1jz running lean in boost

[stevenr816]

PLEASE READ COMPLETE THREAD BEFORE REPLYING

Have done everything in the books. Idles great 14.4 - 14.7 at idle, cruise is great little richer. As soon as you get in boost it goes straigh to 10.7-11 afrs then straight to 16+ afrs to breaking up. You can hold the throttle dong a full pull at half throttle/5 psi and will run perfect 11's. The more you push the gas the leaner it goes. This is with 8psi, 12psi and 15 psi. Also you can have the AEM FIC at +100 fuel with no change.

Codes
--------
21 - oxygen sensor
We have it emulated through the innovate lc1 soothe heater singal is "open" we have ran the car with it plugged in and not

Mods
------
1jz
67mm turbo
3" turbo back
4" intake
3" fmic and piping
Synapse bov
Drewgo mani
AEM FIC
Walbro
Aeromotive FPR

Things we have changed
--------------------------
3 different known working JZZ30 ecus
With/without AEM FIC
With/without factory o2 sensor
2 different wideband spots, right of the down pipe and 1 in mid pipe
New wideband sensor
2 different walbros (1 new, 1 used)
Dropped tank to make sure it was clean
New fuel filter
Stock and DM SS feed line
Set of known working 440s
Tested and flowed 550s
With/without resistor box
AFPR and stock fpr
2 different map sensors
Have checked and watched voltages under load, all ecu powers, coil power, injector power, fuel pump power all while driving
Drivin without the coolant temp, intake temp and tps plugged in to get rid of all fuel related items.

Things we haven't changed
----------------------------
Drivin it off a cliff
Set it on fire
Coil packs
Crank/Cam sensors
Alternator
Knock sensors
Ignitor
IAT
Water temp
TPS
Starter
Complete harness

Please don't post that it's the size of the turbo or the AEM. We have a guy running the same exact turbo setup with 440s, walbro, 15psi and holds 11s to redline with no tuner. Also have tuned multiple 1jzs with the aems with no problems.

 

[MINA]

i might be wrong but sound like the wide bands sensor is crapping out did the same thing on my STi the second i wot it leanded out.
now dose it stay lean or dose the gauge blank out?

 

[stevenr816]

It goes lean then breaks up from being lean anywhere from 16-18afr nothing more then that. Flat lines off throttle, has fast response time, new sensor.

Unless it's really not lean and loosing spark so makes it look lean.

Btw it's a innovate lc1 and never looses signal while data logging.

 

[MINA]

ever get those injector flow tested

 

[gurley0916]

ever get those injector flow tested

PLEASE READ COMPLETE THREAD BEFORE REPLYING

Set of known working 440s
Tested and flowed 550s

 

[S.A. supra]

Try new coil packs. It worked for me. It didn't make sense to me but someone explained it as a miss fire that confuses the wide band.

 

[Dirgle]

This is possible. If the Coils are not getting hot enough to jump the gap it won't start the combustion process. This means the oxygen and fuel inside that cylinder is not used up and will register on a wideband as lean. The sensor is only designed to detect oxygen, not fuel. So even though the unburnt fuel is there also it only sees the oxygen.

Check your coil pack housings for cracks, including along the spark plug stalk. Typically when a coil goes bad this is where it happens. A crack in the coil pack might not allow a spark under light loads but when load increases it becomes easier to jump that gap than the one between the spark plug.

 

[Albert]

There was a small crack on one but we shrink wraped them. With no change. I'll verify with my buddys coils that are in know working order.

 

[CyFi6]

You also need to watch your fuel pressure as you go WOT and it leans out, to make sure your pressure isn't dropping off.

 

[Albert]

Checked that. With the aeromotive then tried the stock fpr. No change.
I ended up blowing up the diaphram after taking it off and putting 120psi thru it. So I'll pick up the $25 rebuild kit so I can slap that back on so I can watch it some more.

 

[mk3tattoos]

did you do the 12v mod or are you running the stock relay and resister?

 

[West0n]

I think its the size of the turbo... or maybe the AEM

 

[Albert]

yes. The 12v mod was done through the harness. The fuel pump kicks on when you throw the key to ACC. I'm getting 12.4 Volts off the plug in the trunk.

Rofl Wes get out of here!!

 

[kamikazemkiii]

How many volts are you gettin in boost?

 

[Albert]

Same readings practically. Maybe a .2 drop

 

[stevenr816]

All powers we've checked are 12.5+ with a .1-.2 volt drop with full load

I think its the size of the turbo... or maybe the AEM

HI!!!!!
What's your name? You could be right?? Any more info

 

[hvyman]

Whats your spark plug gap?

 

[mkiiichip]

Concerning Fuel pressure,

Checked that. With the aeromotive then tried the stock fpr. No change.

Were you able to watch the pressure while it was going lean?

 

[stevenr816]

Whats your spark plug gap?

We've done .028 and .025 with NGK BKR7E's and 3330's

Concerning Fuel pressure,


Were you able to watch the pressure while it was going lean?

We've done multiple things with fuel pressure.
550s @ 40psi AEM FIC
550s @ 18psi stock computer (fuel pressure to make them 370s)
440s @ stock fpr
We moved the gauge inside but that's when we tested the diaphram to see if it leaked and popped it. So don't know boost fuel pressure yet or if it's dropping off.

Ordered a diaphram so once that comes in we will know

 

[OneJArpus]

Do you have the stock fuel damper?


12v mod, is it normal to see 12.x? I see 13.x (what ever my alternator is charging at). Shouldn't it be a little higher?

When does the misfire happen? Full throttle? Partial? In boost? Going into boost? Cruise? Low RPM? High RPM? Does it happen in neutral?