sr20det misfire - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

rappadan · 01-25-2007, 09:09 PM

just finished sr (redtop) swap into s14, car started and was misfiring, found #2 coilpack was bad, started back up, still misfiring, found #1 misfiring also, switched coilpacks, plug, injector did not help, did compression check had to same readings all the way across. if you unplug the coil connector slightly (not all the way) it will smooth out for about 2 seconds then run rough again, had another coil harness, switched it does the same thing, also only does that when cold, when engine heated up this would not work. any ideas why #1 is misfiring?????

koshile · 01-26-2007, 01:21 AM

Try reseting the ECU. That solved my problems with misfiring after changing all ignition components on a sr

methodofpayment · 01-26-2007, 01:46 AM

also try to check spark plugs

Enjuku Racing · 01-26-2007, 09:11 PM

I would check the continuity/voltage per S14 SR FSM on all the coil packs and injectors - also remove the coil pack subharness and check continuity from each individual coil pack to where it plugs into the main engine harness.

Sounds like the wiring might be compromised somewhere in the subharness - possibly from shipping, age, etc.

jims14sr20 · 01-30-2007, 10:19 AM

I just had that same problem. It turned out to be an injector.

Z U L8R · 01-30-2007, 10:31 AM

what's the motor idling at? did you confirm the base timing at 15*btc? what are the plugs/gap? is there 93 octane in the tank?

***dorkidori_s13*** · 01-30-2007, 10:37 AM

grounding on stock SR coilpacks suck...you may want to considder ordering a grounding coilpack cover from Phase2motortrend (easiest way to do it...its plug n play)...on one of the shop cars we were having misfire problems with a redtop...we created a grounding plate kit for the motor and it smoothed right out...u may want to considder this before u start swapping out injectors or tearing apart wiring harnesses...its a quick and cheap fix...even if its not the problem...it does help greatly when u start producing higher numbers in horsepower

rappadan · 01-31-2007, 07:50 PM

alright so did some more tests, i had spark a week ago, checked again, now number 1 has no spark, had another ignitor and put it on and tested spark again, now i did have spark on number 1. started it up, ran on all 4 cylinders, thought i had it fixed, but after 1 minute it started missing again. i still had the spark tester on it and noticed i still had spark but it was weak. it was still pushing me in the direction of a bad ignitor. i have 2 and tested both of them per the FSM and they both tested bad. so i ordered another used one that is guaranteed to be good, before i put it on i tested it, it did test bad per FSM. i put it on, same result ran fine for a minute then started misfiring again. has anyone else tested ignitors before, i find it hard to believe i have 3 bad ignitors, it seems unlikely. i want to test the wiring in between ecu and ignitor and igniter to coil pack but the ecu pinout in the s14 FSM is incorrect, anybody know where to find one for a redtop ecu?? and anybody got any suggestions on my problem????

Crono562 · 01-31-2007, 08:35 PM

its starting to really sound like a wiring problem in the harness or sub-harness, i wish i had the FSM for s13 so i could tell ya the pinout, but im sure someone else on here can tell ya

rappadan · 02-03-2007, 01:51 PM

im in the process of tracing all the wiring right now, i havent found a problem yet, but is seems like i have a short because it runs fine for a minute then the ignitor gets really hot and starts misfiring, any other suggestions??anybody ever seen this before??

01-26-2007, 09:11 PM	#4
Enjuku Racing Zilvia.net Advertiser Join Date: Feb 2002 Location: Clermont, FL Age: 41 Posts: 3,049 Trader Rating: (29) Feedback Score: 29 reviews	I would check the continuity/voltage per S14 SR FSM on all the coil packs and injectors - also remove the coil pack subharness and check continuity from each individual coil pack to where it plugs into the main engine harness. Sounds like the wiring might be compromised somewhere in the subharness - possibly from shipping, age, etc. __________________ Office: 352-241-8399 / 1-888-SR20DET (772-0338) YouTube.com/c/EnjukuRacingParts http://www.enjukuracing.com [email protected]

01-30-2007, 10:37 AM	#7
*dorkidori_s13* ITS LISA'S FAULT!!! Join Date: Jun 2003 Location: Las Vegas Age: 43 Posts: 7,496 Trader Rating: (41) Feedback Score: 41 reviews	grounding on stock SR coilpacks suck...you may want to considder ordering a grounding coilpack cover from Phase2motortrend (easiest way to do it...its plug n play)...on one of the shop cars we were having misfire problems with a redtop...we created a grounding plate kit for the motor and it smoothed right out...u may want to considder this before u start swapping out injectors or tearing apart wiring harnesses...its a quick and cheap fix...even if its not the problem...it does help greatly when u start producing higher numbers in horsepower __________________ Check out my IG for what I'm up to! DORKIDORI INSTAGRAM!!!

