Brand new o2 causing all my problems?

[Enano]

So heres my problem:

Previously I had a check engine light on due to o2 being bad. No problem, got a new one and CEL went away.

With both o2 sensors, the car would randomly at any given time, run full lean at idle, cruise, light throttle, and would go away ONLY if i stepped on the gas to the floor.

With the o2 connected, and when it wasnt at full lean, the car would run at 12.5 average at cruise and depending on how it felt would run at 14.7-15.4 OR 11-12.5. It would also have massive hiccups under load and under boost. (The wideband would go full lean when they would happen)

Also a major point, my fuel cut would vary. It would be at 16 psi a whole day and then the next day id be able to boost 20 lbs.

Well today i disconnected only the blue wire from the o2 and now CEL IS BACK. But it runs fucking amazing and it never goes full lean and hiccups are gone.

SO WTF???

Edit:
560cc evo injs
57 trim
3 inch all the way
Timing at 10
Tps adjusted per TSRM
NO CODES
Walbro 255
Lex afm
Egr delete
Stock fpr

 

[BryanDyer]

Lol CEL is back but no codes...

 

[hvyman]

You have 560s, lex, stock ecu and no egr and nothing to tune with..

what wideband are you using?

also not sure why you decieded to just remove a wire from the o2.

And yes it is possible to get a bad part right out of the box esp if its a cheap part.

 

[jetjock]

Lol CEL is back but no codes...

^ This. Not to mention the O2 sensor can't have anything to do with his problems...

 

[IndigoMKII]

EGR deletes don't increase horsepower, just so you know, the EGR is fully closed at WOT. It does cause lean conditions though because you removed an item the stock ECU is tuned for so with the exhaust gases not passing back through the chamber.

Also, 560cc injectors with a walbro 255 on stock fpr should be running like 9.0 rich WOT.

 

[Enano]

Got a code 22 (coolant temp sensor), I said didn't have any codes because the CEL being on was due to the o2 being disconnected, so other than the o2 code, I didnt have any. Now I do though.

Using an AEM UEGO and brand new o2 was ordered from driftmotion.

I randomly disconnected the blue wire from the o2 because I remember the car running alot better without lean issues when I didn't have a working one and I was right. The car is running alot better. In fact, just yesterday I did a test. The car was idling nicely at 14.7 and I connected the blue wire and it went full lean. Disconnected and it went back to 14.7 after a small rev.

I know I should be running rich, but why am I hitting fuel cut randomly at random psi and having those misfires.

Coilpacks checked per TSRM and are good, all wiring seems to be good. Getting 12v to coilpacks as well.

Plugs are NGK coppers one step colder and wires are NGK. All new. Also had same issue with NGK iridiums one step colder.

BTW: I would rather not have hot ass exhaust gasses trapped behind cyl 6 while going WOT, possible exhaust and vacuum leaks, as well as a clusterfuck in my bay. To each their own.

 

[hvyman]

It actually runs hotter without egr. Its been proven with a temp gun.

 

[Nick M]

I know I should be running rich, but why am I hitting fuel cut randomly at random psi and having those misfires.

There is no correlation between running rich and fuel cut. Fuel cut happens because the airflow meter signal is fast enough (Hz) that the computer thinks you are too lean and as such the injection is halted to prevent engine damage. You could be "pig rich" and hit fuel cut.

 

[IndigoMKII]

If you think the egr causes damage then I suggest you find a thread I started called egr or no egr.

Im not sure about you but I dont like lean conditions under part throttle but to each their own.

 

[BryanDyer]

it can't be the O2 because the O2 sensor doesn't even function past 70% throttle anyways. Are you sure you have no codes like code 52 maybe? Code 52 can cause some of your symptoms as well as 51 if your TPS is off.

 

[Enano]

I have no codes. Fixed code 22 today. As for the issues, misfires under boost and load at random times. If i connect the o2 car will run lean at random times. Not going to argue with your about egr cause it doesnt really matter to me or help me with my problem.

 

[Enano]

When the lean issue happens at random times the timing goes retarded (checked it with a timing light) it goes above 15

And the car runs like shit of course (bogs, misfires, tries to stall and will stall if i dont give it gas

 

[Nick M]

What Hz does the airflow meter show at idle?

 

[IndigoMKII]

Of course when it goes lean it'll pull timing.

Also, did you even read up on what the egr does for the system? Cooler rear cylinder egts, better mpg, no light throttle pinging (going lean under part throttle aka climbing hills) and for the best part, no hinderance on performance at all if its functioning properly.

If you want to remove the egr, swap to a jdm ecu to save yourself the headache.

 

[Enano]

I dont know what Hz it shows. How do i check that while the car is on? And I already removed egr so no going back lol

 

[Nick M]

Pie