While installing my headers this weekend, I ran the car with open headers and w/o an O2 sensor for a little while. I let it idle, then drove it around, then let it idle some more (I let it warm up to almost 200 - it was warm out today in the midwest), but no SES light!

My computer spits out code 32s (I have my EGR off temporarily) every once in a while and the field service mode w/SES light works, etc. - so, why doesn't it care that I'm running with no O2 sensor?

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Joel Geerling
Red 91 Formula, 305 TBI
Edelbrock 14x3 open element
TBI 1/2" spacer
Hypertech street chip
Crank/Alt Pulleys
180* stat
Hedman hedders, 3" cat, Hooker catback

 

Anyone? Should there be a quick SES with no O2 sensor? Everything is fine now (exhaust and O2 sensor on), but I'm just curious...

[This message has been edited by Joel Geerling (edited December 04, 2001).]

 

how long did u drive the car for?

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- David
88' GTA 5.7L TPI MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass, Gutted CAT, Flowmaster 80 Series Muffler added to Unkown CatBack, Ported Intake

http://www.geocities.com/david_angel_16

 

It idled for ~4 min, then I drove for about the same, then I let it idle a couple minutes more.

 

Was the sensor unplugged or was it just not screwed into the header?
bsa

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"If they do not run, Then they will die." - Stonewall Jackson
#3
'87 IROC, 355 TPI, Converted to SD, 700R4, B&M Megashifter, 3.42, Trick Flow Twisted Wedge Heads, Edelbrock Intake, Accel Runners, Comp Cam, Crane Gold rockers, Lucas 24# injectors, Edelbrock headers, Flowmaster 3'' exhaust, Mallory Ignition, Shift Kit, Corvette Servo, 2,000 Stall Torque Converter

1991 RS, 305 TBI, T-5, Bone stock daily driver.

 

the ecm in some of the third gen are kind of slow my car has not had an egr valve for a year never a code i would not worry to much you will know by drivability if o2 is not working properly

 

The sensor was completely out and unplugged (to make a long story short, I took the driver's side header to an exhaust shop, where the guy charged me $7 to weld in the bung I provided him with, but he welded it a a bad angle, such that the O2 sensor was hitting the crossmember and keeping the header from going in all the way... sooo, I had to seal that bung with a sealed pipe plug. Later I had a new bung welded in).

Driveability seems OK (and grounding the OBD diagnostic leads now gives the closed loop fast flashing now), but should I be concerned that the ECM isn't really using the O2 sensor if it didn't even care when it was gone?