4QT72ZH1 BQ2000 Inline Fuel Injection Pump for 490 Diesel

The application we stand behind is the 490 series four cylinder diesel: an in-line four, mechanically injected, water cooled diesel in the 2.54 to 2.67 litre class depending on the variant, built for forklift and small construction machine duty where a machine spends its life at low speed and high hours. That engine family carries the 490BPG and A490BPG and C490BPG designations in service, and the pump published against them is the one described here. Two things carry that application and they are the two the published data actually supports: the four cylinder engine family, and the set of physical dimensions on the pump. That is the diesel fuel injection pump this engine was built with, and an order that starts from the pump coming off is the one that arrives correct.

Three more identifiers worth having. If the machine is still with the customer, the engine code stamped on the block settles the variant faster than any chart. Where the pump is already off, a photograph of the data plate and a photograph of the drive end settle it instead. And a tape measure settles it better than either, because the three dimensions on this page are the ones that cannot be faked by a listing. Any one of those three alongside the plate reading is enough for us to confirm in writing; all of them together is what stops a family-number mix-up reaching your workshop.

Why the dimensions matter more than the number. The 4QT family covers several displacement and version segments under one shape, and a shortened form of the same designation circulates alongside the full one. Two machines carrying the same engine badge can therefore take different members of that family, and a buyer who matches on the string alone can end up with a pump that bolts on beautifully and is calibrated for something else. The dimensions are the answer, because a 14 to 17 mm taper with a 3 mm key and a 97 mm bolt circle belong to one physical build and not to the next. Match the plate, measure the three dimensions, confirm the governor and solenoid are present, then order. A mechanical fuel injection pump bought that way arrives right the first time, which is the whole point of the four steps above.

What this page is not claiming. We are not saying that a neighbouring 4QT number in the family fits your engine, that an overhaul kit number for the family is correct for this variant, that the published application covers a machine without a plate and measurement check, or that a pump from another family substitutes. 4QT72ZH-1 describes one build within a family, and the plate plus the three measurements are what identify it. Anything beyond those lines is better answered from your own parts data, and we would rather answer it with you than assert it here.

On a mechanically injected diesel the fuel circuit has three clear stages and this pump owns the third. A lift pump in the tank or beside the tank pushes fuel forward at low pressure. This inline mechanical high pressure fuel injection pump is what comes next, and it is the part that decides everything after that point: the engine camshaft turns four internal pumping elements against their cam lobes, and that mechanical action forces fuel up to injection pressure inside the housing. The delivery valves in the four holders along the top then meter what each cylinder receives, and the mechanical governor on the side moves the delivery rack to hold that volume steady as the engine speed changes. The stop solenoid is the one electrical part: it simply kills fuel when you turn the switch off.

The naming is where most ordering mistakes start, and on this number the mistake has a specific and expensive shape. 4QT72ZH-1 looks like an equipment manufacturer part number because it has the shape of one, and a buyer searching a catalogue will find listings where it is filed as an OE number. It is not. It is a model designation, and the same physical pump appears in catalogues under 490B-21001, under A490B-21001, under the model code BH4QT80R9, and under a shortened form of the type designation. A catalogue that indexes only one of those will tell you the part does not exist while you are holding it.

The third trap is the family. Within the 4QT group several displacement and version segments share one housing shape, so the difference between two numbers can be calibration rather than geometry. That is why this page leads on three measurements instead of on the string: the 14 mm to 17 mm tapered keyed input shaft, the three bolt slots on 97 mm centres at roughly 84 mm bolt to bolt, and the M14 banjo feed. Those three belong to one physical build. If all three agree, the shape is settled and only the calibration question remains, and that one we settle on the plate in front of us rather than on a chart.

Once the pump is fitted, each of the four delivery lines takes fuel to one cylinder, and that one-to-one arrangement shapes the diagnosis. A single worn injector or delivery valve shows up on one cylinder and leaves the other three steady. This pump feeds all four, so a fault inside it arrives everywhere at once and the diagnostic picture looks like a fuel system problem rather than a component problem. Our fault code guide covers how to read the codes that come with that, and the point of it is always the same: read the scan data and the pressure reading, not the code name.

When the pump stops behaving, the engine tells you through how it runs rather than through a warning light. A hard start that drags once the engine is warm. An idle that hunts and will not settle. Power that arrives fine at idle and disappears the moment the machine is worked. Each of these is examined properly in the symptoms section below, together with the fuel pressure comparison that separates a governing fault from a metering fault without guesswork.

Where our supply differs is what arrives rather than how the part works. Original equipment supply comes through a franchised channel, and a buyer whose paperwork requires a factory boxed part from a named manufacturer does need to go there. What we supply is a mechanical injection pump replacement — a new compatible unit for the same job, sold under the Vidishi Auto brand, plated with the same type designation, at a two-piece minimum with no core return. That last point matters more here than on an electronic pump: nothing has to come back, there is no exchange loop to manage, and the removed pump stays with you for the warranty file.

