Another Cutting out problem
Thread Starter
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Fleet Mechanic
Joined: Nov 2004
Posts: 1,857
Likes: 5
From: Northern CA
Another Cutting out problem
I have a '69 F100 2WD 390 C6, pretty much stock. Newly acquired and am having problems with electrical while driving. Occasionally at first startup it gallops along like it's running on 4 cyl for about 5 sec then idles Ok. This morning I decided to take it to work (50 mile drive) and had repeated episodes of the thing cutting out. The tach would drop to 0 while driving but if I gave it the gas it would fire back up. It never did die completely, except once at a stoplight, but started right up again. I'm fairly good mechanically, I've replaced everything in the ignition/charging system except the coil. but I'm wondering if a vacuum/carb issue may be causing this. Should I go ahead and replace the coil, or look at the fuel system?
I need a little guidance here, PLEASE?? Anything!! This FE needs to be a little bit more reliable...
Did I say PLEASE HELP??
Thanks,
bryyce62
I need a little guidance here, PLEASE?? Anything!! This FE needs to be a little bit more reliable...
Did I say PLEASE HELP??
Thanks,
bryyce62
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Joined: Jan 2001
Posts: 57,025
Likes: 2,756
From: Virginia
A clue that it would be a carb problem would be black smoke out the exhaust when it was throwing a fit. Another clue would be if you can pat the gas, and it clears up for a second, but then reverts back to missing(dirt in one of the main jets).
A very rare problem that sometimes happens with the ignition, is the wire that goes from the coil to the points gets a break in it. It constantly moves inside the dist, because the advance of the dist moves the points plate back and forth. On rare occasions, the wire will break inside the insulation, and when the plate moves, it will make the ignition cut out(not run on 4 cylinders, but cut out completely).
A very rare problem that sometimes happens with the ignition, is the wire that goes from the coil to the points gets a break in it. It constantly moves inside the dist, because the advance of the dist moves the points plate back and forth. On rare occasions, the wire will break inside the insulation, and when the plate moves, it will make the ignition cut out(not run on 4 cylinders, but cut out completely).
Thread Starter
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Fleet Mechanic
Joined: Nov 2004
Posts: 1,857
Likes: 5
From: Northern CA
It definitely throws black smoke occasionally, there are marks all over my driveway...I'll check the continuity of the wiring when/if I get home tonight. But why would it take off again by mashing the gas??
Bryyce62
Bryyce62
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Joined: Jan 2001
Posts: 57,025
Likes: 2,756
From: Virginia
Most older cars and trucks have a little bit of rust in the gas tank. Flakes of rust and dirt can get in the carb, and cause lots of problems. If they caught in the float needle occasionally, then the carb will flood the engine with too much fuel. When they finally make their way into the float chamber, they will eventually get sucked into the main jets in the bottom of the fuel bowel. One jet can get plugged, which feeds half the engine. Patting or smashing the gas, makes the accelerator pump squirt fuel into the engine. This is fuel that engine needs because one of the jets is clogged, so it runs happily till that little bit of fuel is gone, then it reverts back to starving half of the engine, unless you pat the gas again.
Thread Starter
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Fleet Mechanic
Joined: Nov 2004
Posts: 1,857
Likes: 5
From: Northern CA
You know Dave, I think you're right. I've been chasing an electrical problem for 2 weeks and I think that it's been a fuel delivery prob the whole time. Also explains the 5mpg, black marks on my driveway and it running seemingly on 4 cyl at startup.
Can you say carb rebuild???
Thanks for switching on the light for me....
I owe ya one.
BTW this site is a gas...sure wish we had this internet thing back in the '70's. Can you imagine?
bryyce62
Can you say carb rebuild???
Thanks for switching on the light for me....
I owe ya one.
BTW this site is a gas...sure wish we had this internet thing back in the '70's. Can you imagine?
bryyce62
Thread Starter
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Fleet Mechanic
Joined: Nov 2004
Posts: 1,857
Likes: 5
From: Northern CA
just following up, did a R & R on the carb over the weekend. Boy, that old FE never ran so good. I thought that I had a low end knock that's now gone. Was getting really crappy gas mileage, that's gone, idles nice and smooth now and takes off like a jackrabbit.
Thanks again Dave, and thanks to this FTE website. Sure makes wrenching on these old Fords a lot more fun.
Bryyce62
Thanks again Dave, and thanks to this FTE website. Sure makes wrenching on these old Fords a lot more fun.
Bryyce62
