I have acquired a '79 F150 with a 428 installed in it. Recently it has developed a nasty habit of dying randomly, as though the key was turned off. It has no relation to load, speed, hot,cold ..etc, just whenever it gets the urge. To date the following has been replaced, Ignition switch, coil, voltage regulator, alternator, ignition module (which still checks good). The only thing I haven't replaced so far is the mallory distributor, and I really don't want to. I am open to any and all suggestions as to where to go next. By the way, I am 99% sure that the problem is not fuel starvation, when it does stop it will start up as soon as I go to neutral and bump the ignition. Thanks for any and all ideas on where to go next. Bob
I have had similar problems with other vehicles I have owned. I would 1. check BOTH your fuel filters, your system has 2 seperate ones. There is the very real possibillity that they are clogged. IF it were the case of the filters you should probably experience a few seconds, up to about a minute, of power loss before it just up and dies but it can just die. 2. ALso check your fuel lines, the ones running from the tank to the first filter and fuel pump, on many trucks and cars they are METAL and can corrode on the inside. If this happens and a chunk of garbage flows into a constricted point and temporarly blocks it an you will just stall. 3. Your fuel pump may be VERY OLD and could fail on you intermitantly check it out. I mention your fuel system because it seems that you have exhausted the electrical side. On another note IF u live in california your smog equipment could be malfunctioning. The equipment on older cars IS JUNK and is very prone to cause problems. Other than the electrical parts you mentioned I cannot think of anything more than the above. Hope this helps.
Hi Bob. I remember your problem on your last post, and I still have to believe it is electrical since your symptoms were identical to my 76 Bronco. My problem went away when I replaced the coil and module. Since the problem is intermitent, it may be difficult to test certain electrical parts such as your module. Did you put a new module in after you had problems, or did you just test it?
You mentioned that you have a Mallory distributor, that may be good news, and here's why. I have a Mallory on my 69 F250 410 FE. It is the Unilite series No.47 electronic. I bought it so that I would not have to mess with my points anymore. Most of the Mallorys I have seen for FE's have their own built-in module so that they can work on vehicles such as my truck that do not have factory modules. It may be possible to bypass or do away with the Ford module all together. If your Mallory is like mine, then you have three wires coming out of the main body. The red wire goes to the side of the coil; the green wire goes to Dist. side of coil; and the brown wire goes to a good ground.
You may want to talk to a knowledgable Mallory rep. or salesman before you try this. Ford made many ignition changes from 69 to 79. I would hate to have your truck catch on fire from my bad advise. If it does work, then that is just one less ugly electrical item taking up space under the hood. Good Luck!
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Be sure to double check your engine to frame ground wire and connectors. In fact, it really isn't a bad idea to have one mounted at two different locations from the block to the frame.
Hey my truck was doing the same exact thing. it would run fine and all of a sudden just start dying right? check your Choke. when ever i would get to about 30 mph the suction would pull the choke shut and cause a extremly rich condition. i just rotated my choke cap and it stopped. tell me if this helps.
I've had this on three vehicles.
1. Main jet's too small, causing the Spark Plugs to over heat. That truck would die quickly with no backfiring.
2.The big Resistor in the ignition circut cooked, and when warm, would open. Look for cooked wire terminal end's there too.
3. Hardest to find... The engine compartment wiring harness connects to the Cab harness in the firewall. I had some corrosion in that connector. It was a bugger to find too.
Dont try any darting across street's in front of traffic with this problem. It could get you killed.
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Several years ago I had a similar problem, after a few trips to the repair shop, they found that one of the female plugs to the ignition module was cracked. When the engine and pug heated, it caused the crack to open and loss of connectivity.
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