs managed to work for a bit to get some tuning done. The next day i then gapped the plugs down and the car ran awesome.

should call your tuner and ask for some help
post at hondata forums as well maybe?

He's baffled as well as everything looks ok on my MAP and Datalogs.. Yeah ive posted it over on k20a.org too. Been researching for a few weeks and im just running out of idea's now.. Ill play around with different coilpack combinations tomorrow and see if i do infact have 2 that are broken.

If its not fuel or spark, it will be compression. So ill be doing a compression test soon if i still have no luck. Hopefully haven't blown my headgasket.

tell me how your mate test the coilpack and ill test mine tomorrow, this should help rule out your spare coilpack dud

What is your power/ground source to the ignition system like?
Does this get worse with heat?

How do i check power/ground source to my ignition? Just test the coilpack plugs?

Well it must, as it was fine driving around for 10-15min drives.. Still was up at running temp.. But as soon as i took it on the 1hr drive it messed up. Weird..

Have you checked your Coolant Temp Sensor? What do your plugs look like when they get pulled out (ie Heavily Carbon'd, any danage to the electrode)? 11:1 does sound a bit rich but the more i read your symptoms, the more i believe it is a coil pack breaking down. Have you tried with brand new ones and not just what is lying around?

My coolant temp sensor seems to reading correctly as its almost the same as my defi gauge. Yeah, when i pull the plugs out after a run they are a little powdered whiteish, but not too bad. No not just yet, but ill try and borrow my mates known working ones and see if it fixes the issue.

Checked known coilpacks and a different KPRO.. No deal.

Also, my cam angle is going to 50* at 3500 (Basically when it misfires and hesistates and rev's barely climb) and then easing off to 30* at the higher rpm's?

It seems to be happening as soon as i hit the low vtec boundary

White plugs mean that it is running lean... But you say that you running 11:1 AFR :o

One of the results running E85 is that it strips / cleans your fuel system, this is usually good but can be a problem on your first initial use because of how it strips your fuel tank and can block injectors downstream (you will probably still show fuel pressure but get little flow to your cylinders). Take out your injectors and get them cleaned. Could also be a good idea to replace all your filters (especially if you have changed to non OEM units) and run a fuel / injector cleaner through a tank of fuel too. I don't think a fuel based miss-fire would be enough to show a majorly leaner wide-band reading either.

Honest bet this will fix your problem, however few other things to try

* leakdown test maybe you valves are passing compression through the seat ?
* try stick to copper plugs heat 7ish - always had miss-fire problems in the past with boosted setups and iridiums.
* Im not too familiar with the Kpro - but can you bring up in your datalog the firing signal for each individual coil pack ? possibly determine if this miss-fire is only happening in one specific cylinder or if its random over them all?

Good luck :)

I forgot you running e85 oops.

^ good thinking buddy. You should be able to do a 'power balance' test on aftermarket ECU's to determine if a miss is evident and using you can datalog it for various driving conditions.

Quote:

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Originally Posted by Sexc86

One of the results running E85 is that it strips / cleans your fuel system, this is usually good but can be a problem on your first initial use because of how it strips your fuel tank and can block injectors downstream (you will probably still show fuel pressure but get little flow to your cylinders). Take out your injectors and get them cleaned. Could also be a good idea to replace all your filters (especially if you have changed to non OEM units) and run a fuel / injector cleaner through a tank of fuel too. I don't think a fuel based miss-fire would be enough to show a majorly leaner wide-band reading either.

Honest bet this will fix your problem, however few other things to try

* leakdown test maybe you valves are passing compression through the seat ?
* try stick to copper plugs heat 7ish - always had miss-fire problems in the past with boosted setups and iridiums.
* Im not too familiar with the Kpro - but can you bring up in your datalog the firing signal for each individual coil pack ? possibly determine if this miss-fire is only happening in one specific cylinder or if its random over them all?

