sr20det s13 blacktop Help

[Mental_One]

Hello chaps ,
I'm having trouble sorting out a misfire i have , hoping someone might have some suggestions for me!
so story goes like this :

My car developed a very slight misfire when building boost upon inspection i found i had a cracked coilpack (factory ones ).
Rather than buy a new one from nissan i decided to buy a set of Splitfire coilpacks.
Once fitted car would idle/rev fine drive under light load fine , but once under boost load about 4000rpm (18psi) it would break down not rev any further! seems to do this in any gear under any conditions.
I had installed new spark plugs also so i tried back to my old ones with no success. I have tried testing connections and the like but with no change.

I have since swapped back to my factory setup with the cracked coilpack patched up but the problem is still there ! its less aggressive than with my splitfires in the sense i can rev through the miss but its still there.

My mods are:
gt2871R Turbo (running about 18psi)
Haltech E8 ecu (map sensor)
550cc injectors
bosch 044 fuel pump

few other things but they shouldnt contribute to the problem.

Only other thing i can think of was i changed my water pump at the same time but i cannot see what i would have disturbed to cause the issue.

Hope someone can give me some ideas :).

Thanks
Ben

[4x4le]

hows the weather down under currently? I dont know if your winter is the same time as ours, however if your car is tuned in the safe side it could be that you are border line with not enough timing for when it gets cold. The same thing (only opposite) could be for if it is hot there only with too much timing. Have you had any recent weather changes??

Right at 4k should be close to where you start making good tq with the listed turbo, it is also a lower rpm and timing is crucial there, 4-5k rpms is where sr's blow up with bad tunes.

Let me know how much timing your running from 3500 to 5k
Take a screen shot of your timing map and also let me know if your logs look true to what your map is showing what you should be running.

[mptjimmy]

i have a s14 with a bad fuel pump do the exact same thing, under high boost it would hesitate BAAD, then after changing the turbo, plugs, wastegate, and ecu.. same... new fuel pump... and runs like a charm... it was previously a walboro 255.. had to put in a new one.

[Mental_One]

hows the weather down under currently? I dont know if your winter is the same time as ours, however if your car is tuned in the safe side it could be that you are border line with not enough timing for when it gets cold. The same thing (only opposite) could be for if it is hot there only with too much timing. Have you had any recent weather changes??

Right at 4k should be close to where you start making good tq with the listed turbo, it is also a lower rpm and timing is crucial there, 4-5k rpms is where sr's blow up with bad tunes.

Let me know how much timing your running from 3500 to 5k
Take a screen shot of your timing map and also let me know if your logs look true to what your map is showing what you should be running.

Weather is a bit up and down at the moment as we are in spring currently !

I hadn't taken that sort of change into account as this current tune has been in the car for two years now with no issue, is it possible for tunes to change? or perhaps require change over time?

I don't currently have a copy of map , i let my tuner take care of all that for me. I doubt he would have it on record from my tune so long ago :(. I would need to go back too him to get a copy of the map of my ecu as i don't have the required cable/software.

Your post makes alot of sense and may well be the cause !

[Mental_One]

i have a s14 with a bad fuel pump do the exact same thing, under high boost it would hesitate BAAD, then after changing the turbo, plugs, wastegate, and ecu.. same... new fuel pump... and runs like a charm... it was previously a walboro 255.. had to put in a new one.

Im hoping this is not the case as the pump is not that old , but in saying that it could be the case as i do not know what the problem is too rule out the possibilty. How would be the best way to test a fuel pump is operating properly?

[05civse]

any updates? I have a similar problem

[05civse]

replaced coils, all is right in the world again :)

[alex350z_240sx06]

i had the same problem ur sr is running lean need more fuel, check ur fuel pressure need to be 40-60 psi i change my pump and it run good.
good luck