rlnilson
New Member
- Joined
- March 12, 2017
- Messages
- 5
- Reaction score
- 0
- City, State
- Utah
- Year, Model & Trim Level
- 2005, Explorer XLT
2005 Ford Explorer XLT. 4.0 V6 198,000mi
Every so often my explorer has a strange running issue. 2/3 of the time i experience this issue It starts, then dies within 5-30 seconds. (usually when reversing out of my driveway) the other 1/3 it won't start at all but has the same symptoms as after running 5-30 seconds. it has never quit while driving forward, or after it has run for over 30 seconds.
The crazy part is it will ALWAYS start if I wait 2-6 hours. As if it had no issues. It runs well every other time aside from this odd crank/no start issue.
It usually has this issue after sitting at least 4hrs or overnight. It has not happened after the engine is warmed up, it's always cold. The ambient temp while this has occurred has been between 20 and 65 degrees. The theft detection system is not tripped. The red light on the dash is solid when key is on, then turns off after i try to crank. The light does not flash. If I try the other key while having this issue it changes nothing. The light acts exactly the same when the issue goes away.
No codes, no abnormal issues sent to my scan tool as far as I can see. (basic $90 unit. Not fancy dealer level one).
It always cranks without starting, sounds like it's not getting fuel. Occasionally it sputters, but very little, and very rarely. Alternator is less than 2years old, and outputs 14volts when running. battery is less than a year old, and maintains 12.5 volts when off.
When it is malfunctioning i have tested the following:
The fuel pump relay tests fine, I swapped it with another one inside, no change. I jumped the relay switch side to bypass the relay, no change.The fuel pump is also receiving 12v, and I hear it running for a moment after I turn on the key.
It has spark. I tested with an inline spark tester. It sparks consistently and strongly.
The fuel rail pressure sensor shows 35-40 psi key on engine off, and up to 60psi when cranking. (I believe the fuel rail pressure sensor is working because if I disconnect the fuel pump relay, and release pressure from the rail schrader the frp sensor shows approx 0.35ish psi pressure. I reconnect the fuel pump relay, try to start, check the pressure again with my scan tool, it's right back up to 35-40psi, still no start.
I have not tested the injectors individually, i know they work when it ALWAYS starts running again after 2-6 hrs. Besides, they wouldn't all malfunction at once. I know the Crank and Cam position sensors aren't malfunctioning consistently because it will restart. (also, I'm getting spark consistently, which means the sensors are functioning, and I am getting no codes. Am i correct in this understanding?)
I have not tested to see if the injectors are receiving signal from the ECU. I have not had the chance because it comes back to life after a while and works fine for days or weeks. I have not tested or replaced cam or crank sensors. I have not had the chance to test fuel pressure at the rail because so far I've trusted the onboard sensor. Next time I have this issue I will test it with my manual gauge just to ensure pressure is sufficient.
My biggest suspect is the fuel pump working inconsistently or not receiving sufficient power. (but the sensor shows sufficient pressure... so that doesn't make sense) I could hard wire 12v to the fuel pump to ensure it's getting enough current. However, since this vehicle has no fuel return line I would be delivering too much pressure to the fuel rail, so I have not tried that yet, pending some advice on what to try next.
Any ideas or suggestions what else I can test? Really challenging to test because it is so inconsistent.
Every so often my explorer has a strange running issue. 2/3 of the time i experience this issue It starts, then dies within 5-30 seconds. (usually when reversing out of my driveway) the other 1/3 it won't start at all but has the same symptoms as after running 5-30 seconds. it has never quit while driving forward, or after it has run for over 30 seconds.
The crazy part is it will ALWAYS start if I wait 2-6 hours. As if it had no issues. It runs well every other time aside from this odd crank/no start issue.
It usually has this issue after sitting at least 4hrs or overnight. It has not happened after the engine is warmed up, it's always cold. The ambient temp while this has occurred has been between 20 and 65 degrees. The theft detection system is not tripped. The red light on the dash is solid when key is on, then turns off after i try to crank. The light does not flash. If I try the other key while having this issue it changes nothing. The light acts exactly the same when the issue goes away.
No codes, no abnormal issues sent to my scan tool as far as I can see. (basic $90 unit. Not fancy dealer level one).
It always cranks without starting, sounds like it's not getting fuel. Occasionally it sputters, but very little, and very rarely. Alternator is less than 2years old, and outputs 14volts when running. battery is less than a year old, and maintains 12.5 volts when off.
When it is malfunctioning i have tested the following:
The fuel pump relay tests fine, I swapped it with another one inside, no change. I jumped the relay switch side to bypass the relay, no change.The fuel pump is also receiving 12v, and I hear it running for a moment after I turn on the key.
It has spark. I tested with an inline spark tester. It sparks consistently and strongly.
The fuel rail pressure sensor shows 35-40 psi key on engine off, and up to 60psi when cranking. (I believe the fuel rail pressure sensor is working because if I disconnect the fuel pump relay, and release pressure from the rail schrader the frp sensor shows approx 0.35ish psi pressure. I reconnect the fuel pump relay, try to start, check the pressure again with my scan tool, it's right back up to 35-40psi, still no start.
I have not tested the injectors individually, i know they work when it ALWAYS starts running again after 2-6 hrs. Besides, they wouldn't all malfunction at once. I know the Crank and Cam position sensors aren't malfunctioning consistently because it will restart. (also, I'm getting spark consistently, which means the sensors are functioning, and I am getting no codes. Am i correct in this understanding?)
I have not tested to see if the injectors are receiving signal from the ECU. I have not had the chance because it comes back to life after a while and works fine for days or weeks. I have not tested or replaced cam or crank sensors. I have not had the chance to test fuel pressure at the rail because so far I've trusted the onboard sensor. Next time I have this issue I will test it with my manual gauge just to ensure pressure is sufficient.
My biggest suspect is the fuel pump working inconsistently or not receiving sufficient power. (but the sensor shows sufficient pressure... so that doesn't make sense) I could hard wire 12v to the fuel pump to ensure it's getting enough current. However, since this vehicle has no fuel return line I would be delivering too much pressure to the fuel rail, so I have not tried that yet, pending some advice on what to try next.
Any ideas or suggestions what else I can test? Really challenging to test because it is so inconsistent.
