1987 Ford f150 xlt efi 5.0


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Old 04-16-19, 06:48 AM
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1987 Ford f150 xlt efi 5.0

If any one could help me with a problem I'm having on my 1987 Ford f150 xlt efi 5.0 I'm having problem's with the external fuel pump the problem I'm having is the external fuel pump is supposed to run for a few seconds then shut off after it primes up but it's not shutting off it continues to run and not shut off after it primes up and it's fuel locking the engine it'll shut off if turn the ignition switch off I've changed the fuel pump relay I've changed the ecm I don't know what else to do I been looking for help on this problem but can't seem to get the help
 
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Old 04-16-19, 08:44 AM
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the pump staying running should not fuel lock the engine for that to happen your injectors would have to be open or your fuel pressure regulator could be bad and is leaking fuel back through the vacuum line, the pump will run anytime the engine is running if it is running all the time usually its due to the fuel pump relay sticking but this alone will not flood the engine but will eventually run the battery dead.
 
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Old 04-19-19, 05:43 AM
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I can't even get the engine started cause its dumping so much fuel

That's the problem I can't even get the engine running cause its dumping to much fuel and fuel locking the engine
 
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Old 04-19-19, 05:57 AM
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Not running

The engine isn't running and the fuel pump is steady running and not shutting off like it should after it primes up
 
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Old 04-19-19, 11:20 AM
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like I said in the previous post there is something leaking, the fuel pressure regulator was a common problem on older fords the diaphragm would go bad and push fuel through the vacuum hose into the engine to check it you only need to remove the vacuum line from the fuel pressure regulator and turn the key on if it sprays gas out it is bad replace it, if its not a regulator it may be an injector stuck open not a common problem but it is a old pickup, you will probably have to remove all the spark plugs and crank the engine over with the plugs out to get rid of excess fuel in the cylinders and probably have to change the oil also once you figure out what the problem is and get it running as it is likely to have to much gas in it.
but the fuel pump only supplies pressure to the fuel rail the regulator regulates pressure to around 40 psi and returns any extra back to the gas tank if its working properly, the fuel pump does not cause an engine to flood you said it goes off with the key so someone may of wired it to the ignition switch but the point is its not causing your starting issue you have a regulator maybe an injector problem might even stick a noid light in at injector harness to make sure the ecm is not commanding the injectors on all the time its unlikely but a possibility.
 
 

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