[Escort97Sport]

Ok, new to this, i run a 97 SPI 5spd escort as a 4cyl race car, i had a new 2 1/4" exhaust made for it from the manifold to the rear tire, and i forgot to tell him to put the bung in for the 02. Ive been running it for 3 weeks now but each time its been getting slower and slower in lap times with the same setup on. Does not having an O2 cause problems, i would imagine it does but i'm not sure about anything. Let me know thanks.

 

[GregF422]

Not having the upstream O2 sensor WILL cause problems with mixture. The downstream isn't really that big of a deal. It just tells the computer if the cat is working or not.

 

[97DragScort]

reset your ECU and make sure your not running rich - the ecu will try to constantly find STOICH and if your rich, your power will degrade, more so over time.

A fresh car tune is like a Windows install.. in 15 minutes, theyre both obsolete.

 

[me19875]

yea the power loss you're feeling is probably the computer adjusting the long term fuel trim. if you reset the ecu and the power comes back, that would support that theory.

 

[Escort97Sport]

Ok, shes not running rich so should i just disconnect the computer or is there a special way to do it?

 

[Escort97Sport]

and yes it is the downstream O2

 

[celery952]

1 vote for disconnecting the computer

 

[Escort97Sport]

well did it and it seems like it idles a lot better and feels a lot smoother through the powerl. Thanks guys.

 

[me19875]

o yea, it's the downstream... in that case i would agree with greg. what it's supposed to be used for is only to tell if the cat is working or not, but your computer might do weird things if it thinks the sensor is bad.

 

[Escort97Sport]

yea, not to mention, the gas was 6 months old in the thing, some 110 octane and shes running awesome now. I bought a new one from autopart international, just need to get a bung welded in so I can put it in.

 

[96projectescort]

ok let me get this straight im having a similar problem my car seems to be running real rich so from what im reading is that my 02 sensor befor the cat??