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Brian, Auto Service Technician
Category: Ford
Satisfied Customers: 1227
Experience:  5 years Ford Technical Hotline/Service Engineer. 2005 Ford Master Cert. Automotive Technology degree
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1989 ford f250 cranks but will not start replaced the fuel

Customer Question

1989 ford f250 cranks but will not start replaced the fuel pumps and regulator.
Submitted: 7 years ago.
Category: Ford
Expert:  Brian replied 7 years ago.
The basic advice on any crank no-start is to find out if it is spark, air or fuel that is missing. It sounds like you suspected fuel was the problem. You did not say if testing was done to confirm that, though. If you can elaborate on what testing has been done, that would help.

The fuel pump relay and relay socket/wires often become corroded on these trucks. It would be a good idea to check the condition of these items and replace the socket and relay if necessary. The relay is located rearward of the air filter box. There are two relays mounted on a bracket, the green relay is the fuel pump relay.


Also, the fuel pump relay can be manually activated to test the relay and pump, by grounding a wire at the EEC test connector. The test connector is located in the same general area, on top of the fender apron.

The test connector is not plugged into anything, it is just laying there, sometimes it will have a protective cover on it. The plug end looks like this:
Use a piece of wire to connect that FP (fuel pump) terminal to ground (any metal surface on the body/engine, or negative battery terminal). When the FP terminal is grounded, the fuel pump relay should click, the fuel pump should run, and good fuel pressure should be present in the fuel rail. Use a fuel pressure gauge on the fuel rail test fitting to read fuel pressure.

For checking spark, use a spark tester to ensure there is good white/blue spark at the spark plug wire ends.

If no problems with fuel or spark are found, then it is time to check compression.
Customer: replied 7 years ago.
i have spark and my fuel pumps run and i have good presure in the fuel rail the intectors are not opening and i dont know why. is there a fuse or something that operates them? or maybe a relay that went bad for them???
Expert:  Brian replied 7 years ago.
The injectors are powered by the relay next to the FP relay. It is called the EEC relay (EEC=Electronic Engine Control or "computer"). This relay also powers the computer, and can be prone to the same problems I described for the fuel pump relay.

Each injector has a red wire that provides the 12v power, the other wire provides the ground. When the computer grounds the non-red wire, the injector should activate. So, make sure whether the red wires are getting 12 volts. If so, there could be a wiring problem between the injector connectors and the computer.

How did you check for injectors opening? There are LED "NOID" lights that plug in place of the injector and blink if the injector power and "pulse" is present.

I am including a wiring diagram, that shows the injectors. On this truck, the injectors are grouped into two "banks", so that four injectors pulse at the same time. The two banks take turns pulsing. So that means there are splices on the injector ground wires, and the splices sometimes can develop problems. The computer has two wires, one to control each bank. These two wires feed the ground to the splices.

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Customer: replied 7 years ago.
for the hell of it just to make sure i grounded out the fp and the relay didnt click and it sounds like something is raddling inside it like a stone or something. is it bad then? with no clicking and the stone sound??? but if i can hear my high preasure fp on the rail running how is it bad and how am i not getting gas in the cylinders????
Expert:  Brian replied 7 years ago.
The relay click may not be very loud, but you should be able to at least feel it click if you have a hand on the relay. Corrosion could cause a loss of voltage to the pump. The pump can still run with reduced voltage, but may not be able to deliver adequate fuel to start the engine.

SInce you may be onto something with this stone noise, I recommend taking out the relay and inspecting the connection for signs of overheating at the terminals, which would be a sign of a bad connection due to corrosion.

Did you mean the relay was making the strange noise? Or the fuel pump? The relay should only make a single click unless the ground is not well connected and it keeps clicking on/off.

Also, when the relay is disconnected, you will see two terminals in the socket that are larger than the others. These two terminals can be jumped together with a wire to deliver power to the fuel pump. This bypasses the relay and should cause the pump to run strongly with full battery voltage measurable at the pump. See if the engine will start with the fuel pump relay bypassed. Be careful when using the jumper wires, you can spread apart the terminals by jamming the wires in there, and that can result in a loose connection when the relay is reconnected. If you have some crimp-on terminals that match the fuel pump relay terminals, use the crimp-on terminals to make a jumper wire; that would be ideal.