So as I was taking my engine out I realised everything that I thought was at least somewhat in it's original state, wasn't, not even close! (Sorry Chris, another one of those posts) I assume the parts in the picture are emissions related... and obviously tampered with and not in use.

We have no testing in SC. Do I need all the parts even if they're not in use? What can I get rid of if anything? The port underneath the exhaust manifold is also blocked and the vapor line from the carb is cut as well as the tube running to the cat converter.

Just to clarify, the truck was running fine - I'm just looking to clean up the engine bay and hopefully make reassembly a little simpler...

 

The top part is the EGR valve, and the bottom is part of the AIR system. It is not legal to modify the emissions system. So making them ineffective or removing them is the same thing. But, the engine will run w/o them.

 

Gary is absolutely correct in saying that it is illegal to modify the emission system. Many have found themselves with hacked systems when making a purchase and then chose to retro fit the engines to be somewhat similar to what engines were a few years earlier.

The pictured EGR valve and carburetor spacer is something which was modified on my 1986 in order to keep the carburetor and throttle cable alignment intact. The protruding part on the right was cut off right where it was connected [just to the right of the 3/4" pipe plug] and a small aluminum plate was welded to seal the opening.

The rest of what is shown can be eliminated, along with the air pump which pumped air through this apparatus to the 2nd catalytic convertor. The metal pipe which goes to the convertor must be crimped or there will be an exhaust leak.

1984 - 1986 4.9L engines had what is referred to as the feedback ignition system. A computer controls all ignition timing as well as carburetor richness. If any part of the emission system is malfunctioning or has been tampered with [yours has!], then the computer will lock the ignition timing at static [10 degrees BTDC] and adjust the carburetor to its richest setting. The end result is poor performance and awful gas mileage. Sound familiar?

 

Thank you for the reply. So in theory I could get rid of the AIR components? There were still a couple of tubes attached which appeared to have a function(ie they weren't blocked). There is no AIR pump and although the pipe to the convertor is open the inlet on the convertor is blocked.

I wouldn't say the truck is powerful(not at all), but I haven't experienced terrible gas mileage. It averaged 14MPG over 3000 miles of mixed use, which included more than a tank of just idling(my wife would start it up while I was over the road). But you're saying it's definitely not functioning in it's optimum state and to get the most out of the engine it needs to be returned to it's original state or converted to pre-computer specs. And I suppose the latter would be easier?

 

What you will want to determine is if your engine has been converted to the Duraspark ignition? Look at the bottom of the distributor... does it have a vacuum line going to a canister, or is there a plug with multiple wires? Look at the carburetor... is there a solenoid as part of the body [driver's side] with two wires?

For reading pleasure, use the SEARCH feature at the top of the page and search for Duraspark conversion.

Here is an example: https://www.ford-trucks.com/forums/9...-86-i-6-a.html

And one more link of a similar vehicle: https://www.ford-trucks.com/forums/1...-9l-300-a.html

 

Since everything is stacked away at the moment I only have pictures to consult... I believe I have the plug with wires on the distributor and plenty of wires coming off the carb. Pics attached. So I assume I would have to do the conversion.

Thanks for the links, the first one seems like a thorough step by step write-up(from looking at a few pages, not read it all yet) - so it should be manageable, I'll no doubt be back with questions though...

 

The photos represent the feedback system.