sig425

I just got my new fd with a brand new motor. It has a complete intake and exhaust. 3" midpipe, downpipe, exhaust. twins non sequential, large intercooler, huge streetport, 1600 cc secondaries, 550 primaries, fuel pump upgrade. Throttle body machined out with the butterfly valve removed and other mods done to it. Power FC


the o2 wideband sensor is always reading 15-18 unless I am at idle where it reads 12. Highway cruising is about 15.5 -16. When I let off the gas it almost always reads "air lean." Im no tuner, and the motor is being broken in so I have boost pretty much disabled.. But I am a little worried about these numbers. Injector duty never gets over 40 at peak. I keep the rpms under 3k and I think the rev limiter is set to 4.5k currently. If I get on the gas... the air fuel seems more in line 14-16 so I was wondering if maybe the map is not set for extreme ***** drive mode and I should stop being so careful?

The guy I bought the car from said it would need a tune after the break in but that the map should be fine for the break in period. I havnt approached the seller yet but he said if I had any issue we would work it out until after the car is tuned. He has a datalogit so we can change the map pretty easily. I think this is a modified gotham map. Should I drop in a another map? I thought it should be more like 14 across the board or even richer during break in.

thx

PhatManBUD

could be stock maps...im driving around on stock maps right now to break in my motor.


maybe it isnt a wideband o2 and is a simple narrowband gauge?

mjw

iTrader: (1)

When you let off the throttle the throttlebody plate is closing, IE there is very little air the motor is taking in, hence the injectors are not needed since the motor is not under any load.

sig425

nope, its a wideband.

sig425

Its not so much the "air lean" at decel as the numbers during running Im worried about.

mjw

iTrader: (1)

It seems a little lean to me but its hard to say since your rev limiter is set so low, your idle seems fine. The motor can take leaner conditions at lower rpm and lower boost, post a log or something so we can actually see exactly what is happening.

sig425

kewl thanks. Will do once I can get one.

twokrx7

iTrader: (1)

Those AFRs sound fine except idle is a bit rich. If you are worried, put some race gas in it and throw in some extra fuel under boost just to be safe. Start conservative and work up.

Wargasm

Correct me if I'm wrong here... Since I never use my stock O2 sensor... I have stuff set up a certain way...

A couple questions...

1 - Are you still running the stock narrowband oxygen sensor in addition to the wideband or is the stock sensor removed and the wideband is installed in its place?

2 - In your PFC setup, is the stock feedback loop enabled or disabled? As I recall, you can disable O2 feedback (closed loop). Since I never use my stock sensor, I have this disabled.


At idle, I run around 13.5:1 because I like the strong idle that this produces. It also produces a lot of stink on my clothes, but that's OK... I don't inhale. If you daily drive the car, I'd definitely get that idle more towards 14:1 or even 14.5:1 to reduce stinkage.

During ***** driving, 15:1 is OK... Your engine won't blow (as long as you're in ***** mode) though I don't recommend it. I would at least make an attempt to get it down to low 14s for cruising. 16:1 seems extreme even for cruising and if it's really spending a lot of time there, I'd be a little worried.

Any time you lift on the throttle, it will go very lean while coasting. This is normal.

*edit* One more thing... most widebands read a little differently depending on the brand. 14 on brand A might be a 14.5 on brand B. I'm running the OZ-DIY Wideband and I'm basing my comments on that.

twokrx7

iTrader: (1)

Wargasm,

I ran 16+ AFRs in cruise without issue for many moons. I like to run as lean as I can in cruise with the motor running silky smooth and then add a touch of fuel to account for days when the car needs it. I never spent much time leaning out cruise in the lower gears, like 35 mph, because the motor did not like to be very lean in the lower gears at lower speeds.

twok