Cant start 4hl1 engine, crank but not start.., what is the problem ecm or fuse

no car told at all just 4hL1 Diesel floating in Isuzu space?
no year told 2005 (wild guess me)
the ECM gets all power from 2 things the power on relay and a fuse.
the shop manual is by the car or truck and year and model
the VIN number also tells what it is.
why post only and engine????? found it on some huge AC power generator or boat or what?

I say call Izuzu and ask them for the book, there is no other way.
no country told and ECU vary by, you guessed it too, country/;

Engine data plat is on valve cover. Some are forward some are at rear depending on year. The plate will give you info you need also next to plate will give you the horse power rating that is programmed into ecm.

what is the cause of no voltage in injector? except fuse. 4hl1 engine.

Knowing how it works is key , the ignition switch is a low voltage input to the BCM - body control module . When the BCM see's start input it sends a message over the serial data network to the PCM / ECM - engine computer . When the engine computer reads this message it will energize the crank relay sending B+ voltage to the S terminal on the starter solenoid ,there by cranking the engine . Taking to a qualified repair shop that has a factory or professional scan tool to read BCM DTC'S - diagnostic trouble codes is what you should do , before you cause more problems .

Circuit Description
Moving the ignition switch to the START position signals the body control module (BCM) through discrete inputs from the ignition transducer that engine crank has been requested. The BCM verifies that theft is not active and sends a serial data message to the engine control module (ECM)/powertrain control module (PCM) requesting engine start. The ECM/PCM receives a 12-volt signal from the park/neutral position (PNP) switch or clutch pedal start switch notifying that it is safe to start the engine. There is a splice on this circuit in the fuse block-underhood that supplies power for the starter relay coil. The starter relay coil control circuit is then grounded by the ECM/PCM closing the switch in the starter relay suppling 12 volts to the S-terminal of the starter. Ground is supplied through the engine block.

timing belt failure , immobilizer activated , crank/cam position sensor failure
run the fault codes first

Not start how ? When you turn the key to the start position what happens ? Does the starter engage an spin the engine ? If not ,this would be a no crank - no start Or when turning the key to start the starter spins the engine but it does not start an run , this would be a cranks - no start condition . So which of these is the problem your having ? An the likely hood of a fuse being the problem is astronomical , given the amount of electronic's on this vehicle . Anti-theft systems can come in to play an keep it from starting , sensor problems , the PCM - engine computer , fuel pump's not being turned on by the PCM/ECM .
This is from factory service repair manual , what happens when you turn the key to start your vehicle .
Circuit Description
Moving the ignition switch to the START position signals the body control module (BCM) through discrete inputs from the ignition transducer that engine crank has been requested. The BCM verifies that theft is not active and sends a serial data message to the engine control module (ECM)/powertrain control module (PCM) requesting engine start. The ECM/PCM receives a 12-volt signal from the park/neutral position (PNP) switch or clutch pedal start switch notifying that it is safe to start the engine. There is a splice on this circuit in the fuse block-underhood that supplies power for the starter relay coil. The starter relay coil control circuit is then grounded by the ECM/PCM closing the switch in the starter relay suppling 12 volts to the S-terminal of the starter. Ground is supplied through the engine block.

Your best bet , take it to a qualified repair shop.

no car stated, huge NPR truck no less.
no year stated
so no free book information on that engine,.
big diesel. 4HL1, no dash letter?
compression at spec.?
glow plugs work.,
filters clean. water in fuel,
does test fuel (spray'd) help? ???
injection problems
lack of startup air.(filter)


The 4HL1 is a common rail direct injection OHC 16V high-pressure fuel injection system diesel engine of 4.777 L capacity with electronic control system. Peak torque is 333 Nm, peak power is 140 PS (103 kW) at 3,000 rpm. Maximum torque is (34.0 kg m)'/1,500 rpm. Bore is 115 mm, stroke is 115 mm.
The 4HL1-N is a common rail direct injection OHC 16V high-pressure fuel injection system diesel engine of 4.777 L capacity with electronic control system. Peak torque is 333 Nm, peak power is 131 PS (96 kW) at 3,000 rpm. Maximum Torque is (34.0 kg m)'/1,500 rpm. Bore is 115 mm, stroke is 115 mm.
The 4HL1-TC is a common rail direct injection OHC 16 V turbocharged and intercooled high-pressure fuel injection system engine of 4.777 L capacity with electronic control system. Peak torque is 425 Nm, peak power is 160 PS (118 kW) at 2,700 rpm. Maximum torque is (43.3 kg m)'/1,500 rpm. Bore is 115 mm, stroke is 115 mm.
The 4HL1-TCS is a common rail direct injection OHC 16 V turbocharged and intercooled high-pressure fuel injection system diesel engine of 4.777 L capacity with electronic control system. Peak torque is 500 Nm, peak power is 179 PS (132 kW) at 2,700 rpm. Maximum torque is (51.0 kg m)'/1,500 rpm. Bore is 115 mm, stroke is 115 mm.

Weak battery- Low voltage while cranking
- Faulty Engine Control Module (ECM) relay
- Blown ECM fuse
- Faulty ECM
- ECM harness is open or shorted
- ECM circuit poor electrical connection

Do you know anything about automotive electronic's ,serial data communication's between control module's ?
Circuit Description
When the ignition mode switch is placed in the START position, a discrete input is sent to the body control module (BCM) notifying it that engine start has been requested. The BCM then verifies that the brake pedal has been depressed with a discrete input from the brake pedal position sensor and that the key fob, with the correct code, is in the vehicle. After this information has been verified the BCM grounds the control side of the RUN/CRANK relay closing the switch side of it and allowing battery positive voltage to flow from the BATT 3 fuse through the RUN/CRANK relay switch, engine control module (ECM) fuse to the battery positive voltage side of the CRANK relay coil. The BCM also sends a high speed GMLAN message to the ECM requesting engine start. The ECM will then verify that the internal mode switch (IMS) is in Park / Neutral or the clutch pedal is fully depressed. After this has been verified the ECM then supplies 12 volts to the control circuit of the CRANK relay closing the CRANK relay switch circuit and allowing battery positive voltage to flow through the STARTER fuse, the CRANK relay switch to the S-terminal of the starter solenoid cranking the engine. Ground is supplied through the engine block.

I also have a 96 LHS that randomly blows the 20 amp ECM fuse. If this is what you are referring to, the problem may be in one of your ECM sensors. 1-Start by unplugging all ECM sensors (Temp, Cam, Crank, 2-O2, TPS, etc.) and replace the fuse. 2-Crank the starter (the car will not start) and see if the fuse blows. If it does you probably have an electrical problem with the ECM. 2-If the fuse does not blow, plug in only the cam sensor and start the car; it will idle rough and the check engine light will come on. If the fuse blows, the problem is the cam sensor or wiring to it. 3-Continue plugging in sensors one at a time and try starting. When the fuse blows, you will know which sensor and/or wiring to the sensor to check. This process of elimination has worked twice for me.