terrible missfire issue

s300 and SManager software questions & answers
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racepak
Posts: 36
Joined: Sun Apr 03, 2011 3:39 pm

terrible missfire issue

Post by racepak »

hey guys, i really need your help on this one,

here are some details:
smanager 2.4.5.0
s300v3 31269
1995 civic
p28
d16z6 eagle and vitaras , 59300 cam ,delphi 1000cc low-z injectors with a honda resistor box,

so.... iv been tuning cars successfully for about 10+ years mainly with crome, now i'm using hondata, so i can safely say that i know what i am doing when i comes to tuning,

i have a very bad misfires on a costumer car, i never had this issue before on a honda. and its driving me crazy,

second, i am 100% sure that the problem is not in the cars that i tried to tune, (not a mechanical or a electrical problem) the car works perfect with stock ecu and stock injectors'. also i would like to mention that i tried several injector types on this car. so the problem is not the injectors. and also not the resistor box,

here is what happened in order :
- while beginning a tune of a new car. i noticed a very bad idle misfire. tried to control it, adjusted the dizzy, set fuel pressure, the usual stuff, and when i noticed i cant tune the misfires (not with Afr and not with offsets) i tried my equipment on a different car, and had the same resaults, bad missing.
-in the mean while i didn't know how to solve the issue, so i replaced all the capacitors in the ecu's,swapped ecu's, changed spark plugs and wires, cap and rotor, changed injectors dsm440cc pte550cc pte780cc pte1000cc and even with id 1000's, changed ignition coils. complete dizzys, map sensors, checked for electrical failures, and couldn't find any issues,
-got a brand new laptop since i assumed mine was old/bad
- went back to the misfiring cars and still no change.

here are the symptoms:
-at idle the car misfire a constant misfire, its a very repeatable and not a your occasional lean pop.
-whatever afr i give it 12.5-15.5 i still get the same miss, although the pop is less noticeable at richer afr of course. but still not acceptable because some of these cars i tuned in the past and they didn't had these issues,
-with all accessories off (headlights off) the misfire feels really bad, 14.4-14.0v
-when turning on headlights/defroster the misfire feels a little better 14.0-13.8v , but its still there no matter what afr i set,
-the batt voltage is pretty much the same +-0.6v so i know i'm not falling on my face with the preset injector offsets, so is i see the problam is not with injector offsets,
-when lowering idle ignition timing from the map from 16 to about 4 the miss feels like its completely gone,

as for now i am lost on this,


uploading map and log now......

here are some videos of the miss .you wont hear the misfire with laptop speakers, you need some bass yo
https://www.youtube.com/watch?v=AGvNAbLJI-k
thanks alot
Last edited by racepak on Tue Sep 08, 2015 8:41 am, edited 1 time in total.
racepak
Posts: 36
Joined: Sun Apr 03, 2011 3:39 pm

Re: terrible missfire issue

Post by racepak »

here is my map and 2 logs
in log 3 i turned the lights on and off several times so you could see the difference.
thanks
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Spunkster
Site Admin
Posts: 22737
Joined: Fri Sep 20, 2002 5:06 pm
Location: Hondata

Re: terrible missfire issue

Post by Spunkster »

The datalogs do not show the AF ratio.
racepak
Posts: 36
Joined: Sun Apr 03, 2011 3:39 pm

Re: terrible missfire issue

Post by racepak »

yes, thats why i uploaded a video, i will try to send a datalog with a afr tommorow,
racepak
Posts: 36
Joined: Sun Apr 03, 2011 3:39 pm

Re: terrible missfire issue

Post by racepak »

No one has an idea?
User avatar
Spunkster
Site Admin
Posts: 22737
Joined: Fri Sep 20, 2002 5:06 pm
Location: Hondata

Re: terrible missfire issue

Post by Spunkster »

Based on the video and the datalogs I really don't see or hear a terrible misfire. You have also posted on Honda-tech and said this happens with other tunable systems as well. It does not sound like an issue with the Hondata or any of the other systems.
racepak
Posts: 36
Joined: Sun Apr 03, 2011 3:39 pm

Re: terrible missfire issue

Post by racepak »

well. i hear it and that what matters, the car works clean as a whistle with any other platform now,+ with stock ecu and injectors, we had a spark plug issue that was solved, i sent the costumer to buy a s300 because i wanted a solid platform, it has nothing to do with each other,
I dont know how can you not hear the misfire in the video, its clearly there,

i want to send my s300 to be tested, is this not possible?
User avatar
Spunkster
Site Admin
Posts: 22737
Joined: Fri Sep 20, 2002 5:06 pm
Location: Hondata

Re: terrible missfire issue

Post by Spunkster »

facts:
Large injectors will always have poorer idle quality than smaller injectors .
We recommend smaller saturated injectors instead of peak and hold as they have faster opening times at low duty cycle where it is most important
A staff vehicle here makes about 315hp with only 440cc RC injectors (these are high impedence...saturated) and do not do not require a resistor box.
There are many large injectors available now that are saturated and do not require a resistor box.

observation:
without a cat you may get some un-burnt fuel popping, especially with injectors that atomize poorly.

suggestion:
test with Hondata and stock injectors

What are hp goals on this?
racepak
Posts: 36
Joined: Sun Apr 03, 2011 3:39 pm

Re: terrible missfire issue

Post by racepak »

I know all these stuff you just wrote, :)

i will test with stock injectors again :D and make a proper log with afr.
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