My '93 failed DEQ, excessive CO and HC, any tips?

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Phatdoggx
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Joined: Tue Jul 19, 2011 1:30 am
What year is your cabby?: 1993
Do you own a Cabriolet?: Yes
Location: Portland OR

My '93 failed DEQ, excessive CO and HC, any tips?

Post by Phatdoggx »

I think my main problem is it seems to be running rich, I only got 21 mpg out of my last tank of fuel. I had rigged up my air intake with duct tape so probably had some leaks, but I have just replaced that part with the correct one. I also have changed the distributor cap and rotor, spark plugs and wires. I'm not convinced it will pass yet, the exhaust still smells strong. The O2 sensor wires have been cut by the previous owner and I don't know where they suppose to hook up to, there's two white wires and a black, does anyone know what color wires I should be looking for to reattach this? I need help on this as I can't register the car till it passes, I'm still driving on the last owners plates which expire next month. Thanks for any help on this.
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Briano1234
Whats that smell?
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Re: My '93 failed DEQ, excessive CO and HC, any tips?

Post by Briano1234 »

No o2 and the car will run excessively rich, as the car can't detect the fuel /air burn.

There is no polarity. White to white and black to black. 3 wires, if you go with a replacement you can use a 92 ford mustang sensor, you will just need to extend the wires, heat shrink and solder rule the day here.

Oh and a fresh change of engine oil will reduce the emissions too, also get a paper filter for tests is you are using the K&N filter.
Briano

Yes as matter of fact, I have the Luck o'the Irish...everything I touch turns to fertilizer of the bovine variety.
You can lead a user to a link, but you can't make him Click.... :screwy:
Phatdoggx
Posts: 11
Joined: Tue Jul 19, 2011 1:30 am
What year is your cabby?: 1993
Do you own a Cabriolet?: Yes
Location: Portland OR

Re: My '93 failed DEQ, excessive CO and HC, any tips?

Post by Phatdoggx »

I'm not sure what the O2 sensor wires go to, I can't find any other white wires in the engine compartment. Can someone tell me what part of the engine the O2 sensor wires go? If someone could post a picture of one on a car that would help. I looked for one on the cars in the wrecking yard, but all the Cabbys there are older and I can't find a picture on the net. I should go to a used car lot and look under the hood of one but then I have to deal with salesmen, hopefully I don't have to do that. Thanks again for any help on this.
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Briano1234
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Re: My '93 failed DEQ, excessive CO and HC, any tips?

Post by Briano1234 »

The o2 wires, are on a 4 pin connector that is usually attached to the drivers side rear valve cover corner nut.

The bracket looks like: It is past the gold oil pressure switch.
Image

There are 4 wires in the bracket. 1 brown 2 white and one black.
The black is the sensor wire, the 2 whites are heater element grounds, and the brown wire attaches to the
valve cover nut.
Briano

Yes as matter of fact, I have the Luck o'the Irish...everything I touch turns to fertilizer of the bovine variety.
You can lead a user to a link, but you can't make him Click.... :screwy:
Phatdoggx
Posts: 11
Joined: Tue Jul 19, 2011 1:30 am
What year is your cabby?: 1993
Do you own a Cabriolet?: Yes
Location: Portland OR

Re: My '93 failed DEQ, excessive CO and HC, any tips?

Post by Phatdoggx »

Thanks for the help and pictures, it's a big help. I think the last owner must have removed the bracket and connector. But I did find some loose wires in that area, a black, red w/white stripe, purple, and a blue. But no white wires. I was thinking about putting black to black and the white wires from the O2 to ground. Is this a bad idea?
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Briano1234
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Re: My '93 failed DEQ, excessive CO and HC, any tips?

Post by Briano1234 »

Phatdoggx wrote:Thanks for the help and pictures, it's a big help. I think the last owner must have removed the bracket and connector. But I did find some loose wires in that area, a black, red w/white stripe, purple, and a blue. But no white wires. I was thinking about putting black to black and the white wires from the O2 to ground. Is this a bad idea?
Yes, the o2 sensor has physically 3 wires 2 white and 1 black. The white wires are for the heating unit and are not a "ground" The black wire is the sense wire.

The ground for the o2 comes from the manifold itself.

If you ground the whites, you could blow your ecu.
Briano

Yes as matter of fact, I have the Luck o'the Irish...everything I touch turns to fertilizer of the bovine variety.
You can lead a user to a link, but you can't make him Click.... :screwy:
Phatdoggx
Posts: 11
Joined: Tue Jul 19, 2011 1:30 am
What year is your cabby?: 1993
Do you own a Cabriolet?: Yes
Location: Portland OR

Re: My '93 failed DEQ, excessive CO and HC, any tips?

Post by Phatdoggx »

Well I guess I dodged a bullet, I won't be doing that. Thanks again.
Phatdoggx
Posts: 11
Joined: Tue Jul 19, 2011 1:30 am
What year is your cabby?: 1993
Do you own a Cabriolet?: Yes
Location: Portland OR

Re: My '93 failed DEQ, excessive CO and HC, any tips?

Post by Phatdoggx »

Ok I have been searching the web and a couple different times I saw the wiring for the O2 sensor. It said, Black wire from sensor goes to purple, one of the white wires is power and the other is ground.

http://sethirdgen.org/HO2S.htm

This is a Camero website but I couldn't find a VW web site that talked about the harness side of the O2 sensor.

I have a red w/white stripe wire that is 12v with the key on and a purple wire, both are not connected to anything, I was thinking of trying this.
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Briano1234
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Re: My '93 failed DEQ, excessive CO and HC, any tips?

Post by Briano1234 »

ok, I could be wrong, I mean I have only replaced about 5 on my different bunnies.....

There are 3 wires out of the 02 sensor replacements,
2 white, 1 black.

It is a 4 wire connector, on the back side drivers of the valve cover that it "clips" into.
On the 93, with a mustang replacement (mustangs have 2 white and 1 black).

The black wire would go to the violet sensor.
one white wire would go to the blue heater voltage
one white wire would go to the red/white heater voltage

The violet wire is shielded, and that goes to the ground of the car or the connector.

90 colors are:
black wire for the sensor
blue for heater wire
red/white for heater wire.

Now they only show colors of the wires after they leave the o2 sensor plug going to the ECU.
the connector should be
t4/1 r/w
t4/2 blue
t4/3 gnd
t4/4 violet

Bosch replacement sensors have 3 wires one black, and 2 white, the 2 white are the heater wires, and the black is the sense wire.
Briano

Yes as matter of fact, I have the Luck o'the Irish...everything I touch turns to fertilizer of the bovine variety.
You can lead a user to a link, but you can't make him Click.... :screwy:
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gull
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Re: My '93 failed DEQ, excessive CO and HC, any tips?

Post by gull »

I suspect where you're getting confused is the heater requires both power and ground. The reason both wires are white is the heater doesn't care about polarity.
VW fan who fell to the Honda side of the force
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Phatdoggx
Posts: 11
Joined: Tue Jul 19, 2011 1:30 am
What year is your cabby?: 1993
Do you own a Cabriolet?: Yes
Location: Portland OR

Re: My '93 failed DEQ, excessive CO and HC, any tips?

Post by Phatdoggx »

Ya that is what I wasn't getting, I got it now though, and I passed DEQ today! I'm so relived, now I can get my title and registration done. Thanks for all the help.

Now on to the next problem. My power steering doesn't work, I'm going to pull the pump and check it out.

I wanted a project car and I definitely have that with this car!
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