4.0 L long crank time before start
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Mountain Pass
Joined: Apr 2012
Posts: 196
Likes: 1
4.0 L long crank time before start
So my 2002 ford explorer with the 4.0 L V6, has been cranking along time before it starts. I thought i had this figured out already, i put a brand new fuel pump in it from the ford dealer. That seemed to help, but the problem came back.
Especially when it is cold, it cranks a lot longer than normal to start. and when it does start RMPS go way up briefly and come back down.
Seems to only act up when its cold out, say 35 degrees and lower.
So the remote start wont work because it only cranks for a few seconds and then stops. it tries this three times and it gives up. i go out there to start it and cranks for 10 seconds it seems like, sometimes i have to feather the fuel pedal.
What do you guys think?
Especially when it is cold, it cranks a lot longer than normal to start. and when it does start RMPS go way up briefly and come back down.
Seems to only act up when its cold out, say 35 degrees and lower.
So the remote start wont work because it only cranks for a few seconds and then stops. it tries this three times and it gives up. i go out there to start it and cranks for 10 seconds it seems like, sometimes i have to feather the fuel pedal.
What do you guys think?
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Mountain Pass
Joined: Apr 2012
Posts: 196
Likes: 1
This is what i am thinking.
We can rule the fuel pump out, its a new ford pump, this has the check valve built into it.
New fuel filter, has three hoses going to it, one for return fuel.
Fuel pressure regulator, doesn't appear to be leaking, you can feel the vacuum pulsing.
Possible fuel relay acts up when its cold?
Fuel pressure sensor acts up when its cold?
The only thing left would be an stickey injector?
We can rule the fuel pump out, its a new ford pump, this has the check valve built into it.
New fuel filter, has three hoses going to it, one for return fuel.
Fuel pressure regulator, doesn't appear to be leaking, you can feel the vacuum pulsing.
Possible fuel relay acts up when its cold?
Fuel pressure sensor acts up when its cold?
The only thing left would be an stickey injector?
Thread Starter
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Mountain Pass
Joined: Apr 2012
Posts: 196
Likes: 1
Ok I see what your thinking...if the temp sensor isn't working the computer doesnt know its cold and its trying to start like its warm out. Lots of variables change when it cold. And this is why it only happens when it's freezing out. So I would have to test the sensor when it's cold. If it tests bad, this could be the problem.
Logistics Pro
Joined: Jun 2009
Posts: 4,808
Likes: 83
From: Cedar Rapids, IA
A couple of other things to check - 1) spark plugs and wires (unless 2002 was already CoP on that engine), and 2) it sounds like you have an aftermarket remote starter installed. Some installers had the "bright" idea to install the starter disable relay in series with the fuel pump wiring to kill the fuel pump in the event of an unauthorized start attempt. You can guess what happens when that relay gets flaky. You might want to confirm that when the truck doesn't want to start, the fuel pump is getting power.
-Rod
-Rod
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Mountain Pass
Joined: Apr 2012
Posts: 196
Likes: 1
Hi Rod, i see your point.
Tricky part is, i have never had it not start, it just takes a few more seconds until it does start.
It has new spark plugs and wires already (no coil on plug)
I think i should just replace the relay.
I think i am going to change the ECT sensor too. To replace the sensor you have to remove the thermostat and its probably due for a new thermostat anyway.
So i think the cheapest quickest route is, new fuel pump relay, thermostat and ect sensor.
What do you guys think im on the right track to getting this extended crank time fixed?
By the time i get this figured out the cold weather will be gone and it wont be an issue....
Tricky part is, i have never had it not start, it just takes a few more seconds until it does start.
It has new spark plugs and wires already (no coil on plug)
I think i should just replace the relay.
I think i am going to change the ECT sensor too. To replace the sensor you have to remove the thermostat and its probably due for a new thermostat anyway.
So i think the cheapest quickest route is, new fuel pump relay, thermostat and ect sensor.
What do you guys think im on the right track to getting this extended crank time fixed?
By the time i get this figured out the cold weather will be gone and it wont be an issue....
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Postmaster
Joined: Oct 2003
Posts: 4,516
Likes: 1
From: SoCal
Another thing you can try is to cycle the key on for 2 seconds then off. Repeat 5 times and see how it starts.
To test the ECT remove the 2 wire connector & connect your ohm meter, if you dont live in Siberia or Chicago it should read around 40 to 50,000 ohms when the engine is cold.
To test the ECT remove the 2 wire connector & connect your ohm meter, if you dont live in Siberia or Chicago it should read around 40 to 50,000 ohms when the engine is cold.
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