Good luck :)

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Good post :thumbsup:

what fuel filter are you running ash?

Aeroflow inline. I tried bypassing it and it didnt change anything either..

Thanks for the comments and thoughts. Ill keep it all in mind.

Its not a small misfire, basically across all cylinders.. Sputtering/cutting out and barely revving any higher than 4-5k.

Could be a mechanical problem.. haven't quite got that far yet as it drives fine when not in vtec/cruising. No sensors seem to be playing up in kpro and ive checked most my sensor plugs back to the ecu and they seem fine.

Starting to exhaust my mechanical knowledge and thinking it may be something a bit more complicated... Hopefully a local tuner up here is going to have a look at it and find the problem for me!

I had a car come in with a rough idle and found that #1 piston had not enough oil to it and chewed out some of the bore.

You checked air leaks, you checked fuel pressure and leaks, you checked spark and leads.

You need to take a big step now as all small steps are exhausted ... * starts chanting * take apart the block.

P.S. Did you get fuel pressure in the rail and injectors?

^ I doesn't seem all small steps are taken yet. Before the op starts majorly ripping apart his setup he should get his injectors ultrasoniclly cleaned + flush his fuel system with a fuel system cleaner. Not sure if any fuel system cleaner would react with e85 - if in doubt run some 98.

Also just because he is getting fuel pressure at the rail does not mean his cylinders are getting the required fuel units if the injectors are blocked :)

To the Op - does your car have this problem if you disable vtec in your kpro ?

Quote:

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Originally Posted by raidbaws

I had a car come in with a rough idle and found that #1 piston had not enough oil to it and chewed out some of the bore.

You checked air leaks, you checked fuel pressure and leaks, you checked spark and leads.

You need to take a big step now as all small steps are exhausted ... * starts chanting * take apart the block.

P.S. Did you get fuel pressure in the rail and injectors?

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Yep no air leaks whatsoever, builds boost good. Fuel pressure is good. Spark plugs have been changed 4 times using different heat ranges and gapping. have tested coilpacks with known good ones.

haha do not want to take apart the motor. Not going to be happy if my motor is damaged after 2 drives on the street...

To be honest if my car is cutting out/misfiring barely allowing the car to rev over 5k, wouldnt i see a huge lean spike on my datalogs? They stay at 11.2 to 11.5 the whole pull. Fuel starvation would cause a splutter but not what im experiencing i don't think.. But i can only check. Thanks for the input. Ive checked all my fuel components for blockages just incase, and my ID1000s are about 100k's old so they are brand new.

I should post up an incar gopro vid when i next take it for a test. To me it feels like an electrical/sensor problem but i could be completely wrong.

I shall keep researching and trying things in the mean time. Thanks for the help guys :D

I know i sounds like a broken record but i worked on a setup recently with nearly identical symptoms to yours, we changed everything ! and the problem was fixed with a bottle of fuel system cleaner from supercheap. Not saying this will definitely fix yours but sometimes its the simple things that are overlooked.

I dont think you should rely on your wide-band 100% for fault finding your fuel system as the sensor is downstream from your engine. The miss-fire may only be minuscule and in one cylinder - it may not be enough for your wideband to accurately capture as some can have a slow-ish response rate.

Maybe just remove your injectors, tap them out and see if there is any debris, get a good bottle of fuel system clean from supercheap and run it in for a bit. At least these steps wont chew your wallet and only cost you a little bit of time.

Good luck dude :)

GoPro it so we can actually hear what is happening.

Haha you are taking us all over the place champion.. first feeling like fuel splutter NEK MINNIT self-diagnosed sensor splutter :confused:

How do you know fuel pressure is GOOD.. what are you reading? At high rpm maybe your fuel pump cannot handle the sudden 'go' that you are after. This may be it IF whilst slowly accelerating, your fuel pump CAN handle this but CANNOT handle quick response WOT.

Goodluck :thumbsup:

haha sorry. Just trying everything at the moment im losing my mind.

