Heated o2 conversion wiring

[Jerrys1990]

I just got my 3 wire o2 sensor and Michigan Motorsports wire harness. Does anyone have a fuel pump relay diagram for a 1990 C1500? I'd like my new o2 to use it's own relay and fuse, but I'd like to trigger that relay with the wire on the F/P that's only hot in Start and Run. Can't find a diagram anywhere. TIA.

 

[someotherguy]

Have you checked the factory manuals? They've got the wiring diagrams. Ya know, I've never really paid a lot of attention to how the factory did it, but if you want to look - 1994 had numerous models with the heated O2. You could wire it like factory.

88-98 Service Manuals

Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...

www.gmt400.com

Richard

 

[Jerrys1990]

Have you checked the factory manuals? They've got the wiring diagrams. Ya know, I've never really paid a lot of attention to how the factory did it, but if you want to look - 1994 had numerous models with the heated O2. You could wire it like factory.

88-98 Service Manuals

Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...

www.gmt400.com

Richard

Nope....hadn't found them. Thanks for the link....I'll check it out! 1994 is still TBI, so I assume the wiring is mostly the same as my '90?

 

[thx1138v2]

You know about "assume" correct? Especially on wiring.

 

[Jerrys1990]

You know about "assume" correct? Especially on wiring.

Of course...that's why I asked I didn't find what I was looking for in the 94 manual...but in the 90 manual, The Pink/Black wire (circuit 920) looks to be the wire that powers the pump only when the engine is cranking or running. If that's correct, that's where I'll attach my o2 relay trigger wire. So, the heater should only operate when in Start or Run position if the engine is running, but NOT in Run position of the engine is zero RPM. I'm not super good at old skool schematics, so I hope I got that right....

 

[someotherguy]

While both years include TBI engines, and the wiring is *similar*, it's definitely not the same. Many 1994 models do have a heated O2 sensor from factory, so it should be trivial to locate that wiring in the 1994 diagrams. I've owned several 94's with heated O2's. Not each configuration is guaranteed to have it but a C1500 5.7 automatic is a good place to start.

Richard

 

[THEFERMANATOR]

GM powered the HO2S off the same wire that powered the egr solenoid. It doesn't draw much power(400 milliamps iirc).

 

[Scooterwrench]

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This is the factory schematic for '95. If you want to run it through a relay hook the heater to one side to the NO connections on the relay and the other side of the NO to one of the always hot lugs on your firewall block through a fuse. Hook one side of the relay pull in coil to ground and the other side to any KOEO/KOER circuit. The ignition coil feed would be a good wire to tie into for that.

 

[tayto]

I believe it's the grey wire on the fuel pump relay. this is a good way to go as the o2 heater will only have power when the engine is running

 

[Scooterwrench]

Gray wire is fuel pump. It will work with a relay but it will turn the 02 heater on for 2sec then off then back on when it gets a tach signal.