I have a 1986 f-350 with a 460........carbed.... recently the motor would all in the sudden loose power and sometimes stall while driving. Sometimes it let's out a hell of a backfire out the carb when it does, almost like if you shut the ignition off while you were driving and turned it back on again. I brought it in and had it tuned and the filters changed. No difference. The last time it stalled I couldn't restart it and I noticed the fuel gauge went. I had it towed to ford and had them check it out. They called me and told me that it needed two fuel pumps???(the truck only has 1)......after they changed the pump, replaced the tank switch and valve........and charged me 600 bucks..........i got the truck back and it is doing the same thing. I called them and asked them what the hell they did because they didn't fix it, that's for sure!!! Where the engine is backfiring, my suspicion is that the problem is electrical. Possible the electronic ignition module??? After spending almost 1000 dollars on a 15 year old vehicle to fix something that seemed rather simple..........I am at a loss. I have it back over to another mechanic to see if he can find the problem, so I can bring their invoice over to ford and somehow be compensated for 600 worth a repairs that did jack #####. If anyone has any ideas to help..............please do!!!!!!!!! I had a new clutch put in it by ford about two months ago.......if that may have anything to do with it.

 

i dont know if i can help but it seems it just time to step back and take a deep breath. it would not hurt if you went back to the basic. first take the time to do a compression test or leak down test. which ever is easier for you.compression make sure you pull all the plugs and wire open your carb and use a batery charger on your battery so you have the same amout of juice when you do each crank you should not very more than 20 pounds but i like to see within 10 pounds.need to eleminate any internal problems. Next check plugs take you truck out and drive it on a lonely road make sure its warmed up. when it back fires or dies shut it down and take the time to inspect all your plugs look for the odd man out if all look a little black and one looks wet or white start traceing from there.your plugs should be tan color (inthe real world) but you looking for some out of place. Make sure your timming is correct. your choke operates like it should. check all your wires located around the distributor look for cracks in wires also look for any old vacuum lines. you just might have one that moves just right during anygiven time causeing you engine to go lean a back fireand die.make sure you weights and springs in your distributor are functioningcorrectly. hope this will give you some ideas take you module to someone to test it i had one that gave up on me soon as i got to about 3500 rpms it would cut out and die replace it took car of the problem good luck

 

when talking about the pumps........the parenthesis was supposed to say it only had one replaced.........not one pump...........derr

 

Have you checked the engine to body ground strap?
Had a Mustang with a loose strap and on a left turn would cut out. If all gauges go out this might be the place to look.

 

I have a recently purchased 69 F100 w/ a 390. I did a top end rebuild on it. When reassembling the accesorries, I had my alternator pigtail too close to the exhaust manifold. This exposed the power lead leaving the alternator. A couple of times until I realigned the alternator, I had that wire ground on the exhaust manifold. This killed all electricity on the truck. Simply moving the wire clear got me going again. Also the wire that provides the coil with current was old and had breaks in it's insulation. While starting to break in a new cam, it chose to become intermintent. This killed the motor as well. Here I just spliced in new wire. In each case however, the engine died without backfireing. The duraspark box is pretty cheap and it wouldn't be a bad idea to carry a spare.

 

i have an 87 ford and it did the same this and it was the coil

 

Lead wire leading from the distributor to a connector leading to the electronic ignition module was arcing with another exposed wire............shorting out electronic ignition..........horray

 

Don, My '88 E-150, 302 has been doing exactly what you have described. I put up a post and
received, many great possible answers to my
problem. While checking along the drivers side
frame rail, looking and wiggling for a problem
in the wiring harness. I came across a round
bottemed filter assembly, between the gas filter
and the gas tanks. It was dripping a small amount of gas, after buying a filter for $8.00, I tossed the filter out, as the filter assembly was empty.
And replaced the O ring gasket, in the filter assembly, screwed it back on, an tighten it up with a oil filter wrench. Drives great now!

 

Hmmm, I've always wondered how many sets of wires could be bought for $600.00. You could have given these five guys $100.00 each, fixed your problem, AND had enough left over for at least one set of wires and lunch! OUCH!

 

Mike @ #7 had the same thing I DO !!
IF you have 2 tanks, NOBODY will tell you that there's aNOTHER fuel filter behind the main pump on the rail under the drivers door.Its a nonelectric 'tankswitching solenoid thingie.4 lines in, mainline out to front pump (plus returnline)
Its in a black seriousplastic housing that looks like the bottom COULD screw off with an oil filter wrench..
well it does, and theres a 6$ sediment type filter arrangement in there.

water rust, ugly muck..was the prettiest thing I've ever seen..

AFTER spending 600$ and 3 weeks just like you