Fuel Injectors
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5th Wheeling
Joined: Jan 2008
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Fuel Injectors
I have an 89 Bronco II 2.9 that once started almost immediately now have grind on it awhile or give it a shot of starting fluid then it cranks. I have read someplace that when you first turn the key on all the injectors get voltage to put some gas before the starter is engaged. Is this true and if so how do I check to see if this is happening? How can it be fixed. Thanks for the help.
Duncan
Duncan
Postmaster
Joined: Dec 2001
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From: UT
Never heard that before. What I do know happens is the fuel pump is powered for a couple of seconds after turning the key on to pressurize the fuel system. There's a check valve somewhere that is supposed to keep the system pressurized while waiting for it to start. When that check valve goes bad, it allows the fuel pressure to bleed off, which makes it hard to start. Put a fuel pressure gauge on it and see if the fuel system can hold pressure.
Elder User
Joined: Feb 2006
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From: SE Michigan
Another thing that could have happened is that a pin hole leak could have opend up on the short piece of rubber fuel hose that runs from the pump to the metal line inside the tank. This small leak isn't enough to make the pump keep running to build up pressure when the key is first turned on. But it will make it not supply enough pressure for starting when you actually crank it over. So you have to keep cranking till it starts. This is what was going on with my 91 Ranger recently. When I got the pump & sender unit out of the tank I didn't see the bad spot in the small hose at first. But after it dried off on the out side of the hose, one place kept getting wet again and that's where the pin hole was. There are two other possibilities. One is the fuel pressure regulator isn't working right or the pump just isn't making the pressure it should. But from what I've seen in the past, that little fuel hose will go bad way before the pump or regulator does.
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5th Wheeling
Joined: Jan 2008
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I put a pressure gauge on it this weekend and when the switch is turned on it puts up 20 psi and holds it. When the engine starts it is about 33 psi. Is this normal? I am thinking pressure regulator isn't working properly.
Postmaster
Joined: Dec 2001
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From: UT
What does the pressure come up to if you click the key back off and turn it on again? If you do it multiple times, will it come up to 40 psi? What does the pressure come up to if you ground the fuel pump test lead in the self-test connector so the pump runs continuously? 20 psi is too low, it should be more like 40 psi. 33 psi KOER is about right. Basically it looks like the thing is hard to start, because it's taking longer than normal for fuel pressure to come up to spec.
