Starting missing and backfire when gased

[badriand]

Truck was running fine then all of a sudden it started to miss and backfire when i get on gas more like it is starving for fuel. I check hei cap and looks dry and took carb off and no trash. Also replaced the inline filter. Any ideas. Haven't pulled plugs yet.
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[lakeroadster]

Replace the distributor cap. I had one that was cracked and was doing the same thing.

[Indian113]

Do you have any plug wires shorted out?

[charx2]

I had a similar problem and it wound up being my plugs, I didn't really know what I was doing and it took me 2 weeks to find it was my plugs fouling(they were brand new). On the upside, I learned how to time a motor and earned a little more experience so now I am a half-assed shade tree mechanic!
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[Turkey]

My dad always told me not to just change one thing. Always change the plugs, distributor cap, rotor, points, and condensor that way you don't chase your tail trying to figure out a $2.99 problem.

[Tommy454]

Take a look at the fuel pump. There is a weep hole on the left side. If the diaphram is bad it most likely will be leaking fuel and sucking air; that will give you the symptoms you are experiencing as well as the the above posts. Good luck!

[irish1966]

Originally Posted by tommy454

take a look at the fuel pump. There is a weep hole on the left side. If the diaphram is bad it most likely will be leaking fuel and sucking air; that will give you the symptoms you are experiencing as well as the the above posts. Good luck!

x2

[pctahlequah]

Mine started the same thing thursday. Think mine is a gas fouled spark plug, tho. My carb is prone to flooding on a cold start.
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[badriand]

Replaced cap and the plugs and wires look normal. Since it started the other day I haven't driven it other than backing out of the garage today and it seems to have gotten worse. It will not idle anymore and sounds like it isn't getting hardly any fuel. I pulled the fuel line and ran it into a bucket and turned it over and it looked like it was just pulsing gas. Also exhaust is dropping black deposits, since it sounds like a cat hissing now. Think the fuel pump is bad?
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[Tommy454]

A 1/2 hour change out time and a $20.00 part.... sounds like you got lucky!

[badriand]

[quote]

A 1/2 hour change out time and a $20.00 part.... sounds like you got lucky!

I hope it is only the pump.

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[Tommy454]

If the fuel is surging from the pump ; its done.

[bama63]

x3 fuel pump

[badriand]

Will swap tomorrow and see thx.
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[neto]

If its throughing out black deposits out the tail pipe, sounds to me like it's running rich then when you give it gas you worsen the problem. When you say the carb is clean did you take it apart? Adjust your air fuel mixture screws and see if it helps. Might just be your float level is high due to a leaking needle or dirt stuck on it keeping it open. How did the plugs look?
Good luck.

[badriand]

Black is when i shower down on it. I took carb apart and it was clean. Plugs look normal they didn't looked fouled, maybe a little carbon build up.
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[NCD1966]

i was having the same problem with my 305 V8 . Luckly I had extra good parts laying around like distributors, cap, rotor, and even put a different carb. Also change the plugs and check the timing. Still ran like just like you described.

I never thought about the fuel pump.
my solution was: I was in the process anyway of putting a 350 with cam and heads so I pulled the 305 out. And that took care of the problem. Also took care of the weak 1987 305 v8

[badriand]

This is for the birds. Hate it when one sec everything is fine and the next I am chasing my tail. Replaced cap, fuel filter, pump checked carb n needles. Still does the same thing.
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[irish1966]

Originally Posted by badriand

This is for the birds. Hate it when one sec everything is fine and the next I am chasing my tail. Replaced cap, fuel filter, pump checked carb n needles. Still does the same thing.
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Did you change the pump? If you did, did u check the pressure of the gas from it? I know that if the pickup gets blocked it can cause issues also. Just something else to throw in to your already irritating mix.

[Rich 5150 69]

How`s the fuel pump shot from the carb? And I would suggest maybe looking at vacuum advance, broken diaphram.

[jonzcustomshop]

my 65 has the same symptoms.. from checking the dizzy alignment, it looks like it jumped time.
is that a possibility?

[badriand]

My buddy who is a mechanic finally got around to calling me and heard me out and listened to it over the phone. He said sounded like distributor had moved or electric control module maybe bad or bad gas. After talking about it, it seemed like the coil pack had set a little further up than I had remembered. I retarded the distributor and it cranked up and ran fine for about a block then it started sputtering all of a sudden. Just went a head and parked it for the night but I think the vacuum for tranny may have worked loose now since I had just been adjusting the distributor. I will look that over tomorrow.

Forgot to add I put 2 fuel pumps on today. The first one where the weld on the bottom of the pump is to hold the outlet fuel line snapped right off on me when i was tightening the threads. Guess that wasn't made to good.
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[neto]

Well if it ran fine for a block then you are in the right area where to start looking. I guess back to check timing and distributor.

[slaminum69]

Had a similar problem with my 63, after replacing the fuel pump, plugs and wires and set the timing she ran great at idle, but when i gave it gas she would hesitate and stumble, well it ended up being the rubber fuel line coming out of the tank (underneath the cab of the truck) that connects to the main fuel line to the pump. It had a crack in it, didn't leak or anything, but when you gave it gas it would flex enough to suck in air and give me that missing feeling after replacing it no issues. Give that a shot and hopefully it helps you out!

Dennis

[budden]

did it pull a valve stud