missfiring and runs strange @ 5k rpm - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

ogatxx2 · 04-20-2014, 05:52 PM

hi guys, so firstly i want to pardon my bad english, im from Sweden so i will try to type so u will understand me =)

so my S14 sr20det is acting strange, i have searched the interwebz for answers several hours and i cant find a topic with the same problem as me, if u rev the car no gear or with clutch in, when u come to 5k it starts to missfire, sounds like a Bee*R almost, and this is with the throttle pushed like 2/4 or something so u rev it really slow, it also happens when u cruise in say 1st gear and rev slowly to 5k, no boost, if i have full throttle it doesnt missfire but according to my wideband gauge it goes from 11.5 to 14:0 @ 5k after 5k it drops back to high 12 low 13s, so lean i would say, or what i have been reading..

i have tested to change:
spark plugs
coilpack harness
ignitor chip
brand new Jecs 550CC injectors
coilpacks with a good known one
checked grounds and it seems good..
checked TPS
looked for vac leaks changed all vac lines
MAF is fine i guess because car dies or will go reaaaly bad with it disconnected
changed airfilter because i couldnt think of something else to change..
changed fuelfilter with a z32 one
only thing i havent checked is timing, i will do that asap when i get a strobe light, but the car runs good if u shift before 5k rpm always starts and when warm idles at 900rpm or similar..

specs on car:
AEM F/ic 6
jecs 550cc
3" exhaust
FMIC
aftermarket intake manifold and exhaust manifold
garret gt2860RS
turbosmart boostcontroller
pod filter
wahlbro 255L fuelpump
z32 fuelfilter
hks ssqv bov
54MM race radiator with two 10" fans
and with all mods on the car the car has a tune for it on dyno with 339hp and 401NM so the car is tuned.. i dont know what else to do.. please push me in a direction =) <3
sorry for long and messy post but im just trying to say everything i have done and tried

*fliprayzin240sx* · 04-20-2014, 06:43 PM

Double check your base timing. Also, what spark plugs are you running and what is your gap? I'd try closing the gap more if its missing in the higher RPM. OEM gap is .030, gap them down as low as .025.

ogatxx2 · 04-20-2014, 06:46 PM

ok thanks for fast answer, im using BCPR7ES gapped to 0.8mm, will check base timing as soon as i get a strobe light so i can check it, i also have a spare CAS i can put in but it feels like if the cas is broken the car wouldent start at all..

yeah forgot to say i have 3bar in fuelpressure at idle, it feels like i have checked and tested alot things and nothing helps =( but if the timing is OK what can i do then?

04-20-2014, 05:52 PM	#1
ogatxx2 Join Date: Apr 2014 Location: Sweden Age: 32 Posts: 2 Trader Rating: (0) Feedback Score: 0 reviews	missfiring and runs strange @ 5k rpm hi guys, so firstly i want to pardon my bad english, im from Sweden so i will try to type so u will understand me =) so my S14 sr20det is acting strange, i have searched the interwebz for answers several hours and i cant find a topic with the same problem as me, if u rev the car no gear or with clutch in, when u come to 5k it starts to missfire, sounds like a Bee*R almost, and this is with the throttle pushed like 2/4 or something so u rev it really slow, it also happens when u cruise in say 1st gear and rev slowly to 5k, no boost, if i have full throttle it doesnt missfire but according to my wideband gauge it goes from 11.5 to 14:0 @ 5k after 5k it drops back to high 12 low 13s, so lean i would say, or what i have been reading.. i have tested to change: spark plugs coilpack harness ignitor chip brand new Jecs 550CC injectors coilpacks with a good known one checked grounds and it seems good.. checked TPS looked for vac leaks changed all vac lines MAF is fine i guess because car dies or will go reaaaly bad with it disconnected changed airfilter because i couldnt think of something else to change.. changed fuelfilter with a z32 one only thing i havent checked is timing, i will do that asap when i get a strobe light, but the car runs good if u shift before 5k rpm always starts and when warm idles at 900rpm or similar.. specs on car: AEM F/ic 6 jecs 550cc 3" exhaust FMIC aftermarket intake manifold and exhaust manifold garret gt2860RS turbosmart boostcontroller pod filter wahlbro 255L fuelpump z32 fuelfilter hks ssqv bov 54MM race radiator with two 10" fans and with all mods on the car the car has a tune for it on dyno with 339hp and 401NM so the car is tuned.. i dont know what else to do.. please push me in a direction =) <3 sorry for long and messy post but im just trying to say everything i have done and tried

04-20-2014, 06:43 PM	#2
fliprayzin240sx Man w/ CTSV & a Car Seat Join Date: Aug 2002 Location: Tampa Posts: 17,998 Trader Rating: (19) Rides Gallery: fliprayzin240sx Feedback Score: 19 reviews	Double check your base timing. Also, what spark plugs are you running and what is your gap? I'd try closing the gap more if its missing in the higher RPM. OEM gap is .030, gap them down as low as .025. __________________ If you think Zilvia has too many assholes... CLICK HERE!!!

04-20-2014, 06:46 PM	#3
ogatxx2 Join Date: Apr 2014 Location: Sweden Age: 32 Posts: 2 Trader Rating: (0) Feedback Score: 0 reviews	ok thanks for fast answer, im using BCPR7ES gapped to 0.8mm, will check base timing as soon as i get a strobe light so i can check it, i also have a spare CAS i can put in but it feels like if the cas is broken the car wouldent start at all.. yeah forgot to say i have 3bar in fuelpressure at idle, it feels like i have checked and tested alot things and nothing helps =( but if the timing is OK what can i do then?