1979 2F HIC / hot idle control vacuum source

acy76

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Hi all--Finishing some major work on my '79 FJ40: rebuilt cylinder head, rebuilt carb, belt drive fixes, proper desmog (PO had done it about halfway and poorly).

Following the excellent 79-80 "definitive guide" here, and in this post in particular the HIC vacuum routing is described: The Definitive 79-80 Desmog Guide - https://forum.ih8mud.com/threads/the-definitive-79-80-desmog-guide.812197/post-9277965

I purchased a new carb insulator and heat shield assembly which only has one vacuum fitting on it from a vendor here: NOS OEM Toyota Genuine Parts 2F Engine Carburetor Insulator Plate HEAT SHIELD FJ40 FJ60 FJ55 1/75-1987 - VintageTEqParts.com - https://vintageteqparts.com/collections/body-1/products/nos-oem-toyota-genuine-parts-2f-carburator-insulator-plate-fj40-fj60-fj55-1-75-1984

The large fitting I have now should be the inlet for the evap system, but there is no small fitting for the HIC present. How should I go about connecting this? Should I just skip it? Truck runs well but I'd like to retain as much of the original system's functionality as I can.

Thanks for any advice.
 
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mattressking

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The port on the insulator is manifold vacuum, connect HIC to a manifold vacuum source and it will provide the correct vacuum signal for HIC. A great source is the 'gas filter' on the manifold. It's in front of the secondary butterfly on the intake manifold.
 

acy76

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Good idea. The guide I referenced has mentioned this and links an Amazon-supplied replacement, however my manifold does not have that location tapped. I do, however, have the larger filtered vacuum plug next to it, so I will plan to use that.

Of course, mine's broken--ordered a new one (3-port) from @ToyotaMatt just now. Was going to replace it anyway because the cap is loose and I think the only reason it doesn't leak (or leak more) is that it's clogged with carbon.
 

ToyotaMatt

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Good idea. The guide I referenced has mentioned this and links an Amazon-supplied replacement, however my manifold does not have that location tapped. I do, however, have the larger filtered vacuum plug next to it, so I will plan to use that.

Of course, mine's broken--ordered a new one (3-port) from @ToyotaMatt just now. Was going to replace it anyway because the cap is loose and I think the only reason it doesn't leak (or leak more) is that it's clogged with carbon.



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