Mike,

Unless I just got lucky I don't think it matters. I cut all three at once and just matched colors after that.

Rodney

 

Bosch specifically states that the connection should be "crimped, clamped, or secured by screws" and that it "must not be soldered".

http://www.bosch-motorsport.com/pdf/...bda/LSM_11.pdf

The data sheet for every oxygen sensor from them that I've seen has said the same thing.

 

Larry,

Thanks for the information, I haven't installed it yet, so I will go ahead and do the crimping and heat.

 

Interesting. I used crimp connectors and a pile of heat shrink (the second time!!!)

Be extra careful with the routing. With me 87 the sensor wires cooked and ended up shorting to the exhaust and left me stranded - the 12V for the sensor also supplies the fuel pump.

 

Thanks for that link, Larry. I didn't realize the sensor had the be able to breather refrence air through the cable outlet as well. I have a bad habit of going around the car and sealing things that look like they should be protected.

 

Bill,

That sheet also says it should be mounted vertically with the wires facing up. How do they expect that to happen. I don't have a lot of experience with these, but I've never seen one mounted vertically.

Also, the only reason I can think why they wouldn't want it soldered is in case someone solders too close to the unit where they might fry or de-solder it inside the housing? I've seen electronics components that said care must be taken when soldering, or that a heat sink must be used, but never forbidding it. That seems weird to me.

 

Ideally the heated type of sensor should be mounted vertically to reduce the chance of water condensation in the exhaust hitting a hot sensor. If the sensor is hot and a water droplet hits it, the ceramic of the sensor will crack and kill it. In a factory stock sensor location the sensor is positioned to minimize the chances of that happening. The heater of the sensor also takes a while to get it up to normal operating temperature after the engine is started. By the time that the sensor is fully heated, the exhaust should be warm enough to have gotten rid of any liquid water condensation from a cold started engine. Thermal shock from water hitting a hot sensor and silicone poisioning are supposed to be by far the two most common causes of oxygen sensor failure.

As Bill noticed, the sensor receives reference air through the cable. Soldering will block or severely restrict that reference air path and can result in slow response or possibly innaccurate reading. Crimping allows the reference air path to remain open. Soldering further down along the cable from a crimped junction is acceptable, but no soldering between a crimped junction and the sensor. Dielectric grease in the connector housing of a sensor that doesn't have any crimps between the sensor and the connector that plugs into the car's wiring harness shouldn't be used for the same reason.

 

Bosch supplies a special weather tight (pattented) solderless connector with every universal O2. Maybe that's what they are refering to and not an regular crimp connector.

I've seen that warning before too and it always creats debates. Some people think this it's a valid reason and others don't. To be honset, before ever seeing this warning, I never heard of O2 molecules traveling in a copper wire.

 

Take a piece of the stranded wire that they use for the oxygen sensors, place one end in a glass of water, blow in the other end and watch the bubbles.