Category: Maintenance Log

Wide band oxygen sensors and controllers are a difficult bunch of products to figure out.  Some sources I’ve read claim that I don’t need one and shouldn’t spend the money on it.  Other sources say it’s absolutely necessary if I am to achieve a decent tune.  Also a wide band O2 sensor can lead to closed-loop control which helps improve economy for cruising.

Strangely, the MegaSquirt products only support narrow band O2 sensors natively.  Otherwise, you have to have a separate controller for the wide band sensors to work with the MegaSquirts.  There used to be a DIY board available but it seems to have fallen by the wayside.  Now the main two options that are available seem to be the Innovate LC-1 and 14Point7.  The 14Point7 would end up costing less although there seems to be more readily available support for the Innovate LC-1.  Also the LC-1 is a smaller package that would more easily be installed and appears to be weatherproof.  On the high end, I will be out $209.  On the low end, about $150.  Is the extra 50 or so bucks worth the DIY AutoTune support?  Also there are a lot of people using the LC-1 successfully…

The temperature sensors I need for my project are readily available through NAPA and elsewhere.  It’s cheaper to get them there than on EBay or elsewhere.  The GM Part number is 15326386.  They are $11.99 each if I want to wait for them to be shipped in or $12.99 to pick them up today.  I will need two.  One will be a coolant temp sensor and the other an ambient air temp sensor.  I can get the connectors for these sensors with GM part number 12162193 and 12103881 (first is connector, second is terminal).  On EBay the connectors are about $2.50 each and the terminals are $5 for a pack of 25.

Poking around in the service manual for my PC800, I found a section talking about the ignition system.  The ignition pulse generators (page 16-2, item #4) and associated wheel are just what I need to measure in order to time injection events.  I hope that I can read them with a MegaSquirt without interfering with the stock ignition system.  Perhaps after I get the bike well-tuned, I will dabble in ignition control.

The front pulse generator runs on the white/blue and blue wires while the rear pulse generator runs on the white/yellow and yellow wires.

Page 16-8 in my manual gives a good schematic view of the pulse generators and their location.

I believe these are also called crank position sensors.  They are most likely inductive in nature, giving a voltage spike with every passing tooth.  The PC seems to have seven teeth with one area in between teeth having less metal than the other areas.  This most likely will lead to a lower voltage in that area.  That will show me where top dead center (most likely) is for the engine.

It looks like the NT700 uses the same technology, although much more advanced, to generate timing data.