nismo2trd

ill make it simple. i have a stock 1jz, greddy fmic, and im running on usdm 93 2jzgte plugs, O2 is not hooked up. no vaccum leak. while my engine is cold. boosts good at WOT.. after the engine's warmed up. everytime at WOT it bogs when it hits boost. but if i slightly tap on the pedal to reach full boost, no problem what so ever. im thinkin could it be my plugs thats causing this?

qksl2

CTS






Ian

vipsoarer

hook an o2 sensor up and it should clear it up some, if not fix it completely

19psi

why woud you not run an 02 sensor? that's silly, the ecu has no idea what's going on. of course at wot, it doesnt' matter, because then the ecu doenst use the 02 sensor for feedback. but before that, you may be getting too rich before wot causing the bogging.

qksl2

The o2 sensor does not do anything under WOT.

However, an o2 sensor will help your closed loop performance.

Ian

vipsoarer

19psi: thats what I was thinking also which will inturn affect timing and can cause the WOT to act up also.

2jzlex

iTrader: (3)

I think you are missing the point.... There are two modes for stock ecu, closed and open loop. Open loop gathers information from various sensors (i.e., 02 sensor being one of the major contributors) and calibrates for best fuel economy, driveability, etc. In closed loop, fuel and timing are adjusted by RPM and preset map areas specifically for the get up and go. So what is happening is, under WOT, the car doesnt need the 02 sensor, hence the good pull. Under light load, while its still in open loop, your ecu cannot read a narrowband AFR range to calibrate fuel delivery because there is no signal from the 02. Your timing is kind of a sidenote, not really relevant in this case. You need to hook up an 02 sensor if you are on stock ECU with no fuel management.

Jon

vipsoarer

2jzlex: i understand what your saying as I understand closed vs. open loop modes along with the maps that are used. the thing that I am trying to help with is why it bogs when warm and only when it hits boost. I am trying to remove all the extra variables that may be affecting the in-boost factor. That is all. Obviously the info that he gave us is incomplete since it doesnt give anything but what is happening and under what conditions giving no info as to what parts (stock vs. aftermarket) any tuning etc.

I am just wondering how at WOT not in boost its good then in boost its not... maybe plugs... maybe plug gap... i dont know Im just trying to help the guy out.

19psi

well lets think about this. engine cold, closed loop= rich condition. full boost at engine cold, richer than normal, runs fine.
engine warm, closed loop but no longer rich from cold start, wot, bogging. i'd say he's going lean. man i hate dealing with tuning issues without any datalogging. a wideband would tell us what we need to know very quickly.

2jzlex

iTrader: (3)

My repsonse was not directed at you.... It was directed at the comments about affecting timing and whatever else he said. What I was trying to say was nismo2rd 's repsonse to what you said had little to do with what you were trying to explain to him. I was agreeing with you and just trying to explain further to nismo2rd. Sorry about that mixup.

Jon

vipsoarer

ahh, my bad then also. Either way, I'm thinking that in addition to the O2 sensor the other things to check should be:

1. plugs (gap and condition)
2. timing
3. coils
4. charge pipes for leaks

after that im at a loss... nismo get back to us with what you have tried and the results.

nismo2trd

...ok heres the deal. ill hook up the o2 tomorrow. condition of the plugs are good... can i run usdm 2jzgte ngk plugs with the 1jz..... i havent touched timing, i just bought the motor and dropped it in. ill double check the coils tomorrow... no vaccum leaks at all. can it be the tps?

nismo2trd

whats a CTS?

Kamronman

Hey did you ever get this figured out!?