do i not need a tune? header install

[GBarnes67]

Well I've been a member for quite a while but I don't like to post too often and I apologize if it is in the wrong section. I just like to read. But I have a question that I don't think anyone I usually consult can answer. So I bought my 2v gt with a kenne bell supercharger installed by previous owner. It also had a cat back bassani exhaust. Since then I changed the exhaust and no codes came up after removing cats. Now I just installed long tube headers yesterday and I didn't have the o2 extenders so the guy that did the work told me it would drive funny without the o2 sensors plugged in but I drove it about 60 miles and no engine code came up running open headers and no o2 sensors plugged in.

Could the tune that was on the car when I bought it have bypassed the o2 sensors?

 

[Joey8]

Maybe the cats were gutted and he had the o2s turned off?

 

[01yellercobra]

Are you talking about the front or rear O2's? It's possible to turn the rears off with no ill affect. If the fronts are turned off the car will run rough. Unless the computer has been forced into open loop full time. Which I can't see a good tuner doing.

 

[GBarnes67]

Sorry guys I've been doing a lot of work at school and haven't checked in a while. But all o2 sensors are disconnected and Joey, the cats were good when I took them off. I talked to another mechanic and he said the tune installed after the kenne bell might have bypassed the o2's all together.

 

[DSG2NV03]

Yea not a good idea to have the front O2 sensors turned off.

 

[Yellazxr]

Sorry guys I've been doing a lot of work at school and haven't checked in a while. But all o2 sensors are disconnected and Joey, the cats were good when I took them off. I talked to another mechanic and he said the tune installed after the kenne bell might have bypassed the o2's all together.

I refuse to believe that you're driving the car around with the front O2 sensors disconnected and it isn't running horrible.

 

[32vApe]

With the front o2 sensors unplugged, it will run open loop all the time. If the fuel trims were within 5% with the sensors plugged in, the car will run fine in open loop. I run my car this way, no o2 sensors at all. I just tuned in the maf curve to run 14.5:1 cruise and 11:5 wot. If you are not getting a cel, then either the bulb is burnt out or the tune has all the o2 sensors shut off and the car has an open loop tune. And yes if you added long tubes, it should be retuned.