Alright, so i just scooped a silvia off this site recently, I bought it knowing the engine wasnt in the best of running condition. I was told that the headgasket was needing replacement. Now, im just posting on here to get a second opinion as i know nothing about turbo cars let alone nissan engines yet so i dont replace the headgasket for nothing. (previous honda nut :oops: ) It runs, and not too roughly at idle. It will rev up a bit (blue/black spews fom the exhaust). but after i let off and the bov kicks, it backfires like mad and shoots flames and black/dark blue smoke out the exhaust. So, its obviously running rich. The Rpms get rough and uneven if i do rev it up at any rate past feathering the accelerator. when i kill the car… its almost like it keeps running for a few cycles… just a quiet few pops comign from the exhaust and the car shakes to a stop. Any ideas?
or not, if his o2 sensor is fucked it will run rich but it wont cought and hack and not want to rev up…if you dont belive me unplug yours and let me know how its running…my silvia’s o2 sensor wasnt even wired in properly when i first bought it…and i drove it like that for 2 months with no problems…other than poor, very poor gas mileage!
Sounds like a BOV issue… basically you say that you need to feather the accelerator to not make it stutter/die. You’re only making boost when your throttle body is pinned open. Basically when you blow off you run rich momentarily and the car doesn’t seem to like that in it’s current state.
I’d recirculate it but I’d first get around to doing the headgasket.
Welp, I’ve got the car running way better, i rewired the MAF and turns out there was a shitty ground, hence, the stuttering and whatnot, i’m probably thinking my O2 sensor is going because i get IMMENSLY shitty milage. like… 40km’s per quarter tank. Have to check that out, anyone know if i can get a 02 sensor from another car instead of getting a “sr20” one. i’m guessing it would be cheaper and alot quicker to get.
any 3 wire heated o2 sensor that fit you bung will work, you just need to change the plug out. I remember reading on here someone went to a 4 wire Denso one and got way better mileage cause of it, and it was also like $80. Search for it.
Im thinking your o2 sensor is not the culprit, as it only goes into closed loop at idle. THis means that the only time it will effect anything is at idle. Once any load is applied to the engine, or RPM’s are raised, it is no longer in closed loop, and so has no effect on mileage.
Sounds like a boost leak, coupled with some other issues.
Do the headgasket NOW, before you ruin the motor.
If that doesn’t totally clear it all up (which in my oppinion it should) check your BOV for leaks. Failing that, recirculate it. 02 sesors will not cause the car to run weird usually. The most damage they will do is cause it to run rich and kill emmisions/fuel economy.
Open loop is based on both airflow and TPS%. Which ever will cause open loop first will bring the ECU into open loop. So it’s not a set speed or RPM… You can be in Open Loop at 1500 RPM’s if you are WOT…
eg. you can stay in closed loop while cruising to get better gas mileage