302 hesatating
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Fleet Mechanic
Joined: Apr 2007
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From: patricia ab canada
302 hesatating
ok i need some advice.while driving to pick my daughter,my 81 302 2v.it started ok, ran great till the temp got up to operating temp,then the truck started to jump and lose power.it would only go to 2000 rpm for about 25 miles,sat and idled for a few minutes,pulled out of town,ran great.about 2 miles out of town it started acting up again for about 10 miles and ,then ran great again the rest of the way home. now i have rebuilt the carb,replaced the fuel filter and i just installed i new tank selector valve.both tanks are at half.now my question is, is the fuel pump crapping out.i don't think the carb is icing.i have also put a 1/2 can of seafoam in each tank. plus new cap &rotor ,plugs,wires.new exhaust no cats and manual choke as well. any ideas??????????????
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Fleet Mechanic
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From: patricia ab canada
i know it's not the pickup tube,when i replaced the tank selector valve the gas was siphoning out of both fuel lines covering me in gas.if my pick UPS had holes it wouldn't siphon..i thought the same too.with the tanks full runs great,when tank goes empty and i switch tanks it happens.that's why i changed the selector valve.found out old one was only opening half way,so it drawing from both tanks when switch to front.I'm going to check filters today ,maybe replace fuel pump on Friday. could it be vapour lock????
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From: Virginia
If you have a fuel delivery problem, you will not notice it at idle and cruising as much as when accelerating and pulling a hill, when you use the most fuel.
If it runs ok at first, and starts acting up when it warms up and in town driving, it may be the ignition module starting to fail. They are known for heat related failures.
If it runs ok at first, and starts acting up when it warms up and in town driving, it may be the ignition module starting to fail. They are known for heat related failures.
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Fleet Mechanic
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From: patricia ab canada
it idles perfect.when it acts up.if i pull over and let it idle,it pulls strong till i get into 3gear then it starts all over again.town driving seems ok with start and stop,just highway travel.thats why i think it might be vapour lock.the drivers side exhaust runs outside the drivers side frame,about 6".muffler about 2" from frame,oppisite of selector valve.
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Joined: Jan 2001
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From: Virginia
If the fuel system is all original and routed the way the factory had it, then vapor lock should not be a problem. Vapor lock also rarely happens on the highway, when there is lots of air moving by the components. Vapor lock will usually happen on a hot day, sitting around idling at stoplights in town.
One scenario were the fuel system can overheat on the highway is if the exhaust heat riser is stuck shut. This will force too much exhaust under the carb area and the fuel in the carb can start to boil.
One scenario were the fuel system can overheat on the highway is if the exhaust heat riser is stuck shut. This will force too much exhaust under the carb area and the fuel in the carb can start to boil.
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Fleet Mechanic
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From: patricia ab canada
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Methanoholic
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From: Maine (NorCal Native)
I agree, If it siphoned, there no air getting in, BUT were the tanks full or close to empty at the time.
Just trying to cover the bases!
-Enjoy
fh : )_~
Just trying to cover the bases!
-Enjoy
fh : )_~
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Fleet Mechanic
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From: patricia ab canada
OK yesterday i filled both tanks and the same thing.but i noticed when i started the truck,there was quite a bit of water coming out of the tailpipes,until she was up to operating temp,then nothing.if i let it idle a minute or too,it runs strong,then a couple of miles it does it all over again.the motor is not detonating so i don't think it's lack of fuel. i'm wondering if there is water in the fuel,or could the fuel pump be on it's way out,or like franklin said ,the duraspark be faulty?would like to narrow it down and not spend a ton of cash on stuff that won't help or don't need.thanks
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Fleet Mechanic
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From: patricia ab canada
ok i changed the filters,put in an electric fuel pump.still same won't rev past 2000 rpm.i'm beginning to start it's the ignition.now is there a way to check it with out buying a new one.i don't think we have a place here that will test them.or will i have to bite the bullit and buy one.or could it be something else.i need help guys.this is my daily driver.my wife will kill me if i take her car. and my 86 is just to hard on fuel to run into town everyday. thanks
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Fleet Mechanic
Joined: Apr 2007
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From: patricia ab canada
just rebuilt carb couple of weeks ago. there is a filter one the carb inlet,that i replaced yesterday.i was just wondering if i have a blockage in the steel line between the selector valve and the fuel pump.i guess i can pull the top of the carb off and check,easy enough.thanks for the tip.