eliminating o2 probs, 95 legacy

[MilesFox]

somy 263,000 mile legacy has a check engn lite. obd2 scanner calls for ccam angle sensor and o2 sensors.

 

i am not worried abotu the cam angle, since a wiggle under the hood will make it start if the car acts up...

 

anyway my exhaust is holloed out. i have read that the 1st sensor reads the mixture and the 2n monitors the cats.

 

i have also read about spark plug anti-foulers.

 

now here is the real question i am asking

 

would it eliminate the 2nd o2 sensor if i swapped in an ecu from a 91 legacy sedan? how would the 1st gen legacy ecu differ from that of a 95?(power maps, etc)

 

i have the earlier ecu left over from an attempted ea>ej swap, and since obd1 motors can be swapped in place of obd 2's , then this is why i am asking this question.

 

EDIT: might i add my car is manual transmission, no EGR. the spare ecu is a 91 fwd 4eat

[MilesFox]

BUMP, i said..

[nipper]

If your going to own a car, you sometimes need to put money into it. The cam angle sensor actually runs the car. Wiggling it, eventually it will break.

 

The 91 is an OBD1, where as the 95 is an OBD. Tats sort of like putting pentium 3 chip in a an old dos machine. It aint going to happen, and it isnt going to work, period.

 

If you have no cats, the o2 sensors will always read too rich, even if they are new. I am assuming holed out means gutted. It doesnt matter if the car has new o2 sensors or not.

 

Since you don't really seem to care what the CEL is telling you, why dont you just remove the bulb and be on your way.

 

O2 sensors are the heart of the fuel injection system. Without them the car runs in open loop, using pre defined parameters to make the car run. This cuts performance and gas mileage. With functioining O2 senros the car goes into closed loop, and then adjusts things for peak performance.

 

Engines can be swaped, they are only bolt patterns that limit this, unlike emission controls,wiring and sensors.

 

nipper

[Skip]

"If you have no cats, the o2 sensors

will always read too rich, even if they are new. "

 

I don't think this is true in an OBD I car

with only one 02 sensor.

 

The sensor still heats up, puttting it in closed loop,

and sends info about the 02

content to the ECU - cat or no cat behind it.

 

Possibly Miles wants this situation?

Where the ECU stll adjusts the mixture based

on info from the single 02 sensor.

 

I do agree without changing perhaps the intake and

all the sensors that it would work properly.

[johnceggleston]

ok, here's my dumb question of the day, hopefully the only one, i thought 95 leg only had one o2 sensor???

[MilesFox]

If your going to own a car, you sometimes need to put money into it. The cam angle sensor actually runs the car. Wiggling it, eventually it will break.

 

 

nipper

 

come on man, who do you think you are replying to..

 

anyway ihave already bought new struts and brakes and replaced the transmission and have new tire.....so on so dont giive me that

 

wha ti DONT want to do is go spend over a hundred dollars in o2 densors knowing it will do me no good.

 

HOWEVER, i do have the ecu and was just wondering if it would work. otherwise there are spark plug anti foulers the WRX folks use on catless downpipes, and i'm sure some resistor could be installed to fool the ecu into a proper mixture

 

i can live withthe check engine light, and i am very intimate with my CAS so no, its not about to break off at this moment. (it acts up usually from a warm start within 30 min of parking, one out of every 4 warm starts.) i have already priced that but i'll go buy it when it really gets bad.

 

what i would rather not live with is 20mpg when the car can do better, hence my question

 

so if i have to trick the o2 then it would be easier to trick only one.

 

thank you skip, that answers part of my question. i guess the other half of my question will be answered if i plug in the ecu and see if the car runs

 

any one else?

[The Dude]

somy 263,000 mile legacy has a check engn lite. obd2 scanner calls for ccam angle sensor and o2 sensors.

 

i am not worried abotu the cam angle, since a wiggle under the hood will make it start if the car acts up...

 

anyway my exhaust is holloed out. i have read that the 1st sensor reads the mixture and the 2n monitors the cats.

 

i have also read about spark plug anti-foulers.

 

now here is the real question i am asking

 

would it eliminate the 2nd o2 sensor if i swapped in an ecu from a 91 legacy sedan? how would the 1st gen legacy ecu differ from that of a 95?(power maps, etc)

 

i have the earlier ecu left over from an attempted ea>ej swap, and since obd1 motors can be swapped in place of obd 2's , then this is why i am asking this question.

 

EDIT: might i add my car is manual transmission, no EGR. the spare ecu is a 91 fwd 4eat

 

 

In theory at least, I find this to be an interesting question. My understanding is that the O2 sensor supplies a signal voltage to the ECM.

The voltage varies with the amount of oxygen in the exhaust. So, first find the voltage output for a happy O2 sensor. You have 12VDC running all over the car, it should be easy to pick off the appropriate voltage. Feed that voltage to the O2 sensor inputs at the CPU. Your ECU should never know the difference. Since the nominal 12VDC varies a lot, you'd want to build a circuit with a voltage regulator. After the regulator, you'd want a high resistance multi-turn pot, pick off your simulated O2 sensor voltage and feed it to the ECU. I'M NOT RECOMMENDING THIS. I'M JUST SPITBALLING A VERY ROUGH IDEA. Personally, I'd just pop for the replacement O2 sensor. It will increase your MPG, and everyone likes breathing clean air.