One thing we do not do is dress that up. The 4QT72ZH1 pump we ship is ours, not a manufacturer’s and not an engine maker’s, and we are not going to attach a famous parts brand to it to make it sound better. The part numbers and the pattern names appear on this page so you can match the pump you are replacing, and they are references for fitment rather than a claim about who made the part. The buying guides hold the general method for confirming any diesel part from the unit itself, and the glossary explains the terminology if any of the names above are unfamiliar.

How we label data. Confirmed means a value read directly from the goods we handle, including the type designation on the data plate and the governor, solenoid and delivery holders visible in the photography. Reference means a part number, a model code, a family designation or a mounting dimension quoted so your paperwork and your measurements can be matched, and carrying no claim about origin. Not published means the field is left blank on purpose — a pressure figure, a delivery volume or a component number that we cannot source would be worse than an empty cell, because it would end up in somebody’s parts order or somebody’s engine settings.

What is in the box. One complete inline mechanical high pressure fuel injection pump: the cast housing with its four internal pumping elements and cam bearing behind the cover, the four delivery valves and their holders clamped along the top with protective caps, the mechanical governor and its linkage on the flank, the electric stop solenoid with its electrical connector, the keyed drive stub and the idler flange, and the machined mounting feet as photographed. New sealing washers and a fresh filter element are required at fitting and neither is asserted as included for this line. Nothing on this page is sold loose from the pump, and internal service components keep their own listings for buyers who want a rebuild rather than a replacement.

Read the table from the top, because the order matters. 4QT72ZH1 is the supplier part number and it is the weakest identifier on the page: it tells you what this listing is, and nothing about which build is in the box. The row that identifies the unit is the one printed on its own data plate, 4QT72ZH-1, and that is the number you will find on the metal in your hand. Used as a 4QT72ZH1 cross reference map, the table is a boundary as much as a bridge. A parts system will match one form of a number and not the others, which is worth knowing before a search box tells you the part does not exist.

The BH4QT80R9 and BQ2000 style rows are there for identification the way a family name is on any catalogue entry, and it is worth reading them with care. They tell you which published pump pattern this assembly belongs to, which narrows the search and tells a parts clerk what sort of unit to look for on the shelf. They are not a statement that the unit in our box was made by whoever owns that pattern, because nobody here can evidence that, and the difference matters both legally and practically when a warranty claim has to be settled.

The three OE rows are the half of the mapping that catches people out, and the reason this page will not simply tell you they all fit. Published data places 490B-21001 and A490B-21001 and A490BPG-21000 against this pump, which means a buyer holding any of them may be asking for this assembly. It does not mean they are interchangeable on a given engine, because the family covers more than one calibration. Use those rows to recognise a unit you already have, not to authorise a purchase you have not verified. If you are holding a 4QT number that is not on this list, send it to us with the plate and the three measurements.

What the table deliberately does not do is extend itself. It does not say that a neighbouring 4QT number fits your engine, that a family overhaul kit is correct for this variant, or that a pump from another pattern substitutes. Those are exactly the assumptions that turn a cheap order into an expensive week of machine downtime, and we would rather leave the cell empty than fill it with a guess. Our comparison charts set out the number families we can evidence, and the buying guides cover the general method for confirming any diesel part from the unit itself.

The practical difference shows up on the test bench. When a fuel pressure reading will not hold up under load, the machine either runs on compromised delivery until something else breaks, or the workshop fits a known-good pump and the reading comes straight back. Keeping a matched spare — correct plate reading, correct taper, correct bolt circle, governor and solenoid present — turns a two-week machine stop into a same-week swap. That is the case for holding one of these on the shelf before anything has failed, and it is why the minimum order is set where a workshop pair, rather than a single unit, is the sensible purchase.

• Hard starting that drags when warm — A mechanical pump that has worn internally often shows its age on a cold start and then refuses to repeat it once warm, which is the opposite of most electrical faults and therefore misread more often than not.
• An idle that hunts and will not settle — Speed at low revs is held by the governing side, not by the metering side, so a hunting idle on a pump of this type points at the governor and its linkage. Check it for free play before ordering anything.
• Loss of power only when the machine is worked — When the machine is asked for more the pump has to deliver more, and that is the demand a tired unit struggles to meet. Power is fine at idle and disappears the moment the engine is worked, which is exactly what makes it easy to misread.
• Smoke under load — Fuel delivered at a volume the engine did not ask for will not burn the way it should, and it leaves the stack as smoke. On this pattern that points at the pump or at the injectors, and the way to tell the two apart is the four cylinder test below.
• Fuel consumption climbing faster than the hours — A unit that is metering more than the engine needs makes the gauge move faster than the work justifies, and on a forklift that is a running cost rather than a comfort complaint.
• Fuel pressure that will not hold up under load — The measurement that settles it. A pressure reading that will not reach the figure for your engine, taken idling and then loaded, points at the pump when no filter or injector work moves the reading.
• All four cylinders affected together — The pattern worth holding on to. A single worn injector shows up on one cylinder and leaves the other three steady. One pump feeds all four, so a pump fault arrives everywhere at once and that single distinction does more diagnostic work than any code name.
• A fault code on the pressure or quantity side — A code reported against fuel pressure or injection quantity belongs on the list, because this pump produces and meters both. Read the scan data rather than the code alone, because a code names a circuit and not always the part.

