Engine turns over for a few seconds before starting?
#1
Engine turns over for a few seconds before starting?
2001 5.2L
I noticed that my engine would turn over for a few seconds before it started...or maybe I would have to turn the key back and try again before it fired up. The starter sounds great and I have full battery.
I changed the cap/rotor all the plugs and wires...thinking maybe that would help, but it is still the same. The truck runs great and super smooth, but it just takes a bit to start it up.
Anyone know why this might be? I have tried turning the key to "on" to let the fuel pump gain pull pressure for a few seconds before turning the key to start it, doesn't help. The truck does this probably about 7 out of 10 times, and is a bit worse when cold. I don't want to take life off the starter. Anyone with a similar problem?
I noticed that my engine would turn over for a few seconds before it started...or maybe I would have to turn the key back and try again before it fired up. The starter sounds great and I have full battery.
I changed the cap/rotor all the plugs and wires...thinking maybe that would help, but it is still the same. The truck runs great and super smooth, but it just takes a bit to start it up.
Anyone know why this might be? I have tried turning the key to "on" to let the fuel pump gain pull pressure for a few seconds before turning the key to start it, doesn't help. The truck does this probably about 7 out of 10 times, and is a bit worse when cold. I don't want to take life off the starter. Anyone with a similar problem?
#3
Temp when I bought it last week...55-65 Temp today...35-60 (really no difference in performance)
Good question on the battery.... I just bought the truck with 90K miles. The battery is an OEM Mopar battery, but the dates are not circled/etched out on the battery. Don't know when it was installed. Could it be the original on a 2001? I suppose.... Maybe I should start there?
Good question on the battery.... I just bought the truck with 90K miles. The battery is an OEM Mopar battery, but the dates are not circled/etched out on the battery. Don't know when it was installed. Could it be the original on a 2001? I suppose.... Maybe I should start there?
Last edited by Jeffress77; 10-31-2010 at 11:22 PM.
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I agree, it sounds like a fuel pump delivery issue and, without measuring anything, one cannot rule out a fuel pressure issue. I'm staying with a friend of mine who's got a 99 that does this and, I took a reading. Sure enough, it is low thus, why it starts and sometimes it does not - DESPITE turning KEY <ON> to prime the pump.
I highly recommend taking measurements over a period of time to "see" what the fuel pump / delivery system is actually doing vs. just assuming it's ok because, in my experience with fuel delivery systems, often enough, it's a lack of fuel pressure that causes a hard start / no start condition.
EDIT: Even when turning the KEY <ON> event, if the voltage at the FUEL PUMP connector is LOW or, there's a voltage drop anywhere in that CKT, the pump WILL NOT prime the system in ONE KEY ON event thus, requiring multiple attempts to obtain / reach the MIN operating pressure.
<IF> the FUEL PUMP regulator check valve remains OPEN, it will not hold pressure and, after KEY <ON> event, the gas flows directly back into the tank thus, inducing a hard start condition. This is also why it may be hit or miss more so vs. when there's a voltage drop in the CKT.
Now, there's a few other things that will also induce a hard start such as leaking injectors and, in order to find out what the root problem is, testing is required to rule and / or factor out each possible failure mode.
I would start with the pump pressure first. I would run five cold pressure tests on random days to gain stats over time. I would also measure the voltage at the FUEL PUMP during each test to see if there's any correlation. Let's say on one day, the pressure is ~30 PSI, if the voltage at the connector reads <12 volts, well, that's the correlation between the two and, one could safely say that, the low pressure was directly related / induced by a voltage drop at the fuel pump connector or, perhaps, at some other point in the wiring harness and / or CKT respectively.
<IF> the FUEL PUMP / PSI readings measure up (~50 psi), one can factor out the fuel pump as suspect and move on.
CM
I highly recommend taking measurements over a period of time to "see" what the fuel pump / delivery system is actually doing vs. just assuming it's ok because, in my experience with fuel delivery systems, often enough, it's a lack of fuel pressure that causes a hard start / no start condition.
EDIT: Even when turning the KEY <ON> event, if the voltage at the FUEL PUMP connector is LOW or, there's a voltage drop anywhere in that CKT, the pump WILL NOT prime the system in ONE KEY ON event thus, requiring multiple attempts to obtain / reach the MIN operating pressure.
<IF> the FUEL PUMP regulator check valve remains OPEN, it will not hold pressure and, after KEY <ON> event, the gas flows directly back into the tank thus, inducing a hard start condition. This is also why it may be hit or miss more so vs. when there's a voltage drop in the CKT.
Now, there's a few other things that will also induce a hard start such as leaking injectors and, in order to find out what the root problem is, testing is required to rule and / or factor out each possible failure mode.
I would start with the pump pressure first. I would run five cold pressure tests on random days to gain stats over time. I would also measure the voltage at the FUEL PUMP during each test to see if there's any correlation. Let's say on one day, the pressure is ~30 PSI, if the voltage at the connector reads <12 volts, well, that's the correlation between the two and, one could safely say that, the low pressure was directly related / induced by a voltage drop at the fuel pump connector or, perhaps, at some other point in the wiring harness and / or CKT respectively.
<IF> the FUEL PUMP / PSI readings measure up (~50 psi), one can factor out the fuel pump as suspect and move on.
CM
Last edited by cmckenna; 11-01-2010 at 12:53 PM.