running rich?

[vanagonforever]

I recently replaced my entire exhaust system on my 1983.5 1.9L WBX. Since I did that the van hasn't sounded as smooth at idle as I remember it sounding a few months ago. When I replaced the exhaust I also replaced the O2 sensor. I bought a new Bosch universal sensor from AutoZone and attached it to my existing sensor wire.

Now here is what I see. I see drops of a clearish liquid dripping out of my tail pipe. I assume this is unburned fuel because it smells like it. The engine is also surging a bit during idle and in general doesn't sound "comfortable" at idle. When I drive everything sounds ok but I do not see the black smoke comming out of the tail pipe that I thought would happen if I was running rich.

My thought it that the sensor I bought is either bad or doesn't have a good enough connection. When I disconnect the O2 sensor completely I don't even notice a change in how the engine runs. I bought a multimeter so I could check it but I just wanted to see if you guys had any other ideas about things I should be doing to try to fix my rough idle. Did I need to get the Vanagon specific O2 sensor?

Thanks!
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1986 2WD 2.1L WBX Vanagon Weekender
1983.5 1.9L WBX Vanagon Westfalia

[tencentlife]

Any clear liquid that makes its way to the tailpipe would have to be water. Gasoline wouldn't condense at the temp of the muffler or tailpipe. The water will be stinky but I really doubt it's gasoline dripping out.

Water condensate is common to see as the engine warms up. But water can also foul an o2 sensor. When they foul, their signal V goes low, and the ECU sees that as too lean and it runs rich. The basic tune without o2 signal on these is intended to be a little rich anyway, so without o2 signal, the result is the same.

All narrow-band o2 sensors do the same thing, the differences being whether there is a built-in heater, and whether the sensor body gets a dedicated ground wire instead of grounding thru the exhaust hardware. 1.9's had no heater power supply, and didn't use the dedicated ground version, so any one-wire sensor should work. But bad sensors in the box abound.

If you get the engine fully warmed up it should burn off any condensate in the exhaust, and the sensor should heat up and dry out. Bear in mind you also won't get normal lambda operation until at least ten minutes of running from cold, and it could be even longer before it normalises with an unheated sensor.

If I lacked any way to monitor mixture I would probably warm it up thoroughly, then adjust CO by ear for smoothest idle. Then drive around awhile to dry things out. Then I would test the sensor V with it disconnected, and connected to see that the lambda control is responding.

Don't be tempted to remove the sensor and clean it, unless only with clean compressed air. Any kind of solvent spray, WD40 or anything you might be tempted to use will ruin the sensor immediately. Also, if you used any silicone sealants in your exhaust install they will kill a sensor.
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https://intrepidoverland.com/vanistan/

Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

[floggingmolly]

BN and TC,

On the topic of 02 sensors, I searched the local FLAPS website and see a huge difference in price. There is a Bosch one for $160 (upstream sensor) and then the Bosch universal for like $25 (downstream sensor). There must be a difference right? I don't want to cheapie, but I could change out the cheapie like 6 times before hitting the price of the higher cost one.

Any thoughts?
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'85 Wolfsburg Weekender

[tencentlife]

There's two basic types in common use, wideband and narrowband.

Wideband is on late model cars and requires a very special control circuit to regulate the sensor's heater, so it gives a 0-5V signal that is linear to mixture. They have 5 wires or more. They will not work on any FI that isn't specifically built to control the sensor and incorporate that signal

Narrowband is what older cars and still some new ones use. It operates by itself and produces a 0-1V signal that is very non-linear. It's more like a switch that tells whether mixture is too rich or too lean from stoich, but gives no relative useful indication as to how much. They have from one to four wires, depending on whether the sensor incorporates an internal heater (two extra wires), plus some have the fourth wire as a dedicated ground.

Digijet and CA AFC's used the one-wire narrowband. Digifant has a heater power supply so it uses the 3-wire. You could easily add a heater power supply to one of the earlier FI's to heat the sensor and get it to respond more quickly from a cold-start. The heater isn't necessary, and there's no heater feedback to the ECU, so heater or not the sensor will produce its signal regardless, but the heated one will do so earlier.

So, what's the difference between a $25 Bosch and a $160 Bosch? Take a look at the number of wires first. If it has 5 or more, it's a wideband and the guy looked up the wrong part. The heated Bosch narrowbands shouldn't cost that much. And the only functional difference between a one-wire $25 Bosch and the more expensive heated Bosch is the heater. Both produce the same signal in the same fashion.

All the sensors, of both types, have a M18x1.5 metric thread.
_________________
Shop for unique Vanagon accessories at the Vanistan shop:
https://intrepidoverland.com/vanistan/

Please don't PM here, I will not reply.

Experience is kryptonite to doctrine.

[funagon]

The Bosch OEM 3-wire oxy sensor for the vanagon is Bosch part number 13957. Costs about $135.

Bosch part number 13913, also available at your FLAPS, is exactly the same sensor with three wires, costs about $40, and has a different connector on the end of the wires. If you're willing to splice your old OXS wire connectors onto the new OXS you can save lots of money.

Both of these sensors easily die an early death and make your van run like crap, so I only buy the cheap ones.
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1990 GL 7-passenger
2.2 liter WBX

[vanagonforever]

Thanks tencent! I really appreciate all the useful information.
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1986 2WD 2.1L WBX Vanagon Weekender
1983.5 1.9L WBX Vanagon Westfalia