79 FJ40 - Removing Emissions System (1 Viewer)

[CUSailor]

This is for a 7/79' FJ40

There is a full network of vacuum hoses, most of which aren't connected to anything, the rest of which seem to connect to various parts of the defunct emissions system. I don't believe that the emissions system is functioning, the smog pump has no hoses coming to or from and never has since I've owned it. The charcoal canister looks like it's seen better days etc.

I do not live in a state that requires inspections so I would like to just pull all of that equipment out to clean things up (I guess not the environment).

Can I do that? Is there any reason I shouldn't be able to remove the smog pump/charcoal canister and all tubes and piping that are connected to those? I know that I would need to get an Air Pump Delete Idler pully to support the belt, though I see that TLC has those in stock. Surely it can't all be this easy....can it?

 

[MoCoNative]

I'm not a smog nazi, but I can say from personal experience many of the emissions systems are good and help to make a 40 a little more enjoyable.

The charcoal canister is one system you need to retain in some form. It is not a complicated system and there are plenty of diagrams on this website to see how it is hooked up and works. It is actually the vent for the fuel tank. Without it you will need to change the gas cap or rig it to allow air into the tank as fuel is used. Along those lines, on sidehills and such the tank will leak out the filler without the sealed cap and hot days will make the truck fumy. I can't recall off the top of my head what activates the purge function on a 79. On my 73 with the electronic solenoids gone and no computer I'm using a simple vacuum actuated purge valve to dump the canister into the carb, works pretty good.

Fuel return line is good to reduce dieseling problems with hot fuel, so is the carb fan, almost a necessity on the later 2F's to guarantee good starting when hot.

Air pump and injection is not always needed. You will get some backfires within the exhaust when letting off of heavy throttle without it. The idler will replace it, but you also need to cap off the whole system and get the proper plugs for the head.

Some of the bimetal valves located in the thermostat housing control how and when the air pump does its thing, others control when vacuum is used on the distributor and when charcoal canister fumes can be injected into the engine. The other vacuum lines to the distributor are needed, as is the High Altitude Compensation valve if 79 had that ???? and its associated lines to the carb and distributor. Well at least they are needed without alot of extra tuning to take their place.

I suggest you look up some desmog threads and see just what you have left and what systems are intact enough to retain. Just stripping it all may be problematic. Some of it can come off though, no doubt, especially if it is not hooked up.

 

[CUSailor]

Thank you for the thorough advice! I just saw some loose hoses and noted that nothing was connected to my smog pump and figured that it was all working ok without it anyway. I'll see what I can do about re-running lines then. Certainly had no idea that it was used as a vent for the fuel tank.

I'll look up the fuel return line, I have an aftermarket Carb, I think it's Weber but I'll need to look. It was replaced about 10 years ago before I did any work on it myself. That being said, I don't think there are any vacuum hoses coming off my carb as it is now.

Looking through diagrams, I can tell that there is no rail for Air Injection, along with a few other components. I also have always had a green vacuum valve disconnected and dangling, looking at diagrams I suspect it is the VTV Valve. I've attached a photo from the drivers side to show smog pump/head and a photo on the passenger side with the unhooked valve circled. If you notice anything or have any insight to what is critical to be fixed/replaced let me know please! I'm going to pull the wiring harness in the next week or two and start working on that as well, see my other thread if you have any insight on ignitor module replacement please!

 

[MoCoNative]

Wow, that is messy.

Having a weber clears up some stuff. I'm surprised you have an externally regulated alternator, I thought by 79 they were internally regulated. On your coil question, I would just watch the classifieds for a good used ignitor/coil from somebody. You have a good distributor, those are electronic, the whole ignition system in stock form is excellent and dead reliable. I have a 60 series with 250,000 miles and it has never faltered, I wouldn't mess with it.

Your charcoal system, or EVAP system as Toyota would call it is pretty intact. One line goes to the vapor separator, which is a plastic deal behind the metal cover behind the seat that covers the fuel tank filler. As long as that is all intact and hooked up, leave it. Toyota designed it so that the fuel tank can vent in any orientation. The separator drops out gas and lets the vapors come forward to the charcoal canister. There is another line out the bottom of the canister, that is the actual breather. The next line leaving the canister travels up and over the top of the firewall. This would have gone to an electric vacuum switching valve on the fender. That valve would have been controlled by the emmisions computer, typically bolted to the firewall behind the clutch pedal inside. I don't know if that is present on your truck, any of it, can't tell, looks like the plug is empty below the brake master. Vapor from the can is burned in the engine. The computer controlled when this would happen based on engine temp and sometimes speed of the vehicle. The idea was to only introduce the extra vapor when the engine was warm and cruising so that the idle mixture and such would not be affected. The other thing on the charcoal canister would have hooked up to the third nipple of the canister if it is present. This item looks to be blocked off with a bolt. This vacuum valve and its line ran to the float bowl of the original carb. Its purpose was to capture vapors from the float bowl and direct them to the canister while the vehicle was off, helped with boiling of the float bowl and smell of gas. When running that valve is closed electrically as vapors are burned in the engine at that time. Your Weber does not hae provisions for this. (I would be interested in the valve and lines actually.)

