fuel pump 99 discoII help please
#1
09-27-2011, 03:25 PM
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fuel pump 99 discoII help please
okay, hubby ran my disco out of gas for no apparent reason other than his head was up his a**...and we have had a landslide of issues since.
put gas in, reset inertia switch- started and drove home at 1/4 tank. Later that day running errands it dies. Battery will not hold charge - tow to house.
searched forums, replaced fuel pump relay, charged battery, starts! Drives 3 houses down, dies.
Replace battery, starts drives 3 houses or so dies.
Checked all fuses, thinking now its a fuel pump.
Any help or experience with these issues is greatly appreciated. I have searched the forums for a few hours and found as much as I could so decided to start my own thread. Also, can anyone please tell me how to access the fuel pump via the cargo area? TIA!
put gas in, reset inertia switch- started and drove home at 1/4 tank. Later that day running errands it dies. Battery will not hold charge - tow to house.
searched forums, replaced fuel pump relay, charged battery, starts! Drives 3 houses down, dies.
Replace battery, starts drives 3 houses or so dies.
Checked all fuses, thinking now its a fuel pump.
Any help or experience with these issues is greatly appreciated. I have searched the forums for a few hours and found as much as I could so decided to start my own thread. Also, can anyone please tell me how to access the fuel pump via the cargo area? TIA!
#3
09-27-2011, 03:42 PM
Super Moderator
1. Cargo rug/mat comes up, fuel pump assembly under plate below. Download the RAVE tech manual if you don't have it, free, below.
2. You should get a voltmeter so you can check to be sure battery is being charged (13.8 - 14.2 volts when engine running). WIll also need voltmeter to check wiring at fuel pump. BAttery not being charged can die quickly and fuel pump stops. Would look at this carefully and eliminate alternator as a problem before tearing into fuel pump.
3. Fuel pump has fuel filter built in to the assembly, and the whole thing is pricey. But pump alone is like $50.
4. Sensor is a definite possibility. Should also be eliminated before fuel pump.
2. You should get a voltmeter so you can check to be sure battery is being charged (13.8 - 14.2 volts when engine running). WIll also need voltmeter to check wiring at fuel pump. BAttery not being charged can die quickly and fuel pump stops. Would look at this carefully and eliminate alternator as a problem before tearing into fuel pump.
3. Fuel pump has fuel filter built in to the assembly, and the whole thing is pricey. But pump alone is like $50.
4. Sensor is a definite possibility. Should also be eliminated before fuel pump.
#4
09-27-2011, 04:04 PM
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#5
09-27-2011, 08:29 PM
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My concern was battery won't hold charge, if that is no good, fuel pump and lots of other things won't work. Bad alternator, dead cell in battery, etc. Worth testing.
From the RAVE tech manual about the crank position sensor (see last part in red) :
generated. In this instance the MIL lamp will remain illuminated and the tachometer will fail to read.
From the RAVE tech manual about the crank position sensor (see last part in red) :
The CKP sensor is located towards the rear of the engine below cylinder number 7, with its tip adjacent to the outer
circumference of the flywheel. The CKP sensor is the most important sensor on the vehicle and without its signal the
engine will not run. The signal produced by the CKP sensor allows the ECM to determine crankshaft angle and speed
of rotation. The ECM uses this information to calculate ignition timing and fuel injection timing.
The CKP sensor works as a variable reluctance sensor. It uses an electromagnet and a reluctor ring to generate a
signal. As the reluctor ring passes the tip of the CKP sensor the magnetic field produced by the sensor is cut and then
re-instated. The ECM measures the signal as an ac voltage.
The output voltage varies in proportion to engine speed. The reluctor ring has a set tooth pattern, 60 teeth are spaced
at 6
circumference of the flywheel. The CKP sensor is the most important sensor on the vehicle and without its signal the
engine will not run. The signal produced by the CKP sensor allows the ECM to determine crankshaft angle and speed
of rotation. The ECM uses this information to calculate ignition timing and fuel injection timing.
The CKP sensor works as a variable reluctance sensor. It uses an electromagnet and a reluctor ring to generate a
signal. As the reluctor ring passes the tip of the CKP sensor the magnetic field produced by the sensor is cut and then
re-instated. The ECM measures the signal as an ac voltage.
The output voltage varies in proportion to engine speed. The reluctor ring has a set tooth pattern, 60 teeth are spaced
at 6
° intervals and are 3° wide, two teeth are removed to provide a reference mark at 60° BTDC for number 1 cylinder.
