Dadic 78

Trying to help a buddy here...

His LT1 is running rough, I got him to scan it (with Datamaster) and he got the following codes:

Hi-Res Fail
Left o2 Fail
Right o2 Fail

The o2 Sensors were just replaced in the car, so I told him to check the wiring, make sure none of them burnt on headers etc...

I'm not familiar with Hi-Res Fail. I know Lo-Res Fail means it's time to go Opti-shopping. Does the same apply with Hi-Res Fail?

Thanks guys!

1997whitez28

Are the o2's ACDELCO or Bosch? If you use any other brand or universal you may have problems.

mrmint69

Maybe the wrong type were used or not hooked up correctly.

lt1loudmouth07

Hi-Res Fail is your optical sensor in the Optispark make sure u check the opti harness to make sure its ok before u change it out. I had that problem 100 times. just stay away from ebay cheap opti's

Injuneer

What were the exact codes for the O2 sensors? What year is the car?

Clear the codes (pull "PCM BAT" fuse for 30 seconds) and see how fast the Opti high res pulse code comes back. Loss of high res code won't affect the engine operation too much, just increasing spark scatter slightly.