Ford Econoline 1983, 4.9 6L in line engine hissing sound from manifold
 

Hey guys!
I have this hissing sound coming from a something on the exhaust manifold. I have attached pictures of it to give you a better idea.

My question is what is it (some kind of sensor???), is it fixable/replaceable and how serious issue this is. :-huh
I am about to leave for 3000 km road trip next week.

I am very grateful for any advice or directions as I have no clue what the thing is.

Thank & have a good one!
Lukas

*UPDATE & more pics*
 

I popped the engine cover to see better what is going on there and found out that there is a line going from the top of "it" into a carburetor.

Any ideas? I can't find anything online or in the Haynes manual...:(

I went to a Ford dealer and got answers...
 

So, just in case that somebody would have the same question in the future...here is the answer.
The part is not available new anymore...they said just go ahead and plug it. The other end is supposed to end somewhere in the air box and they are not sure where exactly. I don't think that on my truck there was anything plugged in there before. And there is nothing hanging loose around....

Man.......have not seen that engine in a long time, and don't miss it either.

What you (were) looking for is what they use to call the "Choke stove pipe"

It took heat from the exhaust and feed it into that back cylindrical device that has a spring in it, the warmer it got, the more it open the choke, to max.

I see you kind of found your own solution to this, with your own research. :-X22

You should be fine running it with the exhaust port plugged, as long as your in a warmer climate, and don't really need the auto choke for cold starts.

What you might what to do is turn the auto choke (that back cylinder) back to lean, so that on cooler mornings, the choke does not close, and stay closed until enough engine heat will open it on it's own.

There use to be a "kit" you could buy, that replaced the spring (auto) and had a cable running to the dash for "manual" choking on cold starts, and you needed to remember after some time to push the knob/cable in to get the choke fully open to keep it from running too rich/sucking gas.

And......they still have them - http://m.autozone.com/fuel-delivery/...n-kit/1043_0_0

I for one, am really glad they started using fuel injection and throttle body's with electronic ignition after '86 :) Solved a lot of these old problems.

Hi Wildman and thanks for your reply! ;)

When you say "turn the auto choke (that back cylinder) back to lean" how do I do that exactly? Right now the "lean" mark on the cylinder is placed horizontal. You can see it on one of the pictures but the picture loaded to the post sideways.
Also I remember I had to, after every start (hot or cold), step on the accelerator pedal to drop the idle speed (choke?) down. Often I had to wiggle a little lever in the back of the carburetor to bring the idle down. Now I don't have to do that anymore (pedal or manual) so maybe the choke got stuck??? I don't drive the van during the winter so it might be possible...?

Would you know by any chance where the missing line on my van should be originally plugged? At Ford they said somewhere in the air box but they were not sure and I don't think there is anything free available on my air box. The only thing I can see hanging loose around there is the red little hose on the right side of the carburetor (it is visible on the pic also). Could that be it? According to the diagram I got from Ford it could be around there...
I might want to plug things the right way after the trip as I just like to do and keep things right on the van. :p

Thanks in advance for your time!
Lukas

And yes, right now the engine starts a bit worse then it used to when cold and needs to warm up to drive and run smoothly....

And that shows that your missing a choke for the cold starts.

Not to get into a long explanation about this.......plus 25-30 years since I've dealt with this issue.......Simply, there is a bimetallic spring inside that black plastic cylinder, the choke stove pipe sends "heat" to the spring, which expands and opens the the choke fully, when you start from a cold start, you hit the gas pedal about 1/2 way, that closes the choke (totally unlike a fuel injected system) and as the engine warms up, the spring will open the choke and you drive as normal. That allows the engine to run rich until operating temperature is reach (again, totally unlike a fuel injected engine) Pure Ole school tech.

That tube your looking at in the pictures, the one with the insulation wrap on it, is the choke stove pipe (or tube) oh, and by the way, that insulation is an asbestos material.........:-roll If you follow that tube, it's connected to the heat spring, and should be connected to the open port you have in the exhaust manifold.

Like I posted above, it might be better to order that re-fort kit, and convert the choke to a manual choke, like it the really old days, like in the 50's, 60's before the "automatic" chokes were added. :-X04