Fuel problem?
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Fleet Mechanic
Joined: Jul 2004
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From: va
Fuel problem?
1987 f150 4.9 efi I can only start the truck if i spray some starting fluid first.I think it runs on statring fluid only, it runs for 5 minutes. Black smoke at the exhaust the whole time. I unhooked the fuel line between the fuel filter and engine and i get a pint of fuel for 20 secs. on each tank. Just like the manual says. No fuel coming out of the regulator. Spark plugs are wet with fuel. Just installed a new fuel pump frame mounted. If i check for fuel at the return line will that tell me the regulater is good? Fuel relay good. fuel in tanks. I can here the relay click and i can hear the fuel pumps come on in the tanks. Can it run at all if the computor is bad?
Postmaster
Joined: Oct 2004
Posts: 4,402
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From: Delisle/Vanscoy, Sk.
My 85 300 6cyl had the same problem when I got it. The carbwas burning rich and black smoke. The mixture screws were turned all the way in and it still poured gas through. I changed carbs and then it worked fine. The old one was shot. Might be what you need to do. I don't think it is the feul pump.
Postmaster
Joined: Oct 2004
Posts: 4,402
Likes: 1
From: Delisle/Vanscoy, Sk.
Opps you don't have a carb. I would then say you have a sensor not working right. Now that takes more doing in locating the problem. If you know anyone with those computers that plug into your vehicle. It will tell them right away or shortly after a run what sensor or computer on truck is a foul.
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Fleet Mechanic
Joined: Jul 2004
Posts: 1,552
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From: va
Bad computer
Originally Posted by LxMan1
I would suspect the MAP sensor. Make sure that it has good vacuum going to it. If so, it could be bad. Without vacuum, it will run full rich!
