If my '97 XLT (4.0 OHV) sits for a day or two it has trouble starting. It cranks fine but does not seem to be getting fuel. I can hear the fuel pump pressuring up the system when I first turn on the key. If I keep cranking the engine sooner or later it will start. When it does start it runs a little bit rough for a few seconds then runs fine. It seems to have more trouble when parked slightly uphill than when parked slightly downhill.
I'm suspecting that perhaps there is a check valve somewhere and the fuel is slowly draining back into the gas tank. I cannot find any check valve in any diagrams (I have the Ford service manual on CD). Is it built into the fuel pump?
1. Connect a fuel pressure guage to the fuel rail, watch it pressurize when you turn key on, 30-35psi
2. if low pressure before startup, possible bad FPR or fuel pump
3. monitor pressure, if it drops on startup, possible bad FPR or partialy plugged fuel filter.
4. check vacuum line on FPR, if wet with fuel replace
Thanks aquanaut. I went to Pep Boys and got a newer Hayne's manual but haven't had a chance to look at it yet. I talked to 3 employees and none knew anything about fuel pump pressure testing gauges. I found two gauges that said they were only for carburated engines. Where do I get a test gauge for this purpose and is this something that auto parts stores usually rent or loan?
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