1991 318is, well maintained. Started one night and drive into the garage. Went to start next morning and it just cranks... I determined the fuel pump was not getting power.
Replaced fuel pump relay. Still no power at fuel pump.
Disconnected fuel line after fuel filter and ran 12 volts to the fuel pump. Pump shot a ton of fuel out the line. Reconnected fuel line and tried to start car with 12 volts directly to the fuel pump. Would not start, just cranks.
I have tested the fuel pump ground and it is perfect. Pulled the fuel pump relay. The terminals the relay plugs into get 12 volts power. I can put a jumper wire between terminals 30 and 85 (if I remember right), and the fuel pump will have constant power. This tells me the wiring is good. Tried to start again and no go.
Pulled a spark plug out and did a spark test. Spark was very strong and a lot of it. This tells me the CPS is good.
So I have fuel... spark... and obviously air.
Using the gas pedal pumping method, my car is throwing only one code. 1215 which is the air flow meter.
Plug into the AFM has 5.4 volts (within spec) and the ohm resistance when you move the wing flap increases with the flap movement so it tells me this is working fine. Regardless, the AFM should not prevent my fuel pump from getting power, correct?
Looking at the fuel pump wiring diagram in my Chiltons manual it goes like this:
Battery ---> engine computer in the glove box ---> main relay ---> and from there one wire splits to the fuel pump relay and the O2 sensor. So I thought the O2 sensor may be grounding out and robbing power from the fuel pump relay. I tested the grounds in my fuse panel and they are good. So there goes that idea... and is it possible for the O2 sensor to even cause these problems?
All the fuses in my fuse box are good. I even replaced #18 (fuel pump fuse) just in case. Checked w/ multimeter and have power.
So the car sits dead in my garage and I am totally stumped.
IDEAS???? And can someone tell me the exact location of the O2 sensor relay??
Replaced fuel pump relay. Still no power at fuel pump.
Disconnected fuel line after fuel filter and ran 12 volts to the fuel pump. Pump shot a ton of fuel out the line. Reconnected fuel line and tried to start car with 12 volts directly to the fuel pump. Would not start, just cranks.
I have tested the fuel pump ground and it is perfect. Pulled the fuel pump relay. The terminals the relay plugs into get 12 volts power. I can put a jumper wire between terminals 30 and 85 (if I remember right), and the fuel pump will have constant power. This tells me the wiring is good. Tried to start again and no go.
Pulled a spark plug out and did a spark test. Spark was very strong and a lot of it. This tells me the CPS is good.
So I have fuel... spark... and obviously air.
Using the gas pedal pumping method, my car is throwing only one code. 1215 which is the air flow meter.
Plug into the AFM has 5.4 volts (within spec) and the ohm resistance when you move the wing flap increases with the flap movement so it tells me this is working fine. Regardless, the AFM should not prevent my fuel pump from getting power, correct?
Looking at the fuel pump wiring diagram in my Chiltons manual it goes like this:
Battery ---> engine computer in the glove box ---> main relay ---> and from there one wire splits to the fuel pump relay and the O2 sensor. So I thought the O2 sensor may be grounding out and robbing power from the fuel pump relay. I tested the grounds in my fuse panel and they are good. So there goes that idea... and is it possible for the O2 sensor to even cause these problems?
All the fuses in my fuse box are good. I even replaced #18 (fuel pump fuse) just in case. Checked w/ multimeter and have power.
So the car sits dead in my garage and I am totally stumped.
IDEAS???? And can someone tell me the exact location of the O2 sensor relay??
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