The part in question is on the manifold. It has six sides and a place to attach a hose, I think. If it is supposed to have a hose attached, where does the hose go? The FJ40 has been stuttering, coughing, hiccupping and backfiring and I am trying all options to get it running smoothly. My neighbors are getting an early alarm every morning when I go to work and when I drive through certain areas, I see people ducking thinking they are hearing gunshots when I drive by. Any help or suggestions would be appreciated.
1972 FJ40. What is this and what does it do?
- Thread starter cruiseraz
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It should be plugged or have a vacuum line attached to it. Right now, you've got a vacuum leak.
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Put your finger over it when it's running, see what happens.
Images from my factory emissions guide. If you're smogged, the manifold vacuum goes to the VSV (vacuum switching valve). If you are not smogged, it can go to the dizzy I believe. But definitely don't leave it open, or you will have a massive vacuum leak.
The carb base is ported as well. In a desmogged situation, I'm not sure there'd be much difference between the vacuum at the carb base and right off the manifold. I currently have my manifold to the dizzy and carb base port to the diaphragm. Take that with a grain of salt though, as I am certainly not an expert.
I'm looking for one of these if you want to replace it with a plug. PM me if you don't need it.
The distributor should be connected to a ported vacuum on the carb.
I tried running manifold vacuum the distributor, and the exhaust stunk... It would clear out the parking lot. A ported source will have high vacuum at idle, but it'll drop off with moderate throttle.
I tried running manifold vacuum the distributor, and the exhaust stunk... It would clear out the parking lot. A ported source will have high vacuum at idle, but it'll drop off with moderate throttle.
I was pretty sure that ported vacuum was low or even zero at idle and only came on with a crack of the throttle. The port is above the throttle plate.
Eddie is correct. The vacuum line to the dizzy should connect to the carb at a port that is ABOVE the butterfly. It should see very little if any vacuum at idle, but as the butterfly opens, it will apply vacuum to the port, and, in turn, the vacuum advance.
That's right... Had it a bit mixed up. It gives you more advance under light load and as you give it more throttle, it'll decrease.
If you've got advance at idle, it'll stink/pollute more.
If you've got advance at idle, it'll stink/pollute more.
I am curious about my vacuum advance on my 1970 Non-USA FJ40 "F" engine. Today I pulled the vacuum line off the carburetor, located slightly above the adapter plate (1 bbl to 2 bbl intake) and there isn't any sucking happening. Turned the idle adjust screw in a full turn to raise the idle, no sucking. Swallowed that hose and sucked and noted no change in the idle speed (turned back down one turn). Saw something somewhere where a fellow mentioned a "dead port" on the carburetor. What can cause this? Shouldn't I have noticed a change in the idle speed by sucking on the hose to the distributor? Thanks, Lenny.
My vehicle has a simple plug in that location. But in your photo that is clearly a vacuum leak. If you don't have a cap for it, use a piece of chewing gum. You will notice a difference as soon as you plug this leak.
I ran across this link a few minutes ago. It shows a fitting like yours and there is some information on usage.
https://forum.ih8mud.com/threads/alright-fellers-manifold-question.786359/#post-8943286
https://forum.ih8mud.com/threads/alright-fellers-manifold-question.786359/#post-8943286
