Gerald Thomas
G-Force
02 liberty sport v6. Is it really vapor lock or the fuel temp sending unit
Vapor lock, really!
- Thread starter Gerald Thomas
- Start date
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first&lastKJ
Full Access Member
What is it doing?
Our 02 would turn over but not restart immediately after shutting the engine off. Let it sit for 20 minutes it would start right up and run fine. It was the camshaft position sensor.
Our 02 would turn over but not restart immediately after shutting the engine off. Let it sit for 20 minutes it would start right up and run fine. It was the camshaft position sensor.
Last edited:
Gerald Thomas
G-Force
My 02 starts right up when it's cold, but takes 3 cranks to start when it gets up to operating temp. Was thinking it was the fuel temperature sensing unit read somewhere that when it goes out thinks it is 35 below fuel-air mixture is off . Read one fourm that said it was vapor lock. No codes are showing up. How do you get your diagnostic that would be great
Billwill
Full Access Member
Cam Sensor and Crank Sensors can fail when they get hot.
You can heat them up on a cold Jeep with a Hairdryer and see if the engine fails to start but then starts once the Jeep has cooled down.
Best to use OEM sensors.
You ideally need to draw Error Codes with a Code Reader.
On the early KJs you can use the "key" trick to pull codes out with some limitations.
Without starting the engine rapidly turn the ignition ON/OFF 3 times.
After the 3rd ON action leave the ignition ON.
The Odometer Display should show stored codes in sequence from the oldest....which may no longer be relevant..to the newest codes.
Look up the newest codes in the 2002 Jeep KJ Service Manual below.
The codes cannot be erased using this method and sometimes the last two digits can be swapped over which can confuse!
I use this method plenty times on my 2002 Export CRD but strangely for the Export KJ this key action has to be done rapidly 4 times! It is pretty impossible to get a Code Reader for the 2002 models as they use a PCI protocol which most Code Readers cannot read...need to go to a Dealer or use the Key trick!
www.colorado4wheel.com/manuals/Jeep/KJ/
You can heat them up on a cold Jeep with a Hairdryer and see if the engine fails to start but then starts once the Jeep has cooled down.
Best to use OEM sensors.
You ideally need to draw Error Codes with a Code Reader.
On the early KJs you can use the "key" trick to pull codes out with some limitations.
Without starting the engine rapidly turn the ignition ON/OFF 3 times.
After the 3rd ON action leave the ignition ON.
The Odometer Display should show stored codes in sequence from the oldest....which may no longer be relevant..to the newest codes.
Look up the newest codes in the 2002 Jeep KJ Service Manual below.
The codes cannot be erased using this method and sometimes the last two digits can be swapped over which can confuse!
I use this method plenty times on my 2002 Export CRD but strangely for the Export KJ this key action has to be done rapidly 4 times! It is pretty impossible to get a Code Reader for the 2002 models as they use a PCI protocol which most Code Readers cannot read...need to go to a Dealer or use the Key trick!
www.colorado4wheel.com/manuals/Jeep/KJ/
Gerald Thomas
G-Force
Thank you IL try that. Sounds more sence able than vapor lock. Did the same thing happen to youCam Sensor and Crank Sensors can fail when they get hot.
You can heat them up on a cold Jeep with a Hairdryer and see if the engine fails to start but then starts once the Jeep has cooled down.
Best to use OEM sensors.
You ideally need to draw Error Codes with a Code Reader.
On the early KJs you can use the "key" trick to pull codes out with some limitations.
Without starting the engine rapidly turn the ignition ON/OFF 3 times.
After the 3rd ON action leave the ignition ON.
The Odometer Display should show stored codes in sequence from the oldest....which may no longer be relevant..to the newest codes.
Look up the newest codes in the 2002 Jeep KJ Service Manual below.
The codes cannot be erased using this method and sometimes the last two digits can be swapped over which can confuse!
I use this method plenty times on my 2002 Export CRD but strangely for the Export KJ this key action has to be done rapidly 4 times! It is pretty impossible to get a Code Reader for the 2002 models as they use a PCI protocol which most Code Readers cannot read...need to go to a Dealer or use the Key trick!
www.colorado4wheel.com/manuals/Jeep/KJ/
Gerald Thomas
G-Force
But mine starts right back up after 2 to three cranks and runs great
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