What is this?

[AaronW]

Hi, I posted this over on the build thread I started, but thought maybe I'd post it here, too.

Can you tell me what I'm looking at, here? I can't see anywhere this wire was supposed to go, and I don't know how long it's been hanging around in the engine compartment. I was trying to figure out why my ECMB fuse is blown, and found this hanging down by the exhaust on the left hand side of my engine.

Aaron

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[AuroraGirl]

Closest thing I can tell is a disconnect for timing advance used to turn off computer control but I am not sure. It’s one wire and doesn’t look like it plugs into something or maybe it just melted a lot of it

 

[AKguy]

I’d be looking at the original air filter housing base for where it plugs into.

 

[AuroraGirl]

I’d be looking at the original air filter housing base for where it plugs into.

oh is it an intake air temp sensor?
unless its the MAP sensor but its missing a few wires

 

[Camatruder]

Knock sensor ?

 

[AuroraGirl]

Knock sensor ?

I don’t think that would be in the air cleaner. Usually in the block I’m not sure about tbi. Maybe mounted somewhere more normally in reach to have comparison to determine knock vs thud on metallic part

 

[Juggernaut]

It looks like a temperature sensor wire. If so, it's really burnt up. Look at that side of the engine around the exhaust manifold and see if there's a sensor sticking out with no wire to it

 

[tobiahr]

it could be a tach wire, what color is the actual wire?

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[Dale A]

There is a one wire sensor on the passenger side of the motor above the exhaust manifold and below the valve cover lip about in the center of the block. On my engine (91 454) the sensor is for the Aux cooling fan temp switch.

 

[Raider L]

Really? All that is so weird. All that computer stuff. My daughter has a 2017 Honda Fit. One day I was going to be brainy and open her hood to look for the trans. dipstick. I couldn't find it! It was a maze of wires, hoses, this thing and that thing I didn't even recognize. I gave up and closed the hood.

 

[AuroraGirl]

There is a one wire sensor on the passenger side of the motor above the exhaust manifold and below the valve cover lip about in the center of the block. On my engine (91 454) the sensor is for the Aux cooling fan temp switch.

Is your wire white? Or does it terminate to green plastic end? I think the OPs mystery wire is white from what I can tell

 

[AuroraGirl]

Really? All that is so weird. All that computer stuff. My daughter has a 2017 Honda Fit. One day I was going to be brainy and open her hood to look for the trans. dipstick. I couldn't find it! It was a maze of wires, hoses, this thing and that thing I didn't even recognize. I gave up and closed the hood.

Probably doesn’t have a dipstick. Gm has been vanishing trans dipsticks since the late 90s and I would imagine most late models period don’t. They say the fluid is a life long fluid that will last the life of the transmission


Conveniently that’s just outside of the warranty period and in no way true, defying the idea of a fluid for a hydraulic system. In that it’s additives and properties can last a long time, yes, but contaminants, wear, and heat cycles will eventually make that fluid not so good at lubricantinf, protecting, cooling, and shifting the transmission

 

[Raider L]

What is the hose around the wire for? Heat protection? And why a hose? Why not that corrugated conduit? What color is the wire at the other end of the hose, where it comes out from? This truck is computerized, can you do a thing with the ignition key to get the computer to show a sequence of check engine blinks and decode them as to what the computer is indicating? Does the truck show a check engine symbol?

 

[78C10BigTen]

Id also be weary of that almost nonexistent plug on the alternator.

 

[Craig 85]

There is a one wire sensor on the passenger side of the motor above the exhaust manifold and below the valve cover lip about in the center of the block. On my engine (91 454) the sensor is for the Aux cooling fan temp switch.

I added the aux fan and sensor to my '85. I had to use the 91-95 style. @AaronW here's a reference photo of where it threads into the head.

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