3.20 volts on my 0/2

[5sp. mini]

i have been watching my 0/2 volts on my otc 4000e scanner. when cold it starts at 1.90 volts then starts to drop once it starts to warm up it will switch good but under wot i will get volts of 3.20or higher then back down to under 1.0 switching lean and rich, i,m not fouling plugs and i get 23 mpg. but i thought the 0/2 volts didnot go over 1.00 volt?also at wot map volts will go up to 4.74 before cutout which it does not hit g vavle set just right. do you think thats norm. or maybe bad inj. set up is 88 2.2 in 89 mini running 2.5 inj. and stock 2.5 ecm has a mopar 0/2, 3inch ext. new stock carter fuel pump with 3/8 feedline/5/16 return. i have no real reson to think there to much fuel but at 2.00 volts or up theres no knock or retrard . i have 2.2 t1 inj. that i can install what do you guys think? run it as it is or swap. there a power band that i think i,m missing because of too much fuel. AL

[Tony Hanna]

Sounds like a goofy O2 sensor to me. The map sounds normal as there will always be some varience with mass produced electronics. That's why people that use zener diodes often have to try a few of them before finding one that works.
My main concern with your setup is running a 2.2 on 2.5 electronics. It will work, but you're gonna be over-fueling and the timing is going to be all wrong.
My advice is to swap in an '88 2.2 SMEC and go from there.
HTH,

[turbovanman²]

Its the scanner. My Snap On and OTC read funny like that. I bet some of your other readings are also out, IE RPM, coolant temp. I get asked what computer I have, and sometimes you need to trick it with a different model, engine code etc. Once I get the right combo, it reads perfect.

[5sp. mini]

i swaped the 97 pathfinder cartridge seem to make a diff. till i stop to take a piss then upon restart had reading of 5.02 volts WTF then as i got on xway it when back to under 1.00 volt and was switching great but when at 5.02 it still was not blowing black smoke . was going to swap my 88daytona t2 smec but it started up and did not feel like resetting the radio so i clean up around my garage for a while. lazy ya. funny the 93 cartridge i have to restart each time but the 97 one comes right up to where it was before the van was turned off.funny thing it will start to break loose at 4500 rpm so i shift. al

[sergio]

You need to determine if your o2 sensor is really putting those voltages out... get a multimeter on that output dude. The sensor shouldn't go over 1V.

[5sp. mini]

read it from the output wire right. it has a mopar reman semc. i do have a spare semc to try, my 0/2 is only 6months old and it,s a new mopar one.cleaning up helped looked like a used car lot. don,t want zoneing to get on me . AL

[turbovanman²]

Theres no way it can put out 5 volts, even if it screws up.

[5sp. mini]

thats what i thought but it said 5.02 on the scanner. al

[turbovanman²]

thats what i thought but it said 5.02 on the scanner. al

Like I said, your having a software issue,

[Tony Hanna]

Theres no way it can put out 5 volts, even if it screws up.

No way you could get some voltage leaking from the heater 12v+ to the signal output? Maybe a piece of carbon where it shouldn't be?

[5sp. mini]

i will read with a volt meter friday unless my snap on meter is not working to / just like to make sure there is fuel there i don,t like 10psi only 14.5 ya. al

[turbovanman²]

No way you could get some voltage leaking from the heater 12v+ to the signal output? Maybe a piece of carbon where it shouldn't be?

Nope, seperate circuits and per chance if there was some leaking, it would leak 12 volts. There would be a whole lot of ECM frying going on, I have never ever seen it or heard of that happening,

[Tony Hanna]

per chance if there was some leaking, it would leak 12 volts.

Not necessairly. Remember, carbon traces are what they use for resistance in potentiometers like TPS and such. I'd say voltage would depend alot on the distance across the short if it was caused by carbon. The longer the path through the carbon, the lower the voltage...
You're right though, that probably isn't the problem. If it was somehow leaking voltage from the heater, it would likely stay constant instead of only happening at startup.