MAF Diver
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- Posts
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Discovery 2a 2003 V8 4L (Australian)
Symptoms:
(1) Oscillating between only 0V and 1.13V readings in the bank 2 oxygen sensor (bank 1 normal): same behavior when sensor unplugged
(2) Had collected up error codes: P1171, P1174, P0150, P0174
(3) Exhaust sprays out liquid on ignition, quite a lot, then calms down mostly
(4) Exhaust fumes are sharp on the throat, very not pleasent
(5) Feels slightly underpowered, slower response, but not crazy slow
(6) Jolts sideways on ignition
(7) Bank 2 sensor sooty black
(8) Long term fuel trim 25% bank 2 (bank 1 at 2.34%)
(X) Unrelated: there's a coolant leak from the throttle body heater (again...), but bank 1 O2 sensor seems to be unaffected by the water
Photos:
Startup video:
Facts:
- Unfixed vacuum leak on brake booster to inlet manifold (ages ago)
- Unfixed vacuum leak on spring/spindle of throttle position control (ages ago)
- O2 sensor is less than a year old (both replaced at once), Bosch
- Sensor is black and sooty
- One of the connectors (for heating) in both the harness and sensor had wet blue/green gunk in it (my coolant is blue, but no spills nearby)
- Cleaned the harness/ECU connector from the gunk
- Tried an old sensor in its place (should have at least semi-worked), same issue
- Engine looked clean and new new when I had it open last July
Haven't checked:
A) Spark plugs, wires (less than a year old)
B) Bank 1 O2 sensor
C) MAF (less than a year old)
D) Fuel injector o-rings replaced in July
E) Fuel injector cleaning fluid
F) Haven't checked the idle air control valve, but I cleaned it less than a year ago, had a tiny bit of gunk then
What should I eliminate first?
Here we go again...
Symptoms:
(1) Oscillating between only 0V and 1.13V readings in the bank 2 oxygen sensor (bank 1 normal): same behavior when sensor unplugged
(2) Had collected up error codes: P1171, P1174, P0150, P0174
(3) Exhaust sprays out liquid on ignition, quite a lot, then calms down mostly
(4) Exhaust fumes are sharp on the throat, very not pleasent
(5) Feels slightly underpowered, slower response, but not crazy slow
(6) Jolts sideways on ignition
(7) Bank 2 sensor sooty black
(8) Long term fuel trim 25% bank 2 (bank 1 at 2.34%)
(X) Unrelated: there's a coolant leak from the throttle body heater (again...), but bank 1 O2 sensor seems to be unaffected by the water
Photos:
Startup video:
Facts:
- Unfixed vacuum leak on brake booster to inlet manifold (ages ago)
- Unfixed vacuum leak on spring/spindle of throttle position control (ages ago)
- O2 sensor is less than a year old (both replaced at once), Bosch
- Sensor is black and sooty
- One of the connectors (for heating) in both the harness and sensor had wet blue/green gunk in it (my coolant is blue, but no spills nearby)
- Cleaned the harness/ECU connector from the gunk
- Tried an old sensor in its place (should have at least semi-worked), same issue
- Engine looked clean and new new when I had it open last July
Haven't checked:
A) Spark plugs, wires (less than a year old)
B) Bank 1 O2 sensor
C) MAF (less than a year old)
D) Fuel injector o-rings replaced in July
E) Fuel injector cleaning fluid
F) Haven't checked the idle air control valve, but I cleaned it less than a year ago, had a tiny bit of gunk then
What should I eliminate first?
Here we go again...
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