Engine Still in Fail Safe Mode
#21
Scott,
Could that possibly be P0172 and P0175? Those are rich system faults. Overly rich conditions can be caused by fuel pressure regulator failure [fuel pressure too high], Mass Air Flow Sensor over reporting incoming air, or possibly a purge system fault causing fuel/vapor to be drawn in straight from the fuel tank.
If the incoming air is reported as too high, the ECM fuels more to match that air; the oxygen sensors say "we're runnin' too rich" and the ECM subtracts fuel accordingly. The ECM says, "if I gotta take away fuel, we must be runnin' rich, set the code".
Good luck!
Could that possibly be P0172 and P0175? Those are rich system faults. Overly rich conditions can be caused by fuel pressure regulator failure [fuel pressure too high], Mass Air Flow Sensor over reporting incoming air, or possibly a purge system fault causing fuel/vapor to be drawn in straight from the fuel tank.
If the incoming air is reported as too high, the ECM fuels more to match that air; the oxygen sensors say "we're runnin' too rich" and the ECM subtracts fuel accordingly. The ECM says, "if I gotta take away fuel, we must be runnin' rich, set the code".
Good luck!
Last edited by xjrguy; 01-19-2011 at 04:22 PM.
#22
#23
Scott,
Could that possibly be P0172 and P0175? Those are rich system faults. Overly rich conditions can be caused by fuel pressure regulator failure [fuel pressure too high], Mass Air Flow Sensor over reporting incoming air, or possibly a purge system fault causing fuel/vapor to be drawn in straight from the fuel tank.
If the incoming air is reported as too high, the ECM fuels more to match that air; the oxygen sensors say "we're runnin' too rich" and the ECM subtracts fuel accordingly. The ECM says, "if I gotta take away fuel, we must be runnin' rich, set the code".
Good luck!
Could that possibly be P0172 and P0175? Those are rich system faults. Overly rich conditions can be caused by fuel pressure regulator failure [fuel pressure too high], Mass Air Flow Sensor over reporting incoming air, or possibly a purge system fault causing fuel/vapor to be drawn in straight from the fuel tank.
If the incoming air is reported as too high, the ECM fuels more to match that air; the oxygen sensors say "we're runnin' too rich" and the ECM subtracts fuel accordingly. The ECM says, "if I gotta take away fuel, we must be runnin' rich, set the code".
Good luck!
Thanks, also for the part number on the other post.
#24
My Corvette and various Northstar equipped Ed Dorados ran fine on regular gas. I could never sense a difference at all other than MPG. Interestingly, the decrease in MPG was not enough to offset the increase in $PG at the time...
#25
You are correct in that. However, I have so many ****ling engine management problems with the XK8 that I deceded to run Premium just to remove one variable from the equation. I have to say that the car ran much better - crisper in terms of response - and although the problems didn't go away, they were less frequent.
My Corvette and various Northstar equipped Ed Dorados ran fine on regular gas. I could never sense a difference at all other than MPG. Interestingly, the decrease in MPG was not enough to offset the increase in $PG at the time...
My Corvette and various Northstar equipped Ed Dorados ran fine on regular gas. I could never sense a difference at all other than MPG. Interestingly, the decrease in MPG was not enough to offset the increase in $PG at the time...
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