Krafty
New member
This is a step by step guide on how to locate the source of your no fuel pressure problem on your fuel injected fords. some of the general testing information can also be applied to other non bronco and even non ford vehicles. This was a response to a no fuel pressure situation on an 89 bronco.
1- When you turn the Key to ON do you hear TWO PUMPS? (Note the Paragraph at the bottom about 87-91 vs 92 and up Fuel systems)
you need another set of hands so you can be under the gas tank to listen for the two pumps when the key is turned.
the Loud one is the high pressure pump on the frame rail under the drivers seat ( easy to hear) the second is the low pressure pump INSIDE the tank.
YES go to #2 NO go to #3
2- you can hear your pumps, but you still have little or no pressure on your fuel rail. Replace your fuel filter and your fuel pressure regulator on the fuel rail and check for pressure. turn the key on to run the pumps while the filter is off to flush out the fuel line,
Do you have pressure now?
Yes- it should run NO- you may have a dirty pickup in the tank ( rare).
3- If you dont hear both pumps then you need to do some testing, with a volt meter check for voltage at the pumps in the first 2 seconds after the key is turned on, check it a couple of times to ensure a consistent reading.
Do You Have Voltage at Both pumps but one or both are still not working?
Yes- #4 No - #5
4- if the pump or pumps are not working but there is voltage then replace the pump(s)
5- First check the inertia switch on the driver side, up aginst the fire wall to the left of the brake pedal or behind the right kick pedal.Push the reset button on the top of the switch to compete the circuit.
re check for voltage, if its a no then you need to test for power before and after the relay. no power before = no signal from eec, no power after = relay or relay plug.
I must clarify that only on the 87-91 efi vehicles (including F series and E series) these systems have the low pressure pump in the tank with the high pressure pump on the frame rail with the fuel reservoir with vapor recovery systems between the low pressure pump and high pressure pump, the fuel filter on these models is typically found after the high pressure pump just below the firewall. The 92-96 (and up)efi systems only use ONE pump which is a high pressure pump in the gas tank, the fuel filter is also on the frame rail but closer to the fuel tank. these vehicles have a vapor or excess fuel line that runs right back into the tank instead of having a fragile plastic reservoir on the frame rail.
adjust your diagnostics accordingly
1- When you turn the Key to ON do you hear TWO PUMPS? (Note the Paragraph at the bottom about 87-91 vs 92 and up Fuel systems)
you need another set of hands so you can be under the gas tank to listen for the two pumps when the key is turned.
the Loud one is the high pressure pump on the frame rail under the drivers seat ( easy to hear) the second is the low pressure pump INSIDE the tank.
YES go to #2 NO go to #3
2- you can hear your pumps, but you still have little or no pressure on your fuel rail. Replace your fuel filter and your fuel pressure regulator on the fuel rail and check for pressure. turn the key on to run the pumps while the filter is off to flush out the fuel line,
Do you have pressure now?
Yes- it should run NO- you may have a dirty pickup in the tank ( rare).
3- If you dont hear both pumps then you need to do some testing, with a volt meter check for voltage at the pumps in the first 2 seconds after the key is turned on, check it a couple of times to ensure a consistent reading.
Do You Have Voltage at Both pumps but one or both are still not working?
Yes- #4 No - #5
4- if the pump or pumps are not working but there is voltage then replace the pump(s)
5- First check the inertia switch on the driver side, up aginst the fire wall to the left of the brake pedal or behind the right kick pedal.Push the reset button on the top of the switch to compete the circuit.
re check for voltage, if its a no then you need to test for power before and after the relay. no power before = no signal from eec, no power after = relay or relay plug.
I must clarify that only on the 87-91 efi vehicles (including F series and E series) these systems have the low pressure pump in the tank with the high pressure pump on the frame rail with the fuel reservoir with vapor recovery systems between the low pressure pump and high pressure pump, the fuel filter on these models is typically found after the high pressure pump just below the firewall. The 92-96 (and up)efi systems only use ONE pump which is a high pressure pump in the gas tank, the fuel filter is also on the frame rail but closer to the fuel tank. these vehicles have a vapor or excess fuel line that runs right back into the tank instead of having a fragile plastic reservoir on the frame rail.
adjust your diagnostics accordingly
