No start... except with starting fluid.
#11
04-19-2018, 03:07 AM
Camel Trophy
Join Date: Oct 2016
Location: St. Clair County, Michigan
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Hi there! Fuel pump is running. I have 40 psi at the fuel rail when I'm trying to start it. And after I get it started with the spray... It runs good with no symptoms of fuel issues.
It is almost like the fuel injectors are not working until the engine is spinning fast for a bit???
It is almost like the fuel injectors are not working until the engine is spinning fast for a bit???
Brian.
#12
04-19-2018, 03:23 AM
Camel Trophy
Join Date: Oct 2016
Location: St. Clair County, Michigan
Posts: 4,550
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Another quick thought, how long has it been since your last tune-up? I've seen vehicles start on ether, but not start on gas when cold...that just needed a good old fashion tune-up. Especially, if it is a high mileage engine (low compression). Also, while running...check vacuum readings. This will tell you a lot about the condition of the engine.
Brian.
Brian.
#13
04-19-2018, 10:50 AM
No idea when the last tune up was. After running the engine and driving it around... it will not restart when turned off. So it will not start when the engine is up to temp as well. Does anyone know if there is only one temp sensor that does both the engine management information as well as the gauge on the dash? Will values need to be reset if I unplug it while it's running to check it? Thank you for all the help guys!
#14
04-19-2018, 11:04 AM
I think that I should say again that there is NO sign of the engine firing while cranking. Not a single cough or the smallest little explosion in a cylinder. It acts like the fuel pump is not on. It will crank for minutes like that. Until I give it a few explosions from starting spray... it's like it tricks the computer into firing the fuel injectors. Anyone know how the fuel injectors are managed by the computer on a disco 1?
#15
04-21-2018, 07:22 PM
Pro Wrench
No start when hot may rule out the CTS however it's probably worth checking with a meter to see if it's in spec. I can't advise you on how the fuel injection works but it's highly unlikely that the starting fluid is tricking anything into running. How does the truck run otherwise? Have you checked for vacuum leaks? I've never looked at the harness but it may also be worth getting a noid light and see if the ECU is firing the injectors. Assuming you can disconnect an injector without too much trouble it will be very easy to tell if the injectors are being pulsed. You can also pull a spark plug and see if there's fuel on it after an unsuccessful start.
#16
04-22-2018, 10:34 AM
#17
05-16-2018, 09:58 PM
So... I finally got a set of fuel injector testing lights. The injectors do NOT fire during cranking. (No light flashing) But the DO after hitting it with some spray. (Light flashing like crazy) My tachometer does not move during cranking and I understand that the ECU needs to see a tachometer signal to fire the injectors (80 rpm). Sounds like the computer gets its signal from the alternator?!?!?... anyone know anything about this? I woul love to jimmy rig it some how to get it running if possible... or anyone have a extra good alternator? Thanks for your help guys!
#18
05-17-2018, 07:44 AM
TReK
#19
05-17-2018, 07:49 AM
TReK
Here are the inputs to the ECM... (from GEMS_Systems.pdf)
System Inputs
The ECM is mounted in the engine compartment. The expanded list of ECM inputs is as
follows:
• Crankshaft Position (CKP) Sensor
• Ignition Signal (Key on signal)
• Camshaft Position (CMP) Sensor
• Knock Sensor (KS)
• Intake Air Temperature Sensor
• Engine Coolant Temperature (ECT) Sensor
• Engine Fuel Temperature (EFT) Sensor
• Throttle Position Sensor (TPS)
• Mass Air Flow Sensor (MAFS)
• Park/Neutral Position Switch (PNPS)
• Heated Oxygen Sensors (4)
• Fuel Level Sensor
• Heated Front Screen
• Road speed (Range Rover)
• Air Conditioning request
• Battery Voltage
• Cooling fan request
• Security link
• ABS link
Several of these inputs (road speed, A/C request) originate in the ABS Module and are received
via the Body Control Module.
