Mortify

I have a 93 Speed density car, and on a roadtrip recently my car must have passed through michigans "bermuda triangle" because my o2 sensor harness ripped off (both of them!) and i developed a loud and annoying exhaust leak on my front passenger side primary so I was stuck getting crappy mileage in "limp mode" all the way home.

The fiber part of the gasket has burnt away, need a new exhaust gasket?
Is there a way to tune out o2 sensors at pcmforless?

Josh3111

I had mine tuned out, pcmforless can't do it, but if you take it to a good tuner it can be done.

IrocSS85

yeah you should get a dynotune for a good "openloop" tune.

96ZCamaro

Would an open loop tune end up being just as good as one that goes into closed loop?

Mortify

why wouldnt pcmforless be able to tune it out?

96ZCamaro

The reason I beleive that they would not be able to is because they will not beable to tell what your A/F mixture is without actualy having it on a dyno. And if they do not have that information it is pretty much guess and check on your tune.

Mortify

wouldnt they be able to pre-set a a/f ratio or do the o2 sensors provide that feedback to reach the proper a:f? I just dont want the chance of my harness ripping off again if I have to buy a new one...

96ZCamaro

Yea the o2's set up kinda like a base line for the computer to go off of to set the right amount of fuel into the engine. But on a dyno they can read the exhaust gases without the use of the origional o2 sensors so that they can set the computer for the right mixture.

Mortify

I dont have a dyno anywhere near where I am... and im affraid of my harnesses ripping off again... they wouldnt be able to lets say tune for "well at these rpms and this throttle position we put <insert a:f>"

96ZCamaro

You might end up having to try and find one and call them up to talk to them. They would be able to tell ya better then anybody else can.

IrocSS85

damn, for some reason my response earlier didnt take.
but no, they'd be totally guessing. so its alot harder for them to get it close enough to be reliable with a mailorder tune. and yes, the 02 sensors are the feedback. the tune sets the baseline, and the pcm, once closed loop is entered, reads the 02 sensors and makes fine tune adj. to the inj.s PMW (time open) to add or take away fuel to hit a desired afr. so with out the 02's, it has to be initially setup on a dyno, (or atleast a road tune) with wideband 02sensors in the exh. to read real time to make the tune right.

Ken95Z28

No O2's here either, took many tunes to get mine dialed in right for the entire season of racing. We look at IAT and set the AFR from that. I have a Dynojet Wideband in the car that we can log the runs and make adjustment if necessary. Just remember once you get it dyno tuned for that day and the temps go up or down that the performance could take a hit as well.

96flame

Ever hear of tie straps? Fasten the harness and you'll never have a problem. Eliminating O2's on a street driven car would be like playing with fire. You'd need to tune under all load conditions and all temperatures. Fix the harness and call it a day.

Mortify

Oh man, the harnesses are gone... I guess I'm going to just look for the o2 wire and use some shrink wrap on it... Would running super rich cause o2 sensors to fail? Where would I definitely find the start of the o2 wire on a 93 car? (What location in the engine bay)

2000GTP

Yes, running super rich can damage the 02 sensors.