99 5.4 Fuel Pressure - hard start/no start.
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Joined: Jan 2010
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From: texas
99 5.4 Fuel Pressure - hard start/no start.
1999 f150 4x4 5.4 254k
Symptoms:
Truck intermittently refuses to start with first turn of the key, turn ignition off then back on, confirm fuel pump charge then start right up. Has been doing this for some time. Now the truck has refused to start on at least three occasions within last two weeks, at all. First time disconnected battery and let sit for 20 minutes, truck started reluctantly but started. Purchased scanner (never pass up a chance to tell the wife that you need a tool to fix the truck!), had code off and on for some time now. O2 code, replaced (all, since it has 254k on it) and reset codes. Truck failed to start again, hooked up scanner, no codes? Cleared anyway and truck started after about 20 minutes. Similar instances have occured since. Truck runs fine while driving.
Checked fuel pressure:
With KOEO, pressure goes to approx., 35-40 then immediately retruns to zero within 5 seconds. This is not right? I believe it should hold for at least a few hours if not minutes, please correct me if wrong. With KOER, it reads approx., 20 at idle; I also believe this is wrong.
Question/s:
How long should pressure hold after initial key on charge from pump and what pressure should that be?
What is the acceptible range for pressure at idle and under throttle?
Haven't changed anything as of yet, did pull vacuum hose off regulator to confirm no fuel was present in line. Pump, relay and regulator are all original, fuel filter is changed regularly; you don't get to 254k without doing the maintenance...
Thanks in advance,
Symptoms:
Truck intermittently refuses to start with first turn of the key, turn ignition off then back on, confirm fuel pump charge then start right up. Has been doing this for some time. Now the truck has refused to start on at least three occasions within last two weeks, at all. First time disconnected battery and let sit for 20 minutes, truck started reluctantly but started. Purchased scanner (never pass up a chance to tell the wife that you need a tool to fix the truck!), had code off and on for some time now. O2 code, replaced (all, since it has 254k on it) and reset codes. Truck failed to start again, hooked up scanner, no codes? Cleared anyway and truck started after about 20 minutes. Similar instances have occured since. Truck runs fine while driving.
Checked fuel pressure:
With KOEO, pressure goes to approx., 35-40 then immediately retruns to zero within 5 seconds. This is not right? I believe it should hold for at least a few hours if not minutes, please correct me if wrong. With KOER, it reads approx., 20 at idle; I also believe this is wrong.
Question/s:
How long should pressure hold after initial key on charge from pump and what pressure should that be?
What is the acceptible range for pressure at idle and under throttle?
Haven't changed anything as of yet, did pull vacuum hose off regulator to confirm no fuel was present in line. Pump, relay and regulator are all original, fuel filter is changed regularly; you don't get to 254k without doing the maintenance...
Thanks in advance,