1973 VSV advice

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Feb 27, 2013
Oakesdale WA
I'm working on getting my stock, one owner (I'm the second) 1973 FJ40 back on the road after its 20+ year hibernation and I have a question about the emissions system. I know a 73 is a "transition" year so its a little odd, but what is the recommendation for the emissions equipment? I'm not in an area that requires any sort of emission testing so what is the best thing to do about the VSV? If its not going to harm anything or hurt performance I would like to just cap off all the ports and leave it mounted to the fender, however I've seen some threads where people say their FJ40 ran so much better when they fixed their VSV/emissions equipment so I'm wondering if I should go that route? As far as I can tell I still have everything that was originally installed on the vehicle from the factory including the belt-driven vacuum (?) pump so I can go through the process of revitalizing the emissions system, but if its not going to improve the drivability of the vehicle I'd rather not mess with it. I've confirmed that I have the original vacuum retard distributor (upgrading in the near future) that I know I want to have capped off from the vacuum system regardless.

I'm not going for a 100 point restoration....I just want a reliable rig to drive around on nice days. I'll definitely hang on to all the parts I have, but if I can just cap off all the ports and call it a day that would be awesome. If the consensus is to fix the emissions system does anyone have into on the 1973 specific setup?

Thanks and happy early Thanksgiving.
I think you answered your own question.The only people who seem to keep the emissions are those living in a smog state(mainly CA owners) and the nut and bolt concours restoration folks.

No harm in removing properly, cleans the engine bay up alot.Definetly save the parts as you mention.
There is a definitive desmog thread here with details, just use search. Jim C sells a pulley to replace the air pump pulley.

Enjoy your turkey day!
Thanks for the info @sterling. I was searching "emissions" and "VSV"......I didn't try "desmog". I'm still not able to find a thread that specifically describes the 1973 model. From what I can find it seems like 73 and earlier really aren't affected too much by the emissions system, so it shouldn't be detrimental if I eliminate most of it. My thought is to just remove the 4 small vacuum lines from the VSV and plug the ports with little rubber caps. I'll all cap the 2 ports on the intake manifold as well as the vacuum port on the distributor. I think I'll leave the VSV box in place as well as the canister on the passenger side fender if that's not a problem. Does that sound like a decent plan?

If anyone can link a thread that goes in depth on this model year I'd greatly appreciate it.
@dmaddox Thanks for the link to that emissions manual. I didn't realize there was a book dedicated to the emissions system itself. I understand the desire to keep the truck stock, and I'm doing that an extent that is practical. I purchased this FJ40 from the original owner and he kept everything with it.....luckily. If I take ANYTHING off the vehicle it gets bagged and tagged. My thoughts regarding the emission system is that if its not really necessary on a 1973 model then I can cap/remove it and not have to deal with the expense of getting it working correctly. On the later models it seems like the emission systems are far more complex and probably have a larger effect on performance, so if I was dealing with one of those years I would likely be investing the time and money to get the system back to working correctly.

I'm still searching for information specifically regarding the 1973 system but I'm definitely learning a lot about the emission system in general as I go.
The smog pump could be a liability, as it makes your exhaust hotter, and could damage the manifold or the intake manifold. Cracks under carb on 2F are common.

Everyone has to make the fuel tank vent somehow. I don't agree with hacks (running fuel vapor straight to air cleaner would be quite interesting with backfire), but, I can't imagine running the antique VSV, particularly with the sophistication of later years.
@adavis like you I also have an original owner Aug'73 (I am the 2nd owner). It was parked since '06 until my purchase and it is finally back on the road now. Story is posted here on mud.
It had all been desmogged back when replacing carbs (has a Holley) and installing headers was common, the PO did hand me a rusted pump assembly and some other pieces. Have attached here pics of how the capped off bits look and also relevant pages from the 1973 Emission Control Manual that came with it. Let me know if I can take any additional pictures for you or you are welcome to come down since you are in WA and take a look. Drives great and no issues. No DEQ for '73 in OR so no problems with emissions.....Ozzy
TECS 14.jpg
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TECS 18.jpg

TECS 16.jpg
I've seen where folks get charcoal from the aquarium section of the pet store and replace the antique charcoal with something a bit more activated. Something was wrong with my vapor system and when it got hot in the cab, it sounded like a trombone or alphorn from underneath the body, I need to install the new OEM check valve after the fuel/vapor separator, and make the muddauber nest history from the air intake on the charcoal canister. As far as I can tell, the little barb for the 2F manifold that connected to the VSV was a flame-arrestor. Other brands/builds use a vacuum signal to open a purge valve on top of the charcoal canister, which is intended to go somewhere in the intake; could be helpful, as it is still sold as new equipment (aftermaket).

My Haynes suggests that '72 and '73 start with computer control of the VSV for purging the fuel tank. There are pictures of rebuilds for the computer, here in tech. It is probably really common, as their is a voltage spike that happens when someone tries to jump-start it; later manuals say to load both autos with amperage (headlights etc.) before you disconnect the cables, iirc. I'd never try to jump-start anything with EFI, that isn't a beater, if I didn't have to.
@OregonOzzy THANK YOU THANK YOU!! That is exactly what I was hoping to get! The pictures are a bonus too. I really appreciate the info. You still run the vacuum line from the intake to the VSV....is that to allow the VSV to operate the charcoal canister? I can easily retain that same vacuum line, and I wasn't planning on removing the larger line that goes from the VSV over to the charcoal canister. I can't tell for sure from the picture, but it looks like the 4 small line on the VSV is capped off too? I notice that your PCV port is blocked off (at the base of the carb) but I think I'll keep mine.

Thanks a TON for that info. I really REALLY appreciate it and will hit you up if I have more specific questions.

@Grayscale So you're saying it is possible to open up the charcoal canister? I haven't even touched it, but I assumed it was a sealed unit. If it is possible to open it and refill with fresh charcoal I will definitely do that. I'm hoping that if I have the VSV connected to the intake vacuum it will still operate the charcoal canister portion of the system, as it sounds like that helps with venting and fuel vapors from the fuel tank. Is there a way to tell if my VSV is still operating correctly? I'll search for the rebuild pictures and research that process as well.

@FJ40Savvy Thanks for the links to all the manuals. I have a few of them in hard copy, but its super nice to have them linked here as well.....
@adavis first a disclaimer, I did not perform this de-smog, the PO did a long time ago and it has been working fine. I just replaced the associated hoses and made sure the plugs/cappings were still doing their job. To answer your questions;
3 of the 4 small dia outlets from the VSV are plugged.
The single non-plugged line goes to the intake manifold, with the top of that assembly plugged. (3rd pic).
The large dia hose from the VSV is connected to one of the 2 ports on the top of the charcoal cannister, (2nd pic).
Bottom port of the charcoal canister is plugged.

It has a Holley carb on it with a Downey adapter plate (3rd pic) . The plugged port at the base of the carb you see is not being used for PCV connection. There is another port.
At the base of the Holley carb is another port (facing the back of the engine) and that is still connected to the PCV valve (sorry no pic of it right now).
Hope that clarifies the set up.
Regarding the charcoal rebuild, I saw it on the web, so confirmation bias if you are inclined to play with RTV vs something factory, in my essentially uninformed opinion. It was done on a later Cruiser, the kind that gives you codes if the evap is wrong. Some of the stuff that they make for GM will probably fit in a Cruiser, and it will probably plumb up correct as well is my guess. I park outside, so I have no garage to stink up, still working on other stuff.

However, why not try whatever is under the hood and see if it works? Probably needs just good paint for most of us.

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