Because i dont run a vacuum line to the fpr yet it sits at 70psi all the time. 4k isnt high rpm :P.. Ive also tried a 255 and 400 walbro's. Both doing the same thing..

There were no issues on the dyno holding 70psi using both fuel pumps all the way up to 8200.

But yeah, defintely something weird going on.

Ill get a gopro vid happening when i take it for a drive, ill try tomorow arvo.

is the problem resolved yet ASH!!!?!?!

Have you checked the exhaust cat? Could be blocked.. :p

^ its all too late.
OP has decided to part it out and sell it all.

Mod. to please close thread.

Quote:

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Originally Posted by Snoop_gee

^ its all too late.
OP has decided to part it out and sell it all.

Mod. to please close thread.

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I think he found the problem,

He hasn't said anything yet, so he will update the issue before the thread gets closed. So in future when people get a similar issue this thread might save them time or their lifes.

Quote:

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Originally Posted by Snoop_gee

^ its all too late.
OP has decided to part it out and sell it all.

Mod. to please close thread.

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Is this your thread???????????

So after everything i had just had enough of the car. I knew the problem would be something so simple and stupid in the end. I guess it just made me realise i need to stop spending money on this thing, and move onto something else! I had many more plans for the car this year, but i had to think realistically that by the end i finished them the car would owe me close to 80k.. And would forever be a civic. I was only 50% going to part out, until i receieved a great offer on my motor setup that i could not turn down..

Anyway, pulled the whole car apart. Engine bay stripped and interior out.. Begin taking off the exhaust and we find this..

http://i814.photobucket.com/albums/z...ps7a4c7238.jpg

http://i814.photobucket.com/albums/z...psb1dbea4b.jpg

The centre of my cat had just blown completely out and clogged my exhaust. The thing is though, i changed my axle back to my muffler whilst i was testing things. It must had been crushed and lodged further up my exhaust somehow, then reaching this point and not going anywhere. There was basically 5x 2mm holes in this squashed cone of metal.. :\

Im 80% this was my problem because it all makes sense now.. Anyways.. Live and learn guys, always check your cat's! haha.

http://i814.photobucket.com/albums/z...ps57dd4b80.jpg

Holy fuk lol

You can imagine the amount of backpressure this thing was causing when it started to build boost!

Quote:

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Originally Posted by Snoop_gee

^ its all too late.
OP has decided to part it out and sell it all.

Mod. to please close thread.

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Quote:

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Originally Posted by Vvvtec

Is this your thread???????????

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lmaoo

Wow, something so simple!

wow, was that a ceramic or metal cat?

what brand ash, so we know to stay well clear

Fairly sure it was a magnaflow 50cell race metal cat. I could be wrong but the guy who built my exhaust told me this...

Were you measuring your egt's at all ? If so what values were you seeing ?

Nah i wasnt measuring those.

The thing is, while it was the cat being deformed and blocked in the end that was hard to diagnose, at the start it could of been any number of problems. But while all the other parts listed were changed the damage to the cat had already been done. I think that the cat was a symptom of the problem, Not the cause but this is just my $0:02c

Reading through the first post, Im thinking the TPS isn't setup correctly in the ECU. Then Im thinking the Map sensor isnt plumbed up right. Who could have guessed it's the cat... bad luck mate, sorry to hear you are parting it out!

Actually, the problem is just the limits of the OEM map sensor

This sensor goes 5v @ 10~12psi & the S/C in question will exceed this...
My guess is the car was likely tuned at WOT & not at part throttle high rpm.
Chances are the tuner didn't notice the MAP sensor going 5v & the car made it to the road
Dyno sheet says WOT the car makes good power & all is well... etc etc
But the owner uses part throttle & revs it a bit to avoid the annoying BOV sound that these set-ups have...
MAP sensor sees 5v but at part throttle... yet the fuel map delivers the fuel required of WOT...
Say bye bye cat...