01-31-2007, 08:35 PM	#9
Crono562 Leaky Injector Join Date: Jan 2005 Location: 562 Posts: 140 Trader Rating: (3) Feedback Score: 3 reviews	its starting to really sound like a wiring problem in the harness or sub-harness, i wish i had the FSM for s13 so i could tell ya the pinout, but im sure someone else on here can tell ya __________________ Mikey "Whitey" Ernst 'www.justdrift.com'

01-25-2007, 09:09 PM	#1
rappadan Leaky Injector Join Date: Jan 2007 Location: Herndon,VA!!! Age: 39 Posts: 54 Trader Rating: (0) Feedback Score: 0 reviews	sr20det misfire just finished sr (redtop) swap into s14, car started and was misfiring, found #2 coilpack was bad, started back up, still misfiring, found #1 misfiring also, switched coilpacks, plug, injector did not help, did compression check had to same readings all the way across. if you unplug the coil connector slightly (not all the way) it will smooth out for about 2 seconds then run rough again, had another coil harness, switched it does the same thing, also only does that when cold, when engine heated up this would not work. any ideas why #1 is misfiring?????

01-26-2007, 01:21 AM	#2
koshile Join Date: Mar 2006 Location: Houston Posts: 27 Trader Rating: (0) Feedback Score: 0 reviews	Try reseting the ECU. That solved my problems with misfiring after changing all ignition components on a sr __________________

01-26-2007, 01:46 AM	#3
methodofpayment Leaky Injector Join Date: Jun 2006 Location: So. Cal 818 Posts: 108 Trader Rating: (0) Feedback Score: 0 reviews	also try to check spark plugs

01-30-2007, 10:19 AM	#5
jims14sr20 Join Date: Jul 2003 Location: Cincinnati, OH Age: 44 Posts: 22 Trader Rating: (0) Feedback Score: 0 reviews	I just had that same problem. It turned out to be an injector.

01-30-2007, 10:31 AM	#6
Z U L8R Zilvia FREAK! Join Date: Jan 2007 Location: Georgia Age: 43 Posts: 1,194 Trader Rating: (0) Feedback Score: 0 reviews	what's the motor idling at? did you confirm the base timing at 15*btc? what are the plugs/gap? is there 93 octane in the tank?

01-31-2007, 07:50 PM	#8
rappadan Leaky Injector Join Date: Jan 2007 Location: Herndon,VA!!! Age: 39 Posts: 54 Trader Rating: (0) Feedback Score: 0 reviews	alright so did some more tests, i had spark a week ago, checked again, now number 1 has no spark, had another ignitor and put it on and tested spark again, now i did have spark on number 1. started it up, ran on all 4 cylinders, thought i had it fixed, but after 1 minute it started missing again. i still had the spark tester on it and noticed i still had spark but it was weak. it was still pushing me in the direction of a bad ignitor. i have 2 and tested both of them per the FSM and they both tested bad. so i ordered another used one that is guaranteed to be good, before i put it on i tested it, it did test bad per FSM. i put it on, same result ran fine for a minute then started misfiring again. has anyone else tested ignitors before, i find it hard to believe i have 3 bad ignitors, it seems unlikely. i want to test the wiring in between ecu and ignitor and igniter to coil pack but the ecu pinout in the s14 FSM is incorrect, anybody know where to find one for a redtop ecu?? and anybody got any suggestions on my problem????

02-03-2007, 01:51 PM	#10
rappadan Leaky Injector Join Date: Jan 2007 Location: Herndon,VA!!! Age: 39 Posts: 54 Trader Rating: (0) Feedback Score: 0 reviews	im in the process of tracing all the wiring right now, i havent found a problem yet, but is seems like i have a short because it runs fine for a minute then the ignitor gets really hot and starts misfiring, any other suggestions??anybody ever seen this before??