Hey guys, I hope I'm not invading too much, but this place is a fountain of knowledge about TBI systems, and I'm out of ideas on my own.

I bought a TBI system from a guy on Ebay, and I'm installing it in my 350 engine that is actually in my boat. The system is from a 1993 Chevy 1500 5.7liter engine. The loom that came with the system was pretty beat up, because he had canibalized it, for what he needed for his carb, when he pulled it out.

Since the system is going into a boat, it's going to be an open loop system anyway, and won't have an o2 sensor, or any emmissions stuff.

What's left of the loom, is really all I need, except that the knock sensor wire is melted, and will need a new end.

Anyway, long story short, I've sorted out all of the wiring, and eliminated the unnecessary stuff, except for one remaining item, that I cannot find in ANY wiring diagrams that I've looked at.

It's a gray wire, that has a connector that looks very similar to a knock sensor connector, but this wire is gray, and the knock sensor wire is dark blue.

The other end of the wire was snipped at some point, and honestly, I can't tell if it ever went to the ECM at all...

Any ideas where this wire goes? I'm thinking maybe it was for an oil pressure gauge sending unit, but that's a wild guess. I've looked around for a secondary sending unit but they don't seem to be out there.

There HAS to be something like that though, because the oil presseure fuel shutof switch is just the two-wire switch, and doesn't have the pressure sender built into it.

Any help you guys could offer would be greatly appreciated.

Thanks!

 

Pass. side head thermo switch for Fan.

 

Awesome. Thanks!

So my next question is, since this connector isn't necessary on my boat, would it work to move it to the knock sensor, instead of buying a new knock sensor connector?

It looks VERY similar, but are they similar enough that it would work, and save me some money that way?

 

I checked mine, my knock sensor wire is yellow so it may just be that. Not sure if the vent switch is grey. The connector should work on the knock sensor.

 

Cool! Thanks. I'm going to do that then. I'll report back once I get this puppy installed. I'm waiting on a tap, to be able to tap the coolant temp sensor threads, since the thermostat housing for the boat splits out into 4 lines to cool the exhaust manifolds, which blocks the factory location of the sensor.

The heater hose connector broke off inside the manifold, and I have to tap it, in order to make it usable again, and the place I ordered the tap from is taking their sweet, sweet time...

Either way, it WILL be running by the time summertime hits, here in Utah.