Injectors Hung open.
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Postmaster
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From: Broken Arrow , OK
Injectors Hung open.
What would make the injectors in a 1987 F 150 EFI 302 stay open?Anytime the key is on and the pump is running the cylinders are filling up with fuel regardless if you are cranking the motor or not.
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Joined: Jun 2006
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From: Ottawa, Ontario
Or the computer is fried. Does the pump run continuously? If so that's another indication the computer is done. Maybe disconnect the computer(first disconnect the battery) and see of the injectors still hang open, if not you found the problem.
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From: Broken Arrow , OK
OK , so we unplugged all the inj's. Now when the key comes on the fuel pressure gauge still only shows about 45psi and it drops off instantly when the key is turned off. We havent turned the motor to see if the cylinders are still filling up , but, there are no leaks in the fuel system. IOW's there isnt a visible puddle of fuel or a leak anywhere.
What I am having a trouble grasping is the truck has 8 inj's. What are the chances of all 8 being clogged at once? The problem just came on all of the sudden. It wasnt like it started running bad and then got worse. It just all happened at once.
What I am having a trouble grasping is the truck has 8 inj's. What are the chances of all 8 being clogged at once? The problem just came on all of the sudden. It wasnt like it started running bad and then got worse. It just all happened at once.
FTE Legend
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From: Ottawa, Ontario
About the same as you winning the lottery! It only takes on stuck-open injector to drain all that fuel however, so start pulling spark plugs looking for the one that is soaking wet.
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Postmaster
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From: Broken Arrow , OK
We did and they all were. Once we pulled the plugs and cranked the motor. Somewhere around 6-8 oz of gas sprayed out of all the cylinders. In fact some were so full it came running whenever the plug was pulled. We discovered this was happening when trying to crank the motor and it wouldnt budge. We decided to check for liquilock before continuing to try and spin the motor.
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FTE Legend
Joined: Jun 2006
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From: Ottawa, Ontario
But that was before you electrically disconnected the injectors right? You're going to have to go back and check them all again now. BTW.. the fuel pumps should not run continuously when the key is on either, should only run for a second and then shut off again until the engine is cranked. That indicates either a shorted fuel pump relay or a shorted computer... which could also be what caused the injectors to get stuck open in the first place.
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