Yo, this misfiring problem is driving me nuts, help a brotha out!

[AdrenalineS14]

So my car misfires real bad on cold start, it idles fine but the motor shakes a little and all i hear is "pop pop pop..." from the exhaust even when im in the car i can feel it, as it warms up and reaches operating temp it gets better but still misfires, also driving the car seems fine but when i let off and come to a stop i can still hear and feel misfiring not super noticeable but if you really concentrate you'll notice it, fuel filter is fairly new so is the plugs and gapped to .28, checked the coil packs(not running) just pulled them out and checked the contact spring and ohms checks out fine, fuel pressure is good as well, i do have deatschwerks 810cc injectors and heard that there not terrible but not good that there alright injectors so im guessing maybe those could every well be the problem how can i check these, just need some helpful input from you "misfire fixer upper gurus" lol it be nice to hear from someone that went through the same shit im going through with troubleshooting everything and finding out that it was the injectors THANK YOU ZILVIANS!:bow:

[KiLLeR2001]

This thread is worthless without your entire setup listed and the tune.

[AdrenalineS14]

This thread is worthless without your entire setup listed and the tune.

wow haha ohhh damn my bad...

1995 s14 with s13 sr20det

z32 maf on a blitz cone filter
freddy intake mani
810cc injectors on walbro 255 and stock fuel rail
stock valves, stock cam gears
BC 264 cams and BC springs and retainers
power enterprise PE1420 turbo on a silkroad knockoff mani
tomei elbow, invidia 3" exhaust system
tomei head gasket
mahle piston and rings 86.5mm
all acl race bearings and acl thrust bearing
eagle rods
greddy oil pan
oil remote kit
xs power fmic kit
hsk bov
greddy profec b boost controller
power fc

tuned by my local tuner running at 15psi 310whp it was misfiring then but not as bad, also tuner also noticed it was misfiring very faintly @ around or just past 6500rpm other than that the graph showed no spikes or dips it was a smooth nice climb on the power band.

[KiLLeR2001]

I would get a set of known working coilpacks and swap them out with yours. Coilpacks tend to act strange at certain temperatures. Also, how do your spark plugs look? Taking a picture of each one and posting on here might help determine what is going on. If one looks strange compared to the other 3, that could be your problem cylinder.

Tip: If you're going to be hitting rev's near redline I would highly suggest rocker arm stoppers.

[AdrenalineS14]

oh yeah i forgot to list that i have tomei RAS lol.... but yeah ill post some pics of the plugs later on today... its after 12am over here and im beat lol.

[AndyG]

i have the same problem but i have very low hp and it will barely go up and hills and cant rev over 4500. Its only running on the 2nd and 3rd cylinders... im hoping mine is just the injectors.

[r33nota240]

i would try unpluging the injector with the car running check all of them this way and see which cyl changes the miss the least and from my experience it is most likely a dirty injector. did u flush the fuel system good when u installed the new injectors?

[r33nota240]

and andy i would look at ur plugs and see if there black or soked and if so it would be a coil problem or maybe a wiring issue. all ur coils will have 12v once the key is on so u can always check that also.

[AndyG]

and andy i would look at ur plugs and see if there black or soked and if so it would be a coil problem or maybe a wiring issue. all ur coils will have 12v once the key is on so u can always check that also.

I got mine working.. i just replaced the injector of the dead cylinder and then got new spark plugs. runs great now.

[AdrenalineS14]

yo, been sick... ill post plug pics tomorrow.... but also decided to upgrade fuel rail and injectors im looking at the JGY rail and MSD injectors 96lb/1000cc Nissan, 240sx, nissan sentra, nissan sentra se-r, G20, nissan skyline gtr, nissan silvia, S13 (http://www.jgy.cc/240sx/fuel.htm) ... they also have the clips i need to install with, is that really all i need for install, swap injector clips new fuel hoses? I already have nismo fpr... the new stuff will just replace the stock fuel rail and deatschwerks 810cc injectors i also have a power fc and im still within my tuners year subscription so i can install and have him fine tune the new setup... haha also how are the MSD's good/bad??? thanks in advance

[AdrenalineS14]

... ohhhh also where do i solder the resistors since the MSD's are low impedance thanks in advance!

[AdrenalineS14]

sorry for the delay guys, alright forget the rail and injector crap... back to my original problem, so i pulled my plugs out to snap some pics and i find that i have no batteries for the camara :bash:!!! anyways they look good except for #2 looks alittle funny, compared to the others which are of a greyish brown color while #2 looks like an off white color on the "hook" of the spark plugs, what does that mean? also rechecked ohm on the injectors (#1-11.6) (#2-11.5) (#3-11.6) (#4-11.8) i believe to be good and then checked my coilpacks which all came out to 1.4ohms i read elsewhere that they should be around 1.0-1.1ohms so im kinda worried about mine being bad but idk what do you guys think?

[KiLLeR2001]

Use this to help...

NGK Spark Plugs USA (http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp)

[r33nota240]

the brighter the white the less the fuel. how much boost u running? u might try closing ur plug gap up a little if over stock boost.

[r33nota240]

have u tryed a diffrent maf sensor?

[AdrenalineS14]

Use this to help...

NGK Spark Plugs USA (http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp)
well by that all mine look pretty much like the first one which is normal... will get pics up as soon as i get some batteries lol

the brighter the white the less the fuel. how much boost u running? u might try closing ur plug gap up a little if over stock boost.

have u tryed a diffrent maf sensor?

Haven't tried a different MAF, im running 16psi, plugs were first gaped down to .028 then down to .025 and still misfiring


how can i check that im getting 12v power to coil packs and injector plugs does the car just need to be on the "on" position right before i crank or does she need to be running?

[AdrenalineS14]

...about the 12 volts i just fiddled with the injector plugs got myself a paper clip straighten it out and stuffed it in the + end and grabbed the multimeter and touched + to + and - to chassis i aint no electrical guru so just wondering if i did it right it showed me 12.27v.

[AdrenalineS14]

pics...

DSC06101.jpg picture by AdrenalineSeoul - Photobucket (http://s1125.photobucket.com/albums/l586/AdrenalineSeoul/?action=view&current=DSC06101.jpg#!oZZ2QQcurrentZZhttp%3A%2F%2F s1125.photobucket.com%2Falbums%2Fl586%2FAdrenaline Seoul%2F%3Faction%3Dview%26current%3DDSC06101.jpg)
2 & 1

DSC06101.jpg picture by AdrenalineSeoul - Photobucket (http://s1125.photobucket.com/albums/l586/AdrenalineSeoul/?action=view&current=DSC06101.jpg#!oZZ3QQcurrentZZhttp%3A%2F%2F s1125.photobucket.com%2Falbums%2Fl586%2FAdrenaline Seoul%2F%3Faction%3Dview%26current%3DDSC06102.jpg)

4 & 3

DSC06101.jpg picture by AdrenalineSeoul - Photobucket (http://s1125.photobucket.com/albums/l586/AdrenalineSeoul/?action=view&current=DSC06101.jpg#!oZZ1QQcurrentZZhttp%3A%2F%2F s1125.photobucket.com%2Falbums%2Fl586%2FAdrenaline Seoul%2F%3Faction%3Dview%26current%3DDSC06103.jpg)

2 again... let me know what you guys think

[AdrenalineS14]

anybody?

also had another Q lately ive been getting REALLY bad gas mileage i filled up drove about a 100miles and im already at half a tank, wonder if its possibly cause I have both o2 sensors hooked up i have the factory one plugged in at the turbo elbow and plx wideband hooked up on the downpipe along with the power fc o2 sensor turned on thanks in advance!