o2 sensor 1 wire to 3

[88k5blazin]

I'm looking to go from the stock 1 wire o2 sensor to 3 wire. can I just cut the pigtail off the three wire and use a butt splice connector to attach the stock pigtail and extend the other two wires to ground and ignition power? or will this mess with the readings that are sent to the ecm?

 

[dyeager535]

As long the connection is good (I would suggest dielectric grease before crimping) and you shrink tube it afterwards, should not be an issue.

My preference, if going with the AFS-74, is to terminate the vehicle-side connector with a weatherpack so it mates up to the sensor itself. It's cleaner, it's positive, and it's waterproof.

I've not seen any problems with making connections in the O2 sensor wire, but IIRC, it is a different type of wire than just plain copper.

 

[eagle mark]

Some newer vehicles use stainless wire which does not solder well at all. But the older vehicles are all just plain copper wire and you can splice without issue.

I'd still prefer solder and shrink wrap a pigtail in so the O2 can be removed and serviced.

Although not needed... when I do a heated O2 sensor swap I use a relay.

 

[88k5blazin]

Some newer vehicles use stainless wire which does not solder well at all. But the older vehicles are all just plain copper wire and you can splice without issue.

I'd still prefer solder and shrink wrap a pigtail in so the O2 can be removed and serviced.

Although not needed... when I do a heated O2 sensor swap I use a relay.

That was my next question. What's the point of putting the relay in between?

 

[jekquistk5]

That was my next question. What's the point of putting the relay in between?

It's not needed but can make for an cleaner install. I ran mine just off of one of the extra switched ignition outlets on the fuse panel.

 

[eagle mark]

If you have an extra Key On space in fuse panel? That works fine. I usually use a relay because there is not a spot for it and I don't want to increase the load on a circuit. Like if you add it to a fuel injector fuse and it blows? What caused it? Fuel injector? Heated O2? Is it just overloaded? Short?

 

[dyeager535]

This is where adding an auxiliary fuse panel starts to make sense...

Not always necessary, don't get me wrong, but if you intend to start adding other electrical components that need switched on/off, relays, etc., it's easier to just wire in one of those panels and add as you see fit from there, instead of using the fuse panel until it's a jumble of piggybacked connectors running off of one circuit breaker, THEN deciding to swap over to something closer to the battery.

That's what I did, the later panels have so many slots it saves a lot of work. Run one wire from the fuse panel to the aux. panel to run a relay for switched ignition sources, other wire direct from battery, pretty much done.

 

[cuervo]

When I switched to a heat O2 sensor I read some where that you should keep the length of the line as close to stock as possible.

On my 91 I crimped and solder the connection on the new connector.

 

[88k5blazin]

This is where adding an auxiliary fuse panel starts to sense.

I picked up this relay/fuse box out of an old mini van if I remember correctly. I'll try an get a picture up later today. It has a bunch or relays and fuses with connectors on the bottom and a main feed that I'm assuming would go to the battery. Is this what your speaking of? I originally got it because I planned on adding some lights and electric wind star fans.

I think I'll start by just running the one relay for now because I want to get her running right first but after that I got a laundry list of projects I want to start.

 

[eagle mark]

That should do the trick. I find all sorts of GM relays, inline fuses, power distribution blocks, fusible links etc... while junk yard shopping.

 

[88k5blazin]

I was hoping to install this somewhere in the engine bay and start getting all my accessory wires fed into it. Not 100% sure if it will work but I think I only paid 10 bucks for it

 

[dyeager535]

Looks about like what I was thinking of too...should work fine for whatever you need to do! Hardest part seems to be finding the best spot to make it a clean install.

 

[eagle mark]

Wow that's a lot of extra power! I'm usually looking for something half that size.

 

[88k5blazin]

Yea it's definitely overkill. I don't make it to junk yards often so I just grabbed it.

When you have a bunch of relays in a row can you link the grd and key ign in a chain to the same sources?

 

[dyeager535]

It depends how they are wired...you have to look at the underside.

Depending on what you are running, what I've done is use a 30A relay to turn "on" a block of fuses, and run everything off of that. Obviously low draw stuff (heated O2, ECM ignition power, injectors, etc.)

Since it takes very little curent to "switch" a relay, you could probably use one ignition wire from the existing fuse panel to turn multiple circuits on via relay if you wanted to.

If you need to turn multiple things on, you could either use a single relay to power multiple low-draw fused circuits, or use a relay to turn on more relays, or a single wire to switch multiple relays on at the same time. I guess whatever is easiest for you.

The headlight relay mod for instance, would be perfectly suited to that panel you have. Use the existing headlight wires to switch a couple of relays, wire from relays to headlights, done!