1997 F150, 4.6 engine problems
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1997 F150, 4.6 engine problems
I have a problem nobody can figure out. My check engine light is on. Took it to Advance to have it scanned; came backwith Code 1226, Brake warning light ground short ( not concerned that at this time); Code P1285, cylinder head over temperature; and P1299, engine overheating (this repeated 4 times). Now for the symptoms: Truck start and runs good, except with engine light on, runs about 4 miles, then the temperature gauge goes all way up, oil light come on (But oil pressure gauge is OK), Have loss power, and heater has no heat. I shut key off, restart, runs perfect, gauges OK, heater OK. Anybody had these problems?
Lead Driver
Joined: Sep 2006
Posts: 7,907
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This is a neat example of not understanding the codes.
Codes 1285 and 1299 are telling you the computer is going into 'Limp Mode' from a bad head gasket, low coolant or what ever the reason is cylinder pressure is leaking into and heating the coolant causing the overheating condition.
Hint, the heater can also be affected since it is in the cooling system and coolant may have already been lost.
There is no mystery when things are understood.
Get a cooling system check for exhaust gas in coolant to verify, then which bank the issue is on, then what you want to do about it.
A way to find which cylinder is to use an Infrared heat gun on the exhaust ports of the exhaust manifold looking for the coolest one .
A spark plug tip check may reveal the cylinder.
Unless you get a well experienced clerk, their understanding is not very deep.
The reason you see the condition change after shutting the engine off then restarting is you 'reset' the condition as well as the engine cools a bit.
Good luck.
.
Codes 1285 and 1299 are telling you the computer is going into 'Limp Mode' from a bad head gasket, low coolant or what ever the reason is cylinder pressure is leaking into and heating the coolant causing the overheating condition.
Hint, the heater can also be affected since it is in the cooling system and coolant may have already been lost.
There is no mystery when things are understood.
Get a cooling system check for exhaust gas in coolant to verify, then which bank the issue is on, then what you want to do about it.
A way to find which cylinder is to use an Infrared heat gun on the exhaust ports of the exhaust manifold looking for the coolest one .
A spark plug tip check may reveal the cylinder.
Unless you get a well experienced clerk, their understanding is not very deep.
The reason you see the condition change after shutting the engine off then restarting is you 'reset' the condition as well as the engine cools a bit.
Good luck.
.
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
You can still have an issue with the CHT sensor circuit.
If it tells the computer the conditions for limp mode, even falsely, you will see the results you see.
Under these conditions the computer intentionally rotates misfiring cylinders by shutting off the injectors.
This is to pass air only in an attempt to cool the motor from heat damage.
You involved the cooling system in your description so I trusted it as fact.
Otherwise you can have the above as a cause.
Shutting off and restarting resets the situation in program.
I understand the motor won't cool that fast.
Good luck.
If it tells the computer the conditions for limp mode, even falsely, you will see the results you see.
Under these conditions the computer intentionally rotates misfiring cylinders by shutting off the injectors.
This is to pass air only in an attempt to cool the motor from heat damage.
You involved the cooling system in your description so I trusted it as fact.
Otherwise you can have the above as a cause.
Shutting off and restarting resets the situation in program.
I understand the motor won't cool that fast.
Good luck.
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