F150 4.2 1997
#1
#2
Are you saying it continues to run, dieseling? If so, I would put two bottles of Gumout with PEA in the gas for the next several tanks of gas to see if it cleans up the combustion chambers and eliminates the dieseling.
How fast is it idling when you turn it off? If the idle speed is too fast this will contribute to dieseling.
How fast is it idling when you turn it off? If the idle speed is too fast this will contribute to dieseling.
#3
#4
Check your intake manifold gasket. You could be trying to burn coolant.
Check your coolant levels and do a radiator pressure leak down test.
Might not also hurt to do a compression check on all cylinders and report back your findings.
These tools are readily available for rental at most auto parts stores.
Check your coolant levels and do a radiator pressure leak down test.
Might not also hurt to do a compression check on all cylinders and report back your findings.
These tools are readily available for rental at most auto parts stores.
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#5
Johnathan - welcome to the forum. I've moved your thread to a more appropriate subforum.
I think Roadie has given you good advice. What you are describing sounds like "dieseling" to me too. You likely have a buildup of carbon in the engine that stays hot after you turn the ignition off. This carbon ignites gasoline that continues to be delivered to the engine as long as it is turning over. But, the burning doesn't occur at the right time, so you will hear, and possibly feel, an uneven knocking sound for a few seconds after shutting things down.
Getting rid of the carbon and/or lowering the idle speed will help prevent this.
- Jack
I think Roadie has given you good advice. What you are describing sounds like "dieseling" to me too. You likely have a buildup of carbon in the engine that stays hot after you turn the ignition off. This carbon ignites gasoline that continues to be delivered to the engine as long as it is turning over. But, the burning doesn't occur at the right time, so you will hear, and possibly feel, an uneven knocking sound for a few seconds after shutting things down.
Getting rid of the carbon and/or lowering the idle speed will help prevent this.
- Jack
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#6
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#7
Basically when I park and turn off the truck the knocking sounds starts it only happens when it's off I don't hear the knocking sound when the truck in running
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#8
Johnathan - welcome to the forum. I've moved your thread to a more appropriate subforum.
I think Roadie has given you good advice. What you are describing sounds like "dieseling" to me too. You likely have a buildup of carbon in the engine that stays hot after you turn the ignition off. This carbon ignites gasoline that continues to be delivered to the engine as long as it is turning over. But, the burning doesn't occur at the right time, so you will hear, and possibly feel, an uneven knocking sound for a few seconds after shutting things down.
Getting rid of the carbon and/or lowering the idle speed will help prevent this.
- Jack
I think Roadie has given you good advice. What you are describing sounds like "dieseling" to me too. You likely have a buildup of carbon in the engine that stays hot after you turn the ignition off. This carbon ignites gasoline that continues to be delivered to the engine as long as it is turning over. But, the burning doesn't occur at the right time, so you will hear, and possibly feel, an uneven knocking sound for a few seconds after shutting things down.
Getting rid of the carbon and/or lowering the idle speed will help prevent this.
- Jack
#9
Check your intake manifold gasket. You could be trying to burn coolant.
Check your coolant levels and do a radiator pressure leak down test.
Might not also hurt to do a compression check on all cylinders and report back your findings.
These tools are readily available for rental at most auto parts stores.
Check your coolant levels and do a radiator pressure leak down test.
Might not also hurt to do a compression check on all cylinders and report back your findings.
These tools are readily available for rental at most auto parts stores.
#10
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#11
knock for like a minute or two
#12
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#14
Last edited by Johnathan Moody; 03-21-2020 at 03:44 PM.