02 voltage

[32PSI.]

I have a problem with 02 voltage dropping at wot it is around 250 I am running 43 psi on the fuel with vaccum line off 50lbs injectors with a 52 turbo and translator please help also it has no knock

 

[Rob B]

Have you tried replacing the 02 sensor? Running leaded fuel can kill an 02 sensor real quick. That is, if you run leaded fuel... If it's old and crusty, probabally needs replacing anyway.

Also it wouldn't be a bad idea to run a EGT sensor. Better tuning can be done with one than just 02 readings. My friend who runs one has seen some wild 02 readings, while the EGT sensor is reading a perfect number.

 

[Quick6'n'-K.C.]

Originally posted by 32PSI.
I have a problem with 02 voltage dropping at wot it is around 250 I am running 43 psi on the fuel with vaccum line off 50lbs injectors with a 52 turbo and translator please help also it has no knock

ahh yeah the ole- non grounded harness-

on the passenger side head, back by the firewall, there should be 2 ILETS with 4-6 ground wires .. that bolt to the back of the head.
if these wires are not grounded, then your 02s will fall continuously to about 200 MV at WOT-

im guessing when someone pulled the head off, they didnt put the bolt back in cause it is a PITA-

the easiest way to reground those is if you have steel heads, just go ahead and make the passenger rear intake bolt into a stud, and ground them there just like they did on the TTA.
HTH

LET US KNOW HOW IT TURNS OUT

 

[32PSI.]

all the grounds are connected

 

[WSLN 6]

Anything lower than 750 is too lean and your motor WILL knock if the sensor is actually accurate.
Slap a new Ac delco O2 in there and go for another rip.

 

[Turbojorge]

Originally posted by WSLN 6
Anything lower than 750 is too lean and your motor WILL knock if the sensor is actually accurate.

Not Necessarily. Rememeber, 02 sensors aren't very accurate above .70 themselves. Yes, .75 is a baseline of where you want to be, but every car is different. EGT will really tell you how rich or lean it is.

I agree with swapping the 02 sensor out. If you run lots of race fuel, I'd suggest a heated 02 (AFS 74) from Delco.

 

[Quick6'n'-K.C.]

ok-
no knock
250 MV at wot

let me guess, it starts out at 700 or something and just keeps falling down to the lowest possible number?

did you double check to see if those wires are grounded?
do you have steel heads or aluminum heads?