Hello Out There, Have An O1 Disco That Will Not Start.no Power At Fuel Pump. Can Cross Over Relay To Get Pump Started But Still Will Not Start. Put Ether To Air Intake And It Will Attempt To Run. Looks Like Ecm Triggers Pump Relay.what Triggers Ecm To Start Relay.have Very Bad Wiring Diagrams From Alldata Need A Microscope To Read Them. Thanks For All Your Help Norm
01 Disco Cranks No Start
- Thread starter NORMRSC1
- Start date
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Any maintenance history prior to this issue?
Check the voltage at the battery.
Try locking/unlocking the drivers door with the key.
Check all the fuses.
Any other recent issues?
Check the voltage at the battery.
Try locking/unlocking the drivers door with the key.
Check all the fuses.
Any other recent issues?
Have Checked All Fuses Inside And Out.battery Voltage Is At 12.5. Have Tried The Key And Button Several Times.also Cleaned Both Battery Terminal. Have Had Vehicle For One Year No Other Issues Except Leaking Valve Covers. Thanks So Much For The Reply
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could be the crank position sensor....
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
generated. In this instance the MIL lamp will remain illuminated and the tachometer will fail to read.
It is vital that the CKP sensor output wires are not reversed (i.e. the connector is fitted incorrectly) as this will cause
a 3 advance in ignition timing. This happens because the ECM uses the falling edge of the signal waveform as its
reference or timing point for each passing tooth on the reluctor.
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
generated. In this instance the MIL lamp will remain illuminated and the tachometer will fail to read.
It is vital that the CKP sensor output wires are not reversed (i.e. the connector is fitted incorrectly) as this will cause
a 3 advance in ignition timing. This happens because the ECM uses the falling edge of the signal waveform as its
reference or timing point for each passing tooth on the reluctor.
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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 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.
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.
Terribly Sorry I Forgot To Mention That The Vehicle Would Not Start One Night However The Next Morning Started After Repeated Tries.when Taken To Work That Night It Started But Then Failed To Start When The Shift Was Over 8 Hrs Later.i Did Code The Vehicle And Came Up With A P463 Fuel Sender Max Voltage And A Po1230 Fuel Pump Relay Failure Which I Did Switch With A Good One. Thanks Again For The Quick Reply Norm
