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fuel problems

Old Jun 13, 2010 | 09:46 PM
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fuel problems

hello everyone, I cant figure out what is the problem with the fuel. If i leave the fuel pump connected it wont start and starts to smell like gas. Then I unhook the fuel pump and crank it for a while it will start and run for a will. Once a hear the engine running out of fuel i hook up the fuel pump and it run real rich. I changed out the fuel pumps, fuel pressure regulotar, fuel reservior, and some relays.
 
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Old Jun 13, 2010 | 10:08 PM
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First off, welcome to the site! (<---Grey can complete this one later)
Sounds like you have something on the fuel lines, did you replace the fuel filters?.
 
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Old Jun 13, 2010 | 10:35 PM
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yes i replaced it. To me it seems that the injectors are staying open for some reason. I also switched the ucm. It seem like the regulator is not controlling the pressure and it is leaking fuel to the injectors.
 
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Old Jun 14, 2010 | 12:06 AM
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When you replaced the regulator are you certain you got the fuel lines back as you found them. This sounds like the lines to the fuel rail have been switched somehow.
 
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Old Jun 14, 2010 | 04:18 PM
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I checked the fuel lines and they seem to be alright. The pressure line goes from the tank to the resovior to the pump,filter,and to the fuel rail. It was working find till i took off the upper manifold to replace the intake gasket. I also installed the egr system because i had cancelled it. I never touched the fuel line or any part of the fuel system. So now it wont start with the fuel pump conected and its gas like its getting to much gas. If i stop the engine and disconnect the pump and crank it will start right up. Then i connect the pump again.
 
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Old Jun 14, 2010 | 04:58 PM
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Maybe you got the wrong regulator?
 
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Old Jun 15, 2010 | 09:54 PM
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I've gone through 3 pressure regulators. It makes no difference. It still wont start with the fuel pump on.
 
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Old Jun 16, 2010 | 07:46 AM
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I heard someone with a similar issue, he mounted the fuel filted backwards.
 
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Old Jun 22, 2010 | 08:10 PM
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Today i was messing with my bronco and found out if i press the pedal all the way down it starts. But then alot of black smoke starts to come out the exhaust. what could this mean i have to press the gas pedal all the way down? its efi.
 
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Old Jun 22, 2010 | 11:54 PM
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It's just another indication that your Bronc has a bad over-fueling problem. For most EFI systems, if you floor the gas pedal and hold it down while cranking, the computer turns off the injectors, so a possible flooding problem can get cleared out. By the engine pumping air through, with no fuel added.

Once it starts and the PCM sees the engine is running, it drops out of the "clear out" mode, and enables the injectors again.

If I had your Bronco in my driveway, this is what I would try:

Attach a fuel pressure gauge to the monitor port on the fuel rail.
Turn key to RUN, not START, and let the fuel pump run for its couple of seconds before the computer shuts it off. See what the fuel pressure is.

If it is WAY OVER 45 pounds, I would suspect the fuel pressure regulator. But since you've already changed it out multiple times, I would then suspect that the fuel return line from the FPR end of the rail to the tank is plugged. The FPR is a shunt regulator. That means it bleeds fuel back to the tank via the return line to regulate pressure. If pressure drops too low in the rail, the FPR closes down, bleeding less fuel to the tank so pressure in the rail builds. And vice-versa, if pressure in the rail goes high, the FPR opens up wider and shunts more fuel back to the tank, dropping the rail pressure.
If the fuel return line is blocked, there is no way fuel pressure can be bled off back to the tank, so pressure goes very high with the fuel pump running.

If fuel pressure does not get up to about 38 PSI or so, turn key OFF then ON again to restart the fuel pump. If within about 3 tries of doing this you get about 37 - 43 PSI, stop and watch the gauge needle. If the injectors are not leaking, the pressure should stay up for a long while, and slowly bleed down over an hour or so. If it drops right away, then injectors are leaking, or for some reason they are being turned on, and they should NOT be. You could carefully unplug the electrical connections to the injectors and try it again to see which it is.

If you can never get the pressure on the gauge up anyway near 37 PSI, then I suspect that leaking injectors are leaking so bad that it is just flooding the engine really bad. There again, could carefully unplug their electrical connections to find out if it is the injectors themselves leaking badly, or if the PCM is telling them to be ON.
 
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Old Jun 23, 2010 | 11:08 AM
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when you replaced the computer did you get the exact same year computer? have you pulled any codes yet?

there is a vacum line that runs over to the FPR, if you pull that out is there gas present?

Torky2's suggestions are also valid
 
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Old Jun 23, 2010 | 04:08 PM
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It was already having problems before a switched the computer and it was the same year. I put my old computer back and still the same problem. There is no fuel present went i pull the vacum line off or does it start missing. Once i let it run for about 3 minute it runs perfect. Its only the starting part. I have to press the pedal all the way down so it can start. once it starts alot of black smoke comes out and it sound like its running on 4 cyclenders. I keep it at bout 3000 rpms till it starts running gud. If I dont Press the pedal it wont start.
 
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Old Jun 23, 2010 | 05:55 PM
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so have you pulled codes.
 
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Old Jun 23, 2010 | 06:52 PM
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What color is the plastic on the injectors??
 
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Old Jun 23, 2010 | 07:20 PM
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I cant pulled any codes. I took it to autozone and they told me that they didnt have a code reader for that year. Only 96 and up. The injector im running are from msd ignition. I can remeber the part number but the color is gray and black. I had them for a couple of years and no problems. Im thinking it might be the return fuel line. I replaced the fuel line going from the tank to the fuel pressure. I just need to replace the return line and see how that goes.
 
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