Lower LTFT during hot days, a MAF problem?
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Joined: Oct 2003
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From: Zurich - Switzerland
Lower LTFT during hot days, a MAF problem? Those days we have 85 - 90 F.
While cruising the LTFT's are +2 / -2, but as soon I drive in traffic or uphill they get low and reach values around -10%.
In the night the LTFT's stay pretty close to 0%.
Is it possible that when the engine bay gets very hot the MAF starts having problems? Or is there any other component that is temperature sensitive?
The IAT shows normal values, both banks have the same LTFT values, so it's not something about injectors of oxygen sensors.
MAP is OK, coolant temperature is between 205 and 220 F (nothing exceptional).
I don't think it's a mechanical problem, because when I let the car cool down for a couple of hours LTFT's get back to normal values (+2 / -2).
It's not limp mode: the actual timing is the same as the high octane values.
Any idea?
Thanks!!
Stefano
While cruising the LTFT's are +2 / -2, but as soon I drive in traffic or uphill they get low and reach values around -10%.
In the night the LTFT's stay pretty close to 0%.
Is it possible that when the engine bay gets very hot the MAF starts having problems? Or is there any other component that is temperature sensitive?
The IAT shows normal values, both banks have the same LTFT values, so it's not something about injectors of oxygen sensors.
MAP is OK, coolant temperature is between 205 and 220 F (nothing exceptional).
I don't think it's a mechanical problem, because when I let the car cool down for a couple of hours LTFT's get back to normal values (+2 / -2).
It's not limp mode: the actual timing is the same as the high octane values.
Any idea?
Thanks!!
Stefano
Originally Posted by tici
Those days we have 85 - 90 F.
While cruising the LTFT's are +2 / -2, but as soon I drive in traffic or uphill they get low and reach values around -10%.
In the night the LTFT's stay pretty close to 0%.
Is it possible that when the engine bay gets very hot the MAF starts having problems? Or is there any other component that is temperature sensitive?
The IAT shows normal values, both banks have the same LTFT values, so it's not something about injectors of oxygen sensors.
MAP is OK, coolant temperature is between 205 and 220 F (nothing exceptional).
I don't think it's a mechanical problem, because when I let the car cool down for a couple of hours LTFT's get back to normal values (+2 / -2).
It's not limp mode: the actual timing is the same as the high octane values.
Any idea?
Thanks!!
Stefano
While cruising the LTFT's are +2 / -2, but as soon I drive in traffic or uphill they get low and reach values around -10%.
In the night the LTFT's stay pretty close to 0%.
Is it possible that when the engine bay gets very hot the MAF starts having problems? Or is there any other component that is temperature sensitive?
The IAT shows normal values, both banks have the same LTFT values, so it's not something about injectors of oxygen sensors.
MAP is OK, coolant temperature is between 205 and 220 F (nothing exceptional).
I don't think it's a mechanical problem, because when I let the car cool down for a couple of hours LTFT's get back to normal values (+2 / -2).
It's not limp mode: the actual timing is the same as the high octane values.
Any idea?
Thanks!!
Stefano
