2004 nqr isuzu ohc diesel fuel to pump, not to injectors

MIGHT NEED A NEW PRESURE REGULATOR

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.

big NQR TRUCK what model NQR 200, 300, what?
. what displacement engine, how many cylinders.?
Diesel right they only had gas in 1995 i think,
so is it direct injection (fuel rail direct?)
there are over 12, model H engines. 4Hxx all 12 are DI direct Inj.
so DI engines, have a ECU that injects. (much like modern gas engines,and huge injector pressure. , compared to port inj.)
so

1. check fuses first.
2. scan the PCM yet. ? that is 2nd, and mandatory.
3. fuel pressure good (tricky on Direct injection read the FSM yet)? Some engines have sensors here to see pressure, scanned
4. the PCM needs crank signals to inject. and reports them if bad.
5. the glow plugs work? i check voltage then use my current meter amp clamp tool to be sure all suck spec, current, if not fix that.

post real engine names.
and country

or google, "diagnosing direct injection"



.

fuel pump shot or fuel injectors plugged also check for loose wiring by your tank or by the injectors

do all the normal checks like if a diesel have the injectors checked . have the pump checked and the pump timing checked. Check that you are getting full throttle at the pump by having someone push the accelerator pedal to the floor and seeing if you can move the throttle lever further to the stop. If you are satisfied with everything being as it should be then I suggest a properly fitted turbo specific for your engine fitted by the shop that sells the turbo.

talk with a diesel pump specialist about alternative aftermarket injectors but I think that you will find that $2,000.00 per injector will be reasonable for 4 cylinder On isuzu diesel the injectors are around $6,000.00 per unit.. The secret is to ensure only ultra clean, good quality diesel fuel is used. The injectors and pump cannot handle any water in the fuel.

better chec the wiring or connections 1st--pull the plug from the pump and inspect for flaws and corrosion then plug back in--pump itself can be tested--the fuel injection pump in engine area may have issues

93 diesel rodeo won't start

possibly the fuel metering solenoid on the injector pump playing up was common
or injector pump itself
depending on which type of injector pump you have the round switch things on top rear section of pump that have a single or 2 wires to it.

First try replacing the fuel filter and also check the air filter element, if its clogged with dust replace.
After doing all this check the performance of the engine,if its still the same thn time to remove the injector nozzles for service.
The last option would thn be the pump(injector).
Hope this helps!