An easy fix, is leave most of it. You can remove the float vent stuff and cap it. The vapors can be burned with a simple valve, (DEMCV10039) that GM used for the same purpose. The two large ports go from the can to the PCV vent line, the small port can be teed into the vacuum advance line for the distributor. That should be ported vacuum and will only let vapors be pulled from the can whenever the throttle is opened beyond idle. I'm running this settup and it has been working great.

Other items. That distributor has two vacuum advance pods. One is the primary advance and will do 10 degrees I believe. The other is the High Altitude Compensation Valve advancer. It seems your HAC valve is gone. Not needed. Just make sure the advance vacuum line from the base of the carb is going to the inside advance port. Cap the other and set static timing at 7 degrees if you are near sea level, or add up to 4 degrees as the HAC did if you are over 4000 feet elevation. Lots of guys just run 9-11 degrees advance anyways. I've played with a range, really depends on elevation and engine. The line you have circled was the original vacuum advance line for primary advance, the plastic deal is like a speed bump for vacuum and slows down pulse from the carb, so the advance moves more slowly and smoothly, doesn't let timing bounce. You can try it inline there, see what it does, not necessary though.

The other line sticking out over the distributor is a vent for the cap. Hooks to the nipple near the coil wire on the cap. Not sure if you have the other nipple that was supposed to draw air from in the cab, through the cap and into the air cleaner. It keeps the cap dry and corrosive gases from eating up the cap contacts. Right now you are letting water right in the distributor. I would at least hook up the vent hose.

They make nicer allen headed plugs for the air rail holes in the head, but yours look capped fine. Probably rusted in anyways.

Fuel return is handled with your fuel pump. There should be a filter for the fuel line near the battery tray bracket on the feed line to pump. The return just dumps back to the tank. I would removed the plastic fire trap filter near the carb. Get some 5/16 fuel line and cheap bender from the bargain box at the parts store and bend up a new hard fuel line from the pump to carb and minimize as much soft line above the manifolds as you can. Just cut off the ends so you have bare line to work with and sip the hose over with good clamps. May even be able to find fittings that will let the flare nut work on the carb end.

Why on earth is you factory power steering not hooked up, it is great, use it. Also, you mentioned re-wiring everything. That is a huge job. Unless things are really bad, just fix what you can. Don't mess with stripping out the emissions wiring, it is a waste of time, just neatly tape the un-used plugs onto the loom and call it good.

Idler can be purchased for the air pump, also if the bushings seem good in the pump, you can easily remove the back, and remove the carbon vanes from the pump itself and then it will be useless and be an idler for now, won't hurt anything.

Hope that helps you clean things up.

 

[CUSailor]

MoCo, this is great information. As for the power steering, this was after we started to pull some hoses/belts to get at other items. It runs well. I'm also really happy you identified the mystery green plug on the drivers side, I've always wondered what that connected to and now I suppose I do. Luckily I'm about at sea level so no need to worry about High Altitude performance, though I'll set the static timing as you mentioned.

If you're still interested in the line and valve that I'm not using, their yours once I get this thing put back together (expect it to be a couple of weeks).

Long story short we pulled the head to clean it up a bit and hopefully solve some issues, but that's opened another can of worms. I'll be posting a separate thread on here asking for advice on that.

Have you ever had any concern about the Smog pump bearing seizing up? Is it worth putting a 'dummy' pully of sorts in there or should I just let it ride until there's an issue?

 

[MoCoNative]

Well the tensioner pulley that a few places sell is obviously a much cleaner install. If you are short on the cash for it, gutting the pump works. I cleaned the one up on my FJ60 about 15 years ago, and put it all back together, cause it is still smogged and it has been fine. But, I think it was just in good shape anyways. What kills them is the powersteering pump leaking on them for decades and lets the insides get gritty. They are pretty much dry inside with some grease on the bearings as they rely on resin and carbon faced wipers to make air, so not grease or oil should be in them.

There are some threads on rebuilding/gutting them. I can't recall if I pressed the inside out to get to the bearing now. I did it behind my college apartment and at the kitchen table.

I would be interested in the parts you are pulling.