Misfire Sr20det - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Habibi240 · 10-06-2015, 04:50 PM

Searching and reading for a while !
Figured I'd make a thread

So my s13 sr has a random misfire at idle

Has a really bad cut out putting anything after 20% throttle

I don't know if my worn cam lobes have anything to do with it
<a href='http://i.imgur.com/HRp65Rh' title=''><img src='http://i.imgur.com/HRp65Rh.jpg' alt='' title='Hosted by imgur.com' /></a>

Timing marks are correct but when using a timing gun it was way off to get it at 15* the cas is at the end of the adjustment window ...

Things I've tested

Tried a freinds igniter
Unplugged each coil pack and injector
Tested cts and cleaned connection
Cleaned maf
Checked all clamps for possible boost leak (haven't done a test)

Mods
Walbro 400 (I know it's excessive)
Stock fuel lines
Z32 fuel filter (1hour of run time on it)
Stock 370inj
Wiseco 9.0 comp Pistons 87mm
Apexi 1.5 - 87
Stock valve tran fresh seals
T28 s15 bb
Fmic

It was doing the idle bog/misfire before I had a piston meltdown but only popped every now n then under load .

I'm gonna do a boost leak soon but in the mean time can I get some ideas tossed up..

Let me know if you need any more info.

Thanks

Also I don't know afr #s yet . Wideband on the way

cbeuglas · 10-06-2015, 05:11 PM

Here are a few ideas. Clogged fuel injectors. Test fuel pressure. TPS has to be unplugged when checking timing, also I could not get an accurate reading off the timing loop. I had to use a plug wire (ka24) between the number one coil and number one spark plug to get an accurate timing reading.

Sent from my SAMSUNG-SM-G920A using Tapatalk

cbeuglas · 10-06-2015, 05:13 PM

Also what is the vac. at idle as it could be very well be a boost leak.

Sent from my SAMSUNG-SM-G920A using Tapatalk

Habibi240 · 10-06-2015, 05:26 PM

I have a cheap ass boost gauge that only reads boost and I did the spark plug wire loop trick

Habibi240 · 10-06-2015, 05:35 PM

Oh and plugs gapped at 32

*blksylv* · 10-06-2015, 06:02 PM

Have you tried another CAS?

Habibi240 · 10-06-2015, 06:29 PM

No actually I haven't I could test mine right ? Imma search that now

*blksylv* · 10-06-2015, 07:25 PM

I'm not too sure. I had an issue with an misfire at idle, replaced a bunch of things and it ended up being the cas. My misfire would get worse the longer I drove it. It would bog a little under boost though.

Sills · 10-12-2015, 03:10 PM

My Rb had a nasty misfiring issue, especially in the higher rpm range.
I tossed in some fresh Ngk V-power BRK7E(s?) plugs and gapped them to 0.22.
Running perfectly now, way better than the old NGK iridiums that were in it.
Only costed me about 25$ for 6 plugs. Not sure what ones to use in an Sr as mine blew up long before I got to change the plugs in it.

Habibi240 · 10-12-2015, 03:53 PM

It was my ignitor chip I forgot to update you guys

10-06-2015, 04:50 PM	#1
Habibi240 Zilvia Member Join Date: Aug 2015 Location: Chicago Age: 29 Posts: 228 Trader Rating: (0) Feedback Score: 0 reviews	Misfire Sr20det Searching and reading for a while ! Figured I'd make a thread So my s13 sr has a random misfire at idle Has a really bad cut out putting anything after 20% throttle I don't know if my worn cam lobes have anything to do with it <a href='http://i.imgur.com/HRp65Rh' title=''><img src='http://i.imgur.com/HRp65Rh.jpg' alt='' title='Hosted by imgur.com' /></a> Timing marks are correct but when using a timing gun it was way off to get it at 15* the cas is at the end of the adjustment window ... Things I've tested Tried a freinds igniter Unplugged each coil pack and injector Tested cts and cleaned connection Cleaned maf Checked all clamps for possible boost leak (haven't done a test) Mods Walbro 400 (I know it's excessive) Stock fuel lines Z32 fuel filter (1hour of run time on it) Stock 370inj Wiseco 9.0 comp Pistons 87mm Apexi 1.5 - 87 Stock valve tran fresh seals T28 s15 bb Fmic It was doing the idle bog/misfire before I had a piston meltdown but only popped every now n then under load . I'm gonna do a boost leak soon but in the mean time can I get some ideas tossed up.. Let me know if you need any more info. Thanks Also I don't know afr #s yet . Wideband on the way

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10-06-2015, 05:11 PM	#2
cbeuglas Zilvia Member Join Date: Apr 2013 Location: United States Posts: 265 Trader Rating: (2) Feedback Score: 2 reviews	Here are a few ideas. Clogged fuel injectors. Test fuel pressure. TPS has to be unplugged when checking timing, also I could not get an accurate reading off the timing loop. I had to use a plug wire (ka24) between the number one coil and number one spark plug to get an accurate timing reading. Sent from my SAMSUNG-SM-G920A using Tapatalk

10-06-2015, 05:13 PM	#3
cbeuglas Zilvia Member Join Date: Apr 2013 Location: United States Posts: 265 Trader Rating: (2) Feedback Score: 2 reviews	Also what is the vac. at idle as it could be very well be a boost leak. Sent from my SAMSUNG-SM-G920A using Tapatalk

10-06-2015, 05:26 PM	#4
Habibi240 Zilvia Member Join Date: Aug 2015 Location: Chicago Age: 29 Posts: 228 Trader Rating: (0) Feedback Score: 0 reviews	I have a cheap ass boost gauge that only reads boost and I did the spark plug wire loop trick

10-06-2015, 05:35 PM	#5
Habibi240 Zilvia Member Join Date: Aug 2015 Location: Chicago Age: 29 Posts: 228 Trader Rating: (0) Feedback Score: 0 reviews	Oh and plugs gapped at 32

10-06-2015, 06:29 PM	#7
Habibi240 Zilvia Member Join Date: Aug 2015 Location: Chicago Age: 29 Posts: 228 Trader Rating: (0) Feedback Score: 0 reviews	No actually I haven't I could test mine right ? Imma search that now

10-12-2015, 03:10 PM	#9
Sills Leaky Injector Join Date: Nov 2014 Location: Canada Posts: 121 Trader Rating: (0) Feedback Score: 0 reviews	My Rb had a nasty misfiring issue, especially in the higher rpm range. I tossed in some fresh Ngk V-power BRK7E(s?) plugs and gapped them to 0.22. Running perfectly now, way better than the old NGK iridiums that were in it. Only costed me about 25$ for 6 plugs. Not sure what ones to use in an Sr as mine blew up long before I got to change the plugs in it.

10-12-2015, 03:53 PM	#10
Habibi240 Zilvia Member Join Date: Aug 2015 Location: Chicago Age: 29 Posts: 228 Trader Rating: (0) Feedback Score: 0 reviews	It was my ignitor chip I forgot to update you guys