Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
2002 F350 Super Duty High Idle / intermittent misfire NO DTCs
This truck has been throwing me for a loop. Seems like I'll correct one or two issues, just to find three more.
So, to begin:
Truck is idling high, typically around 1000 rpm, sometimes idle will surge as high as 1500 rpm.
When I initially scanned it, the only two DTCs that came up were one for high cylinder head temperature sensor voltage, and another for readiness monitors not being run.
Did a visual inspection, what do ya know...someone disconnected the CHT sensor.
Plugged it back in, cleared the code and it didn't pop back up.
Didn't solve drive-ability concern, So I pull up live data for the PCM.
LTFT are both +12-16 on both banks.
My MAF sensor is only reading 12 g/s at WOT
and my CHT sensor is stuck at 174 degrees F.
I've got 5V @ CHT sensor, decided to change the sensor.
Changed out MAF sensor because I happened to have one laying around, but vRef for my MAF is only 4.62V.
Is that skewing my sensor data?
It looks like the CHT and MAF both get vRef from different lines, those are the only two sensors that I see with bad readings.
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