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1978-1979 SMOG/Emissions


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I imagine everyone here lives in CA and has to pass smog with their 1978-1979 Broncos.. I bought my federal emissions 1978 F150 in VA and moved back to CA a couple of years ago. I managed to get it to pass smog but I know my set-up isn't perfectly right and it's been causing problems with running hot on the trail/warm on the highway. I believe I mostly have this sorted out well-enough for now (it was my EGR set-up) but was wondering if anyone in the group would be willing to share pictures/details/information about their set-up.

There are a TON of threads on this subject all over the internet, many outdated, some inaccurate, and the posts/their authors inactive. Hoping to find some current resources and confirm/gather for posterity.

Currently my EGR valve (with .24 orifice) is hooked up with the WOT valve inline, to a blue (155 degree) 2-port vacuum switch which is pulling vacuum from ported. I have the vacuum amplifier, vacuum reservoir, and a vacuum delay valve that I spent some time trying to get working correctly to no avail. Still have some trial and error to do when I have more time but was hoping to take a peek at someone else's set-up. Thanks.
Do you have a copy of the vacuum schematic that the Smog Check folks are using? Doesn't matter if it doesn't work right plumbed that way, if it is not plumbed that way when they check it over then it is a fail. If it is plumbed that way and it still doesn't work right then there may be an option.

Back when MISF was a Ref there was such a thing as a "Limited Parts Exemption." What it means is that if everything is there, and connected correctly, but a part is defective with no possible replacements available, and it is causing the system to not function properly then you can get an exemption to the Smog Check and be able to register the vehicle. As I recall you would need to do this every year, not every other year.

Not really what you were asking for, but HTH.....
I believe I do have a copy of the schematic referenced by the calibration code on my valve covers and I do indeed have all of the parts. I know for a fact I had it all set up incorrectly when it passed his visual check and the sniffer (very good readings he pointed out). I was missing the heat tube from the exhaust manifold to the air cleaner and had to come back for that (I had headers and he told me to just attach it to the headers with bailing wire, I welded a little retainer to the headers to keep it in place).

Good to know about the Limited Parts Exemption.

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