There is no back up strategy or limp home facility if this sensor fails, the engine does not run.
There is no back up strategy or limp home facility if this sensor fails, the engine does not run.
Input/Output
Because of the nature of its operation the CKP sensor does not require any electrical input source. The CKP sensor
is a 3 pin variable reluctance sensor generating its own electrical output. The 2 output sources from the sensor are
earthed via pin 46 of connector C0636 of the ECM and sensor output is via pin 32 of connector C0636 of the ECM.
This output is in the form of an ac voltage waveform. The 3rd pin is used by the ECM as an earth screen, this screen
protects the integrity of the CKP sensor signal to ensure that outside electrical interference is eliminated, it is
controlled via pin 45 of connector C0636 of the ECM. The ac voltage generated from the CKP sensor is relative to
engine speed.is a 3 pin variable reluctance sensor generating its own electrical output. The 2 output sources from the sensor are
earthed via pin 46 of connector C0636 of the ECM and sensor output is via pin 32 of connector C0636 of the ECM.
This output is in the form of an ac voltage waveform. The 3rd pin is used by the ECM as an earth screen, this screen
protects the integrity of the CKP sensor signal to ensure that outside electrical interference is eliminated, it is
controlled via pin 45 of connector C0636 of the ECM. The ac voltage generated from the CKP sensor is relative to
The above readings are dependent upon correct air gap between the tip of the CKP sensor and the passing teeth of
the reluctor ring. The correct air gap between the tip of the CKP sensor and the passing teeth of the reluctor ring can
be set by the correct fitting of a spacer as follows:
the reluctor ring. The correct air gap between the tip of the CKP sensor and the passing teeth of the reluctor ring can
be set by the correct fitting of a spacer as follows:
l
9.2 mm spacer for vehicles with manual gearbox fitted.
l
18 mm spacer for vehicles with automatic gearbox fitted.
It is vital that the correct air gap is maintained, if the air gap becomes too wide the CKP signal becomes too weak,
causing possible engine misfires to occur.
The CKP sensor can fail the following ways or supply incorrect signal:
It is vital that the correct air gap is maintained, if the air gap becomes too wide the CKP signal becomes too weak,
causing possible engine misfires to occur.
The CKP sensor can fail the following ways or supply incorrect signal:
l
Sensor assembly loose.
l
Incorrect spacer fitted.
l
Sensor open circuit.
l
Sensor short circuit.
l
Incorrect fitting and integrity of the sensor.
l
Water ingress at sensor connector
l
ECM unable to detect the software reference point.
l
Ferrous contamination of crank sensor pin/reluctor
In the event of a CKP sensor signal failure any of the following symptoms may be observed:
In the event of a CKP sensor signal failure any of the following symptoms may be observed:
l
Engine cranks but fails to start.
l
MIL remains on at all times.
l
Engine misfires (CKP sensor incorrectly fitted).
l
Engine runs roughly or even stalls (CKP sensor incorrectly fitted).
l
Tachometer fails to work.
l
Flywheel adaption reset – ferrous contamination
If the CKP sensor fails while the engine is running the engine will suddenly stall, this is because the CKP sensor has
no backup strategy. If this happens the ECM will produce a fault code that it can store in its memory. If the engine is
not running when the CKP sensor fails, the vehicle will crank but will be unlikely to start, and no fault code will be
If the CKP sensor fails while the engine is running the engine will suddenly stall, this is because the CKP sensor has
no backup strategy. If this happens the ECM will produce a fault code that it can store in its memory. If the engine is
not running when the CKP sensor fails, the vehicle will crank but will be unlikely to start, and no fault code will be
generated. In this instance the MIL lamp will remain illuminated and the tachometer will fail to read.
#6
09-27-2011, 08:41 PM
To know if it is a bad crank sensor do this when it happens, remove a spark plug, reattach the spark plug wire.
Have someone try and start the engine while another person watches for a spark from the spark plug.
DO NOT hold onto the spark plug while doing this.
If there is no spark then it is a bad crank position sensor.
There is a write up on how to replace it in the write up section.
If you have spark then it is the fuel pump.
Have someone try and start the engine while another person watches for a spark from the spark plug.
DO NOT hold onto the spark plug while doing this.
If there is no spark then it is a bad crank position sensor.
There is a write up on how to replace it in the write up section.
If you have spark then it is the fuel pump.
#7
09-28-2011, 07:58 AM
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