SR20 S13 Goes Rich, Lean, Rich - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

nothinbuddadreamer · 11-08-2018, 02:27 PM

Okay so I have a fairly stock sr, it’s rebuilt with around 5k or so on it,mls head gasket and arp head studs, I bought this engine off my buddy, barely put any miles on it since I got it in the car, I drove it when the engine was still in his car and it ran great, no hiccups, but now that it’s in my car it’s doing some weird stuff, it feels like it pulls timing at around 3000rpms and leans out. At WOT my afr’s are around 11:1 but at around 3000rpms it leans out to 13:5 -14:1 and stops pulling, like it just hits a spot and then as soon as it reaches around 4700rpms or so it richness back up to 11:1 and pulls hard as fuck all the way to redline, I have no vacuum leaks or boost leaks, all my grounds look good. I have a vent to atmosphere bov but that never effected it when it was in my friends car. My fuel pump is hard wired to a constant 12v with a relay, it’s an ISR 255, Injectors are deischworks oem replacements, so the stock 370’s or whatever the factory ones are rated at. Also the engine does idle pretty lean at around 17:1. If anyone could help me diagnose this that’d be great, it’s been a weird process, I’m thinking of adding a few more engine to chassis ground and seeing if that helps at all.

11-08-2018, 02:27 PM	#1
nothinbuddadreamer Join Date: Aug 2017 Location: PA Posts: 10 Trader Rating: (0) Feedback Score: 0 reviews	SR20 S13 Goes Rich, Lean, Rich Okay so I have a fairly stock sr, it’s rebuilt with around 5k or so on it,mls head gasket and arp head studs, I bought this engine off my buddy, barely put any miles on it since I got it in the car, I drove it when the engine was still in his car and it ran great, no hiccups, but now that it’s in my car it’s doing some weird stuff, it feels like it pulls timing at around 3000rpms and leans out. At WOT my afr’s are around 11:1 but at around 3000rpms it leans out to 13:5 -14:1 and stops pulling, like it just hits a spot and then as soon as it reaches around 4700rpms or so it richness back up to 11:1 and pulls hard as fuck all the way to redline, I have no vacuum leaks or boost leaks, all my grounds look good. I have a vent to atmosphere bov but that never effected it when it was in my friends car. My fuel pump is hard wired to a constant 12v with a relay, it’s an ISR 255, Injectors are deischworks oem replacements, so the stock 370’s or whatever the factory ones are rated at. Also the engine does idle pretty lean at around 17:1. If anyone could help me diagnose this that’d be great, it’s been a weird process, I’m thinking of adding a few more engine to chassis ground and seeing if that helps at all.