Cobra swap tuning issues

[zacmustang03]

Hey there guys been a while since I posted anything in here. So my 2003 swap is complete and getting tuned. The tuner has run into an issue with my o2 sensors. He says there reading inconsistent and all over one minute there good the next there all over. Both sensors are new and so is the harness. Cars mods are

Posi Ported eaton 2.8 upper
2lb lower
Lfp throttle body
Lfp heat exchanger
60lb injectors
Cobra hat with duel walbaro 255lph
Duel fpdm
High boost cold air
2.5 in mac cat back
O/R x pipe
Egr delete
Rear o2 delete

I was looking for 500rwhp
The car is running fine when tuned in closed loop. But when he uses the sensors it goes all to hell. Any help would be appreciated thanks

 

[zacmustang03]

here is the car

 

[Mystic03]

Are they oe sensors or bosch?

 

[zacmustang03]

Bosch

 

[Oiljunkie]

Who's tuning it? I'm doing the same swap right now, just waiting on my engine to get back from the machine shop so i can start finishing up.

That looks like the Bays at Stealth Performance.

 

[zacmustang03]

Ccmr performance in spruce grove alberta.

 

[03Steve]

Make sure they aren't crossed; i.e. driver to passenger / passenger to driver. Make sure there are no exhaust leaks. Make sure the engine compression is good.

In the meantime, there is no problem running the car in open loop (without oxygen sensors) 100% of the time. I have done it for four years now in my car.

 

[Ourobos]

Why not tune the O2 sensors OUT of the equation? If you're burning a chip, there is no need for them with a good tune. They use their wideband to tune it and turn yours off totally.

 

[slonech]

do you have long tubes or stock exhaust manifolds?

 

[Mystic03]

Bosch

Thats your problem had same issue with mine couldnt figure out why pulled the 02s and they were bosch get some oe for the upstream the honeycomb style work way better and faster than the zirconi slit stlye

 

[zacmustang03]

Okay ill do that man . Thank you

 

[zacmustang03]

do you have long tubes or stock exhaust manifolds?

Stock manifolds

 

[zacmustang03]

Why not tune the O2 sensors OUT of the equation? If you're burning a chip, there is no need for them with a good tune. They use their wideband to tune it and turn yours off totally.

Ya he said he can do that he just likes to use them for fuel mileage and smoother midrange I guess

 

[zacmustang03]

Make sure they aren't crossed; i.e. driver to passenger / passenger to driver. Make sure there are no exhaust leaks. Make sure the engine compression is good.

In the meantime, there is no problem running the car in open loop (without oxygen sensors) 100% of the time. I have done it for four years now in my car.

They very well could be crossed I bought a new harness and that could be the issue I guess as well

 

[zacmustang03]

Make sure they aren't crossed; i.e. driver to passenger / passenger to driver. Make sure there are no exhaust leaks. Make sure the engine compression is good.

In the meantime, there is no problem running the car in open loop (without oxygen sensors) 100% of the time. I have done it for four years now in my car.

How does your car run as far as part throttle etc. Did you suffer alot on the fuel consumption side?

 

[03Steve]

My car runs well at all throttle positions. Best range I ever recorded was on a long road trip. 354 miles, one tank, open loop.

 

[cj428mach]

OP I wouldn't run my car in open loop. Its not that heavily modded that you should have tune issues.

 

[zacmustang03]

OP I wouldn't run my car in open loop. Its not that heavily modded that you should have tune issues.

You wouldn't or would lol

 

[zacmustang03]

My car runs well at all throttle positions. Best range I ever recorded was on a long road trip. 354 miles, one tank, open loop.

Okay that seems just fine with me then

 

[MalcolmV8]

Make sure they aren't crossed; i.e. driver to passenger / passenger to driver. Make sure there are no exhaust leaks. Make sure the engine compression is good.

In the meantime, there is no problem running the car in open loop (without oxygen sensors) 100% of the time. I have done it for four years now in my car.

I noticed when running my car in open loop the canister purge solenoid doesn't open releasing pressure from the tank. When driving long periods of time like daily driving you'd get a bit of fuel smell at times as the pressure built up enough in the tank to blow vapor out the vent hose by the filler cap.