Is a load resistor really necessary when using a wideband?

[leres]

I've seen info here and other places including the PLX application note:

http://www.plxdevices.com/AppNotes/PLXApp004.pdf
Stock Narrowband Sensor Replacement

that says you need to use a load resistor when using the narrowband output of a wideband such as the PLX M-300. This doesn't seem necessary to me (with an F-Body at least).

I looked at the wiring diagram in the service manual and it looks like the PCM does not control the heater circuits (they're hot any time the ignition is on) and thus it has no way to monitor current being used by the heaters. (An example of a circuit that the PCM does monitor is the skip shift solenoid, see DTC P0803).

I also looked at the descriptions in the service manual for the DTCs having to do with HO2S heater performance (DT0135, DT0141, DT0155 and DT0161). Heater tests are run once per ignition cycle and only on a cold start. Essentially, if the sensor start producing output within a certain amount of time (which depends on coolant temperature and air flow) the PCM assumes the heater is working.

One last question; what's the best way to obtain a spare female metri-pack series 150 4-way connector? I believe a male connector pig tail (PCM side) is available from the dealer (Delphi 1216-0825) but I guess there's no good reason for them to stock the female version (O2 side). I've done some research and I believe a Delphi 1216-0482 is the correct part but I can't find an online vendor who stocks them. Am I stuck either hacking the harness on one of my existing O2 sensors or going to the wrecking yard and scavenging one?

[dfe1]

Your best bet may be to order an extension harness. That way you'll get male and female connectors already crimped to the wires. I know Random Technology sells these and I'm sure other companies do too. Not sure if you're aware of it, but you'll need a Metripack crimping tool if you want to make up our own cable/harness. The good ones cost about $150.

[leres]

Thanks! It looks like Caspers Electronics makes "square" O2 extension cables (various lengths are all the same price) and a lot of online vendors carry them. The cheapest option is their "A/F pigtail" which is just long enough to tap in a give an output for an A/F gauge.

Specialty crimping tools are nice and I'm not opposed to forking out for one but I've also had good success closing pins with plyers and then soldering them.