Long story short i broke down a couple weeks ago with symptoms of running out of gas. sputtering, lurching, loss of power... (had 3/4 of a tank) not knowing exactly what it was. I then went on to replace the fuel filter. nothing changed.. i would start it up and it would run and idle fine for about 20-30 seconds then sputter and die. I then bought a new mechanical fuel pump and started to replace it... i found a couple of small chunks of cream colored plastic on the inside of the fuel pump...
another long story short I replaced the old timing set and water pump and a couple cracked hoses and then the fuel pump and put it all back together. refilled the radiator and fired it up.. it ran great for a couple days and then started doing the previous " i would start it up and it would run and idle fine for about 20-30 seconds then sputter and die."
i did a series of tests.. sprayed carb cleaner around the carb to check for hi-rev or (vacuum leaks).. nothing
i then disconnected the soft line from my fuel pump and ran a fuel line to a gas jug and ran it like that.. ( assuming there was a clogged line or something).. no change..
i then started just messing around with stuff out of frustration and found that wiggling some wires that lead to the carb while it was idleing made it idle rough and eventually die..
i finally got the wiring to where it wouldn't "short out" and zip tied it in place.. it works great for now but i know its only temporary.. basically i think its sending wrong signals to that sensor on the back of the carb... if you guys know any wiring harnesses that i could replace it with or any bypass ideas that would be great!?
i believe its a 2150 motorcraft carb
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Most of those connections don't directly effect the carb. Probably the only one that does is the one above and to the right of the AA in the label on the valve cover. The rest are most likely either inputs to or outputs from the computer, and the computer controls the carb.

However, from what I've read and seen even if the computer can't control the carb the engine won't die. There is a very narrow range of change to the air/fuel ratio that it can accomplish, and that won't kill the engine. I think it is more likely that the computer is getting its knickers in a twist when the connection(s) break and the result is that the engine dies. There is a light on the dash that indicates the computer isn't happy. Is it on? If so, you need to run the tests to have it tell you what it is mad about, and those are outlined in the stickies at the top of the forum.

 

Do you have a vacuum line going to your distributor? It would be hooked to a round silver thing coming out of the distributor called the vacuum advance.

It's the silver thing in the picture below with the little red tip where the hose would be connected.

 

P.S. I see Gary replied and already thinks you have a computer. I wasn't sure though.

 

I think that all trucks with a feedback carb had a computer. And I think that carb is a feedback unit based on the wiring and the source of the noise he's hearing. Plus, the TAD & TAB relays on the valve covers point to that as well. But, confirming that via the check for a vacuum advance is a good idea.

 

If you do have a computer, I have some ideas, but I think I am going to wait and see what everyone else has to say. It seems I have some sort of "anti-technology" agenda when it comes to these trucks. So I will keep quiet for a little bit on this.

I make myself feel better by thinking my ideas pollute less than a badly running computer controlled truck, but I guess the high road would be fixing the computer system.

 

If the problem is an intermittent short/open in the wiring harness, as it looks like it probably is, then the low road will be the easiest and most reliable solution. But if he has emissions testing then it may not pass. Regardless, we think alike - at least on this. Scary, huh?

 

If I may jump in ..if this truck has the EEC-III ignition, it may be more involved?..if you pull the diz cap and see that funny rotor..

IIRC in my 83, which had the system you have, there a live "ign" on" wires all over the engine that has things to do as it is running...connected to that computer

 

I'm not sure how much more involved that dizzy would make an intermittent short/connection. I had assumed it had that dizzy, which goes along with the computer - I think. I'm not sure I would ever be confident the problem was solved given the number of things that can be wiggled to cause it to die. So if he doesn't have inspections my recommendation is a full DS-II conversion, inc dizzy.

 

If it has no little wires going to the distributor at all, and no vacuum advance/vacuum line, it will be the EECIII.

If it has no vacuum advance/vacuum line, but does have some little wires with a square module mounted to the dist, then it's a EECIV.

Does the above sound correct?

 

............

 

Yep. And little wires plus a vacuum advance is DS-II.

 

"I think it is more likely that the computer is getting its knickers in a twist when the connection(s) break and the result is that the engine dies. There is a light on the dash that indicates the computer isn't happy. Is it on?"

.... That makes since but the light is not on and I've never seen it come on..

 

Ok, I waited long enough. What is your preference as far as fixing this thing? Do you have vehicle inspections in your area? Like Gary said, you could put a dsII distributor in it, 4bbl intake and small 600cfm carb on it and drive on.

 

Forgive me for not knowing how to appropriately quote Gary Lewis...
Well as far as fixing it id like to go the least inexpensive route.. Only cause we have our first baby due in a couple months..
I don't have any vehicle inspections in my area..
As of right now it has been running fine with the wires tied up.. But i like to fix things the right way so I'm not settle with the wire tie fix. ... I'm used to bare bones I6's so this whole computer and smog thing gets me scratching my head and needing to post on FTE.. Could you explain what you are thinking a little more?