86 302 efi HELP!!!!!!
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New User
Joined: Oct 2006
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From: mankato, mn
86 302 efi HELP!!!!!!
I just bought a 86 f150 runs and drives great but it has a hole in the rear tank and the previous owner said when ever he drove it it would just die while going down and he would let it sit for a half gour and it would start right he called it vapor lock but i thought that was when the fuel gets to hot but not sure and it did it to me the other day it just dies no spudder or anything does this sound right? And will it fix it with a patch it cuz i have heard of people just not using that tank and they drive every day?
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Joined: Nov 2007
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From: Denver Metro Area, CO
Just dying without any sputtering sounds to me more like ignition than gas, and I've
heard stories of ignition modules failing when they get hot. Next time this happens,
check for both gas and spark (though I don't know how to check for gas on an
engine with EFI but somebody here will help you). In any case, I don't think a hole in
a gas tank will cause your problems.
-ct
heard stories of ignition modules failing when they get hot. Next time this happens,
check for both gas and spark (though I don't know how to check for gas on an
engine with EFI but somebody here will help you). In any case, I don't think a hole in
a gas tank will cause your problems.
-ct
Post Fiend
Joined: Jul 2004
Posts: 8,786
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From: Northern California
I would say that this was the problem.
And I recomend getting the gas tank fixed or swapped with a new one asap.
And I recomend getting the gas tank fixed or swapped with a new one asap.
Senior User
Joined: Feb 2008
Posts: 122
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From: El dorado, Arkansas
I have both
I have good news for you, I have both an ignition module and a good rear tank. Both from an 86 F150 with a 302. I would have to find the Ignition module but I know I have one. If you are interested let me know. I am pretty sure that both the sending unit and fuel pump in the rear tank still worked also. Make me an offer. You would have to pay the shipping though.
New User
Joined: May 2008
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put a can of starter fluid in the truck, next time it quits give it a little sniff, (just a short shot!!) if it starts and quits its fuel, if not its ignition or, carry a spark tester, when it quits put it inline on a spark plug and make sure its in neutral, switch on, short the solenoid with a old screwdriver, if it shows fire then its fuel if not get the module and put it on
and like 81-f-150-explorer said, get that tank repaired, it will cause many problems
and like 81-f-150-explorer said, get that tank repaired, it will cause many problems
Senior User
Joined: Feb 2008
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From: El dorado, Arkansas
Checking fuel
On the fuel rail, can't remember which one, there should be what looks like a valve stem for a tire. If you are by yourself, turn the truck over a few times, then take the cap off of the valve stem looking port. Push in on the stem inside and if the motor is getting fuel it should have pressure on it. Watch your eyes. If there is pressure it will sometimes spray pretty hard. I put a rag over it then push it in to stop the fuel from getting everywhere. If you have someone else there they can turn the key on while you hold the stem in. When the key is turned on the pump kicks in for a second and you should get pressure at the fuel rail. I can't remember all that you said you checked but on the 86 parts truck that I have I know it actually has 2 fuel filters on it. I have dual tanks. The second, and less known filter is on the inside of the frame rail below the drivers door. You have to unscrew the casing and it has one of the open element filters inside. You could check and see if it is plugged. Anyway I hope this helps. I am listing the 86 parts truck that I have on the classifieds section on here. Check it out. I know I have some parts that you could use.
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New User
Joined: Oct 2006
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From: mankato, mn
I got a new ignition module and still dies, with no spark so its not fuel, could it be the coil going bad or??? im terrible with ingnition stuff ANY HELP WOULD BE GREAT WANT TO START BUILDING TRUCK FOR MUD DRAGS!!!! THANKS
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From: Virginia
I think I will put this in my signature. When troubleshooting a EFI engine, always pull the codes first
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From: sunny fla sometimes windy
A multimeter will help figure if the coils values are okay. So get one if you don't have one
IF it seems to be a heat related thing a can of keyboard duster or two kept in the
truck and go for a ride and when it dies, start by spraying the tfi module(side of dist)
for a good 7-10 seconds while holding the can upside down so the freon comes out and
then try strating the truck, no go? then pull off the cap and spray inside the distributor
for 5 or so seconds (let the freon residue evaporate) reinstall cap and try to start.
Basically you want to just go down the line and try to cool the components and when
it starts you can try to recreate the problem again or more then likely it was the last
component you chilled. Heat related failure or even just the resistance level changing
from heat is a problem. Cryodiagnostics!! Of course there is a high dollar can of stuff
you can buy that is made for diagnosing heat related failures in transmitters and
other stuff but for 2.99 you can do the same thing. Of course don't spray your fingers
wear eye protection and the time and amount of spray needs to be adjusted for some
materials since metal conducts better etc.
IF it seems to be a heat related thing a can of keyboard duster or two kept in the
truck and go for a ride and when it dies, start by spraying the tfi module(side of dist)
for a good 7-10 seconds while holding the can upside down so the freon comes out and
then try strating the truck, no go? then pull off the cap and spray inside the distributor
for 5 or so seconds (let the freon residue evaporate) reinstall cap and try to start.
Basically you want to just go down the line and try to cool the components and when
it starts you can try to recreate the problem again or more then likely it was the last
component you chilled. Heat related failure or even just the resistance level changing
from heat is a problem. Cryodiagnostics!! Of course there is a high dollar can of stuff
you can buy that is made for diagnosing heat related failures in transmitters and
other stuff but for 2.99 you can do the same thing. Of course don't spray your fingers
wear eye protection and the time and amount of spray needs to be adjusted for some
materials since metal conducts better etc.
Freshman User
Joined: Aug 2004
Posts: 33
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From: Phoenix,Az
ok, i have the same truck year model everything as this guy, and i have the same problem, but i think i know what it might be.
someone once told me that theres a valve switch between the 2 tanks and the switch on the valve is bad, or maybe it's just the fuel pump going bad.
someone once told me that theres a valve switch between the 2 tanks and the switch on the valve is bad, or maybe it's just the fuel pump going bad.
Thread Starter
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New User
Joined: Oct 2006
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From: mankato, mn
i guess i should have tried the starting fluid thing first cuz it will fire with it i just assumed it was ignition by the way it was shuting off, so i was wondering if i just cancel out the rear tank all together by just plugging both of the hoses that running to the front? or how would i o about doing it? thanks