CKP sends RPM info to ECU, but you'd get a 'check engine' light if that were not working.
Do you have an OBDII reader?
System Inputs
The ECM is mounted in the engine compartment. The expanded list of ECM inputs is as
follows:
• Crankshaft Position (CKP) Sensor
• Ignition Signal (Key on signal)
• Camshaft Position (CMP) Sensor
• Knock Sensor (KS)
• Intake Air Temperature Sensor
• Engine Coolant Temperature (ECT) Sensor
• Engine Fuel Temperature (EFT) Sensor
• Throttle Position Sensor (TPS)
• Mass Air Flow Sensor (MAFS)
• Park/Neutral Position Switch (PNPS)
• Heated Oxygen Sensors (4)
• Fuel Level Sensor
• Heated Front Screen
• Road speed (Range Rover)
• Air Conditioning request
• Battery Voltage
• Cooling fan request
• Security link
• ABS link
Several of these inputs (road speed, A/C request) originate in the ABS Module and are received
via the Body Control Module.
CKP sends RPM info to ECU, but you'd get a 'check engine' light if that were not working.
Do you have an OBDII reader?
Originally Posted by Workshop Manual
Relay module
The engine management system employs a relay
module, which houses the main relay and the fuel
pump relay.
Main relay
The main relay supplies the power feed to the ECM
with a tap off to feed the fuel injectors (8 amps) and
air flow sensor (4 amps). This relay is controlled by
the engine management ECM. This enables the ECM
to remain powered up after ignition is switched off.
During this ’ECM power down routine’ the ECM
records all temperature readings and powers the
stepper motor to the fully open position. Failure of this
relay will result in the engine management ECM not
being switched on resulting in engine not starting due
to absence of fuel and ignition.
Fuel pump relay
The fuel pump relay is fed from the ignition relay and
controlled by the engine management ECM. The relay
is activated in ignition key position 2 to prime the fuel
system for a period of time controlled by the ECM.
Failure of this relay will result in no fuel pressure.
The engine management system employs a relay
module, which houses the main relay and the fuel
pump relay.
Main relay
The main relay supplies the power feed to the ECM
with a tap off to feed the fuel injectors (8 amps) and
air flow sensor (4 amps). This relay is controlled by
the engine management ECM. This enables the ECM
to remain powered up after ignition is switched off.
During this ’ECM power down routine’ the ECM
records all temperature readings and powers the
stepper motor to the fully open position. Failure of this
relay will result in the engine management ECM not
being switched on resulting in engine not starting due
to absence of fuel and ignition.
Fuel pump relay
The fuel pump relay is fed from the ignition relay and
controlled by the engine management ECM. The relay
is activated in ignition key position 2 to prime the fuel
system for a period of time controlled by the ECM.
Failure of this relay will result in no fuel pressure.
Last edited by WaltNYC; 05-17-2018 at 08:00 AM.
#20
05-22-2018, 08:55 PM
Hi there!!! Thanks for the reply... and sorry for my slow response. I do have a obdII reader... but have no check engine light on...and no stored codes at this time.
Interesting about the main relay... but I think mine is working as I do have spark while cranking.
Fule pump is on.
Have you ever heard anything about the "80 rpm to turn on fule injectors" before... or was that BS. I know some people have running trucks with the tachometer not working.
Lol. I'm about to wire up my own cold start valve into the intake plenum and get on with my life as it is driving me a lil crazy at this point... and all the starting fluid can't be good for things. Thanks for the help :-)
Interesting about the main relay... but I think mine is working as I do have spark while cranking.
Fule pump is on.
Have you ever heard anything about the "80 rpm to turn on fule injectors" before... or was that BS. I know some people have running trucks with the tachometer not working.
Lol. I'm about to wire up my own cold start valve into the intake plenum and get on with my life as it is driving me a lil crazy at this point... and all the starting fluid can't be good for things. Thanks for the help :-)