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

blksylv · 03-18-2010, 01:27 PM

well, a couple days ago i noticed my car had a slight miss at idle and it kinda did a lil bit of bucking upon decel and had a slight stutter when the turbo would spool. my vacuum is at 18 in hg upon warming up and it was at 20 before it started acting funny. ive swapped in good coilpacks from one of my friends, checked plugs, cleaned maf,ran fuel injector cleaner, changed the coilpack harness with one that was in better condition and redid all of my grounds and changed the temp sensor. only things i havent checked were the ignitor and ecu. also upon fully waming up itll idle at 900rpm then itll start to stumble and drop 2 around 750-800rpm where it usually idles but itll just stumble a bit. my batt voltage is 13.4-.6 and around 12.5 with all accessories turned on. i wouldnt think it would be a vacuum leak but ill prolly check 2morrow when i get home. mods are s13 redtop, z32 maf, safc2,s14 t28, nismo fpr, ngk bkr7e gapped at .28, fmic, 3" exhaust, but it has a slight pin hole in the dp. if you have any ideas feel free 2 chime in. thanx.

Prez · 03-18-2010, 02:35 PM

it run fine with SAFCII before? sometimes they act weird... hole in exhuast wont affect anything as long as it is after O2... check for leaks since you have low vacuum otherwise you'll have to check compression on the cylinders... 18 sounds low... not horrible but low... and it doesnt sound like it's a huge problem just a slight studder...

blksylv · 03-18-2010, 02:45 PM

ya it ran fine w the safc2 b4, been running it 4 quite a while now, hole is in the flex pipe on the dp, it was just fine a couple days ago as far as vacuum and ive read anywhere from 17-21 is fine as far as vac, i was thinking mayb it could b bad gas but idk im just kinda stumped, checked over vac lines and everything seemed 2 b fine so idk

BlitzRPS13 · 03-18-2010, 03:23 PM

What fuel pump are you using?

Prez · 03-18-2010, 05:15 PM

17-22 is Universal but yes you are barely within specs...

ditto on pump...

wait your using the plugs from a SE-R correct regapped? how much boost you pushing? cause it might be jumping too soon at idle... but if your running the boost you might need it...

blksylv · 03-18-2010, 06:32 PM

im running a circuit sports 255 and running about 7-10lbs of boost, its been running fine as is since last june with no prob. this just startda couple days ago. gt it compression checked n june and it was 150 across the boards. it still pulls as strong as it always has, it also backfires alot on decel, well alot more than usual. im startin 2 lean more 2wards vac leak but idk . i can hear it misfire faintly during the initial warm up but once it completes warm up itll missfire thn idle will drop 2 750-800 and vac will go from 20 2 18 in hg and it start 2 stumble a bit.

blksylv · 03-19-2010, 07:14 AM

update: put some seafoam in the gas tank yesterday and filled up. burnt about a 1/4 tank of gas yesterday riding around and when i got home it idled fine. this morn started it, it stumbled a bit nt as much as its been doing tho. upon fully warming up stumbled once idle dropped from a lil under 900 to around 780 and idled fine no misfires but it idled at -16 in hg so now im like wtf. it didnt stutter on accel like its been doing and no jerking on decel anymore so idk wats up. any ideas?

Prez · 03-19-2010, 02:29 PM

its idling at 16hg?, did you touch the idle adjustment? what octane you been putting in?

blksylv · 03-19-2010, 03:42 PM

ya and 93 and i did a month ago when i set the timing

blksylv · 03-21-2010, 04:10 PM

anyone? had a leak around the flange of the bov fixed it but still has a slight miss and low vacuum even rechecked the plugs and theyre still good so im stumped

blksylv · 03-24-2010, 08:44 AM

well fixed the stumble, it was a fried ground, but now car runs pig rich and still idles at 18 in hg...

03-18-2010, 02:35 PM	#2
Prez Zilvia Junkie Join Date: Dec 2008 Location: Newark, Delaware Posts: 466 Trader Rating: (7) Feedback Score: 7 reviews	it run fine with SAFCII before? sometimes they act weird... hole in exhuast wont affect anything as long as it is after O2... check for leaks since you have low vacuum otherwise you'll have to check compression on the cylinders... 18 sounds low... not horrible but low... and it doesnt sound like it's a huge problem just a slight studder... __________________ "soft so you can't even enjoy it"

03-18-2010, 05:15 PM	#5
Prez Zilvia Junkie Join Date: Dec 2008 Location: Newark, Delaware Posts: 466 Trader Rating: (7) Feedback Score: 7 reviews	17-22 is Universal but yes you are barely within specs... ditto on pump... wait your using the plugs from a SE-R correct regapped? how much boost you pushing? cause it might be jumping too soon at idle... but if your running the boost you might need it... __________________ "soft so you can't even enjoy it"

03-19-2010, 02:29 PM	#8
Prez Zilvia Junkie Join Date: Dec 2008 Location: Newark, Delaware Posts: 466 Trader Rating: (7) Feedback Score: 7 reviews	its idling at 16hg?, did you touch the idle adjustment? what octane you been putting in? __________________ "soft so you can't even enjoy it"

03-18-2010, 03:23 PM	#4
BlitzRPS13 Zilvia Member Join Date: Jul 2007 Location: Edmonton, AB, Canada Posts: 244 Trader Rating: (3) Feedback Score: 3 reviews	What fuel pump are you using?