What is this? Electrical Connection

[nickvalente]

I'm pulling the not-running 345 from my '79 Scout II and putting in a 304 from a running '74 Scout II.

What is this? It is just below the valve cover, between the #8 cyl and the fire wall.

This is on the '79 345 and not on the '74 304. I could not find it in the wiring diagrams, it is probably there in the diagrams but I could not see it.

The 304 does not have this connection/probe thing. I am guessing it is related to the air pump & emissions equipment? Neither motor has an air pump, ac and the cruise was removed by a previous owner.

I am hoping I do not need it to run the 304. The wire appears to join the harness running up to the firewall then the fuse box.

Of course, I am fixing all the bare wire situations like this one that I run into while making this engine swap.

Thanks.

 

[Eric VanBuren]

That is the temp sensor for the electric choke assistance. It prevents the choke from getting it's electrical assistance until it senses the block is above a certain temp.

 

[Michael Mayben]

That is a "another" coolant temp switch that is part of the emissions system on only the '79 and '80 345 in Scout II with an automatic transmission. It's a component of the electrically-heated divorced choke system.

The '77 and later vehicles/emissions systems and components from all manufacturers (not just ihc) began to become much more complicated and individualized depending on exactly which "option" components were installed.

These type changes and "updates" were communicated to the dealer base through the use of service letters, unfortunately, much of this information never made it's way into the actual service manuals since the light line vehicles were in their death throes at that point. If you dig deeply into the wiring diagrams in the cts 2313 service manual for '78>'80 Scout II, you will find the circuitry called out, but you won't find definitive info for functionality or testing!

Bottom line...disregard that item, your earlier rolling chassis won't have a connection point in the harness for that sensor.

So this is the donor engine we've been discussing? You are prolly gonna find a few more "mis-matches" as ya go along, but nothing other than stuff that generates questions! No big deal, we'll work around what we have to workaround! But...as ya clean things up, I'd not just cut out any "unknowns" unless it's po virus kinda shit! And since you have excellent access to the bulkhead connectors now that your original engine is out, this is the time to give that area some luv also since it's much nicer to work with standing in the bay rather that leaning over the engine!

 

[nickvalente]

Mm:

thanks for reading and replying.

I'm putting the '74 304 in the '79 chassis. The 345 pulled from the '79 is the one that will sit for now and get rebuilt... Someday.

But in any case, I'm happy not to worry about this sensor & connection.

Yes, I am trying to get a few things sorted while I can climb in there; rag joint, heater, body mounts, wiring.

Thanks again, I think I'm getting down to the home stretch, we'll see.