renegade_ewok

Trying to diagnose this issue as its just kind of annoying right now. Heres all mods basically that could be relevant...

- Nismo 555cc injectors
-300zx mafs
-Jim wolf retuned ECU - chipped for injectors/maf
-Greddy Intake, FMIC, BOV (vented)
-3" TBE
-HKS Step 2 Cams 264/272
-300zx Throttle Body
-Turbo XS Manual Boost Controller

Essentially what happens when I drive around in the 2000-2500 RPM range before I hit boost, on partial throttle, is some bogging/hesitation. The car will just feel like it is hesitating and won't feel linear. It will buck a tad too. If I let off the gas and get back on it, it is cleared up usually or if I get on the gas hard and hit a few psi of boost it clears it up significantly. Sometimes it never happens, sometimes it happens every gear but as soon as I get past 2500 the hesitation never exists.

Car was run at 10-15 psi and it exists at any boost level.

My first guess was that this would be the vented BOV richening the car out and making it bog... am I right in that assumption? I know throwing a wideband on the car would basically tell me if I was right or wrong, but I don't have one of those nor the money for it. Should I get someone to recirc the BOV for me and see if that solves the issue or could it just be a shitty tune? Don't know how good the jim wolf tunes are as I bought the car with it.

i3litzace

I am having similar problems with my s14 sr20det. Keep me posted i want to know how this gets resolved. The only difference is that i would get back-fire through the exhaust when i upshift.

when i checked the factory service manual it said to check spark plugs first then check the heated O2 sensor and canister purge whatever that is. last step is to check for air intake leaks. i just got my spark plugs and while i go in there im going to check my coil packs for problems and check for leaks and the type of fouling im getting.

If the spark plugs and coil packs are good then im going to check my injectors and o rings for leaks...

If anyone has had similar problems or solutions let me know

renegade_ewok

I get backfire when I drive around too. I've spit hardcore flames before just granny shifting and on rare occasions sounds like a weak gunshot. It has happened to me at night before and I see a flash of light behind me which basically told me that the car is running rich.

My guess is spark plugs are fucked, weak spark = late ignition which could shoot not fully burnt fuel out of the motor which could cause the flames. Gonna stick some ngk iridiums in there when I get the chance. I haven't driven the car much but in all honesty my best guess would be a combination of BOV and fouled plugs. BOV not fully closed pre-boost (which makes sense since when I mash on it at like 2100 and hit 2-3psi it stops hesitating) and the spark plugs causing the hesitation once I hit WOT/full boost (haven't done it much after it started happening).

fcdrifter20

the esiest way to find out, like u said is with a wide band.specialy scince ur running higher boost. but u realy cant do to much till u get one of those. no use in messing with settings till u kno wich way a/f ratio is goin. recirculating the bov might help, ur assumption sounds pretty pheasable to me. but wide band is a must once u start altering the stock engine for better performance