O2 sensor connections

[tirwin]

First of all, Happy Father's Day to all the dads out there!

Still getting to know my p-car. PO said the O2 sensor is disconnected. I was doing a tune-up and thought I'd check out the O2 sensor to see where it's disconnected. Checked at the cat and it's plugged in. Found the connection under the fuel filter. Uh-oh. Looks like the orange plastic connector is broken. I guess that's easy enough to fix if I get a new sensor.

Where does the connection go from there? Box under the passenger seat?

[Scott R]

Originally Posted by tirwin

First of all, Happy Father's Day to all the dads out there!

Still getting to know my p-car. PO said the O2 sensor is disconnected. I was doing a tune-up and thought I'd check out the O2 sensor to see where it's disconnected. Checked at the cat and it's plugged in. Found the connection under the fuel filter. Uh-oh. Looks like the orange plastic connector is broken. I guess that's easy enough to fix if I get a new sensor.

Where does the connection go from there? Box under the passenger seat?

Correct, it goes to the lambda brain under the passenger seat. Plugging it back in may uncover another set of issues though... Plenty of threads to read on this.

[DRACO A5OG]

Well that orange colored connector was white but time, the elements and heat discolored it, be careful it will crumble in your hands. make sure the metal bullet connector is still there. Carefully re-attach. Place some heat shrink to keep it together if the orange housing is still there.

PO probably had idle issues that is why he disconnected it instead of fixing the issue/s.

Most likely there is a vacuum leak and the Air Fuel Ratio (AFR) is off. Smoker will find the leak and LM1 or LM2 will zero in the AFR to stoic 14.7:1

Leaving it disconnected will force her to run a bit rich and foul up the plugs.

[Lorenfb]

"Leaving it disconnected will force her to run a bit rich and foul up the plugs."

Not necessarily, a very common repeated bit of mis-information!

[Scott R]

Originally Posted by Lorenfb

"Leaving it disconnected will force her to run a bit rich and foul up the plugs."

Not necessarily, a very common repeated bit of mis-information!

This is true, mines running disconnected currently at a nice 0.8 ~ 0.9% CO which is well within the spec for my 80'

[tirwin]

Well that orange colored connector was white but time, the elements and heat discolored it, be careful it will crumble in your hands. make sure the metal bullet connector is still there. Carefully re-attach. Place some heat shrink to keep it together if the orange housing is still there.



PO probably had idle issues that is why he disconnected it instead of fixing the issue/s.



Most likely there is a vacuum leak and the Air Fuel Ratio (AFR) is off. Smoker will find the leak and LM1 or LM2 will zero in the AFR to stoic 14.7:1



Leaving it disconnected will force her to run a bit rich and foul up the plugs.

Draco,

You're spot on. I have at least 1 vac leak. I believe a bunch of things have been adjusted to compensate.

- O2 sensor disconnected
- AAV vac line disconnected
- Not sure if cat works -- might have been bored out
- Expecting that vac line to decel valve is disconnected too but haven't made it that far yet

CIS fuel pressures are verified good. Replacing original plug wires with Clewetts. Adjusting valves. Haven't pulled old plugs yet but I expect them to be fouled. Been slowed down looking for oil leak sources. Oddly enough it appears as if oil was leaking from the old oil filter and running towards the back seat and then down to the channel between the engine compartment and the upper valve cover. From there it seems to have drained down onto the oil lines. Still speculating a bit. Point is I've been slowed cleaning the oil so I can figure out if I've stopped it.

So, I am going a little crazy trying to figure out what order to fix some of these things. Figured I would get the tune-up done and then find the vac leaks. That will likely screw up idle and AFM. Reconnect O2 and AAV vac line. Then check dwell and timing. I will have to take it somewhere to get exhaust gases checked.

Frustrating to figure out all the possible variables in the equation but I'm taking my time and trying to be methodical.

[Scott R]

Start with verifying that the distributor is working, near impossible to set SC timing with frozen weights and or broken springs.

[Lorenfb]

"This is true, mines running disconnected currently at a nice 0.8 ~ 0.9% CO which is well within the spec for my 80'"

That's it. Not significantly different than it would be if the O2 sensor were connected.

[DRACO A5OG]

Originally Posted by Lorenfb

"This is true, mines running disconnected currently at a nice 0.8 ~ 0.9% CO which is well within the spec for my 80'"

That's it. Not significantly different than it would be if the O2 sensor were connected.

So, are you stating, 3.2's do not need the O2 Sensor connected like our Euro Brothers? Which would solve the irratic idle issue if all other suspects have been fixed?

[Scott R]

Originally Posted by DRACO A5OG

So, are you stating, 3.2's do not need the O2 Sensor connected like our Euro Brothers? Which would solve the irratic idle issue if all other suspects have been fixed?

OP has an 83'

[DRACO A5OG]

Originally Posted by Scott R

OP has an 83'

Understood. But I am interested in what Loren has to say about 3.2. Sorry for the Hi-Jack OP!

[Lorenfb]

"So, are you stating, 3.2's do not need the O2 Sensor connected like our Euro Brothers?"

1. With a CAT and no O2 sensor, it's likely that the AFR will not be maintained
as set w/o the O2 sensor under all driving conditions and could damage the CAT.

2. It not easy to set the AFR (CO), i.e. not just at idle, on a 3.2 as can be done on a CIS engine.

3. It you're at the track w/o a CAT, then one can adjust the AFM for the desired AFR
and 'run' w/o the O2 sensor.

Bottom line: For daily driving with a U.S. car, leave the O2 sensor connected.

[DRACO A5OG]

Thank you for the clarification Loren & OP for allowing the Hi Jack.

[tirwin]

No worries. I got what I needed to know.

So now I'm wondering if I should even worry with replacing the O2 sensor. Kinda thinking not. I'll report back on the condition of the plugs when I pull them. I'm not sure how long they've been in the car though.

BTW, figured out a little while ago that what I thought was the AAV is actually the decel valve. They just look alike... except the AAV doesn't have a vac line. Nobody corrected me either.

Headed out of town on a business trip tomorrow so it will be a few days before I get back to the car.