87 5.0 still missing
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87 5.0 still missing
1987 F150 with 302 has been missing pretty bad when I hit a hill with it. I have changed plugs, wires, distributor cap, rotor button and fuel pressure regulator. Also changed the TFI module recently. The miss is still there. I checked the fuel pressure today. With engine off and fuel pump grounded to run, I have 40 psi. With the engine running, the pressure is 32 psi. My manual says 30 to 45 psi while running. 32 seems a little low to me. When I pinch off the return line, the pressure shoots up drastically. Any ideas?
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From: The dark carnival
Originally Posted by 87black150
1987 F150 with 302 has been missing pretty bad when I hit a hill with it. I have changed plugs, wires, distributor cap, rotor button and fuel pressure regulator. Also changed the TFI module recently. The miss is still there. I checked the fuel pressure today. With engine off and fuel pump grounded to run, I have 40 psi. With the engine running, the pressure is 32 psi. My manual says 30 to 45 psi while running. 32 seems a little low to me. When I pinch off the return line, the pressure shoots up drastically. Any ideas?
The fact that the pressure shoots up when you pinch off the return line is a good thing...it's suppoesed to do that. How does the engine react to that added psi?
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Originally Posted by eco
Why do you think the engine has a missfire when under load?
The fact that the pressure shoots up when you pinch off the return line is a good thing...it's suppoesed to do that. How does the engine react to that added psi?
The fact that the pressure shoots up when you pinch off the return line is a good thing...it's suppoesed to do that. How does the engine react to that added psi?
Yeah, I know the pressure is suppose to do that. I wrote that so everyone would know that the fuel pump seems to be working OK. The engine will rev up slightly when the fuel line is pinched shut.
Last edited by 87black150; Mar 19, 2007 at 04:55 AM.
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