The pattern worth holding on to is the one that affects every cylinder together. A single worn injector or delivery valve shows up on one cylinder and leaves the machine steady on the other three. A tired inline fuel injection pump takes the whole engine down together, because one pump feeds all four lines. That single distinction does more diagnostic work than any code name, and it is why we would rather you bring us a pressure reading than a code you have decoded from a list. The fault code guide explains how to read the data behind the code, and our maintenance guide covers the filter and water separator intervals that keep this circuit healthy.

• Step 1. Drain, depressurise and mark the drive position
  Let the system stand, release residual pressure, and before anything is unbolted mark the position of the keyed drive shaft against the pump housing. A cam driven pump must go back on the same position, and the mark is the only thing that guarantees it.
• Step 2. Flush the system if the old unit failed internally
  If metal is present in the fuel, replacing only the pump destroys the new one just as fast. Drain the tank and the lines, fit new filters, and only then fit the new unit. This step is the single biggest cause of a second failure.
• Step 3. Clean the mounting face and the feed banjo before opening anything
  Wash around the pump, blow the sealing face down, and check that the banjo seat is not dished or damaged. Grit that falls onto that face ends up between the two surfaces, and the new pump will weep from its first minute.
• Step 4. Unbolt evenly and support the housing
  Work the three bolts in sequence rather than freeing one corner at a time. The housing has to lift square off the engine rather than at an angle, and that tapered drive shaft must never be levered against the cam.
• Step 5. Inspect the drive shaft, the key and the coupling
  Check the taper, the keyway and the surrounding material for wear, scoring and burrs. A drive that has been turning against a worn coupling will damage the new pump in its first hour of running, and the taper is the surface that has to seat properly.
• Step 6. Fit new seals and a fresh filter element
  A fresh sealing washer goes under the refitted pump, and the filter element is renewed rather than reused. Reused seals and a reused element are among the most common causes of both a weep and an early return of the same fault.
• Step 7. Refit square, time it, and torque to the engine figure
  Drop the pump into the marked position, align the drive correctly, bring the mount up evenly and torque to the figure for your engine. The figure belongs to the engine and not to the part, and we do not publish it for this number.
• Step 8. Prime, bleed and verify before the machine goes back to work
  Fill and bleed the system until it shows no air, confirm the stop solenoid connector is seated, then verify fuel pressure against the figure for your engine at idle and under load before the machine returns to service.

Two notes on what we deliberately do not print. We do not publish the tightening figure for the mount, the injection pressure figure, or the timing angle, because all three belong to the engine application rather than to the part, and a figure copied from a product page into a workshop manual is how a good pump gets damaged on a correct fit. Take them from the engine manual for the machine in front of you. And we do not publish a diesel fuel injection figure as a shortcut, because the mount, the delivery lines and the feed banjo each have their own value and they are not interchangeable. The installation guide covers the surrounding routine, and the glossary defines the terms if any of the above are new to you.

Every 4QT72ZH1 pump is covered by a 12-month warranty against manufacturing defects. That covers a unit that arrives out of specification or fails early because of how it was made. It does not cover damage from contaminated fuel, from water in the system, from a filter changed too late, from incorrect fitting, from a drive shaft torqued beyond its figure, or from a separate fault elsewhere in the fuel circuit. It is a supplier warranty from Vidishi Auto, and no manufacturer or engine brand warranty travels with this part, because we are not a dealer for any of them.

The one condition we ask about every time is whether the system was flushed when the old unit came out, because that is the single most common reason a replacement injection pump fails early and the single easiest thing to get wrong on a job where somebody is under time pressure. Tell us what was done and we can tell you quickly whether a claim is likely to stand. If you would rather settle that question before you order, the contact page is the fastest route to a written answer.

The minimum order quantity is 2 pieces, and the reasoning is worth stating rather than leaving you to work out. Demand for an injection pump of this type comes in workshop batches rather than one at a time, because a failure takes a forklift or a machine off the road and the repair is done once, properly. Two pieces covers a workshop and lets one pump sit on the shelf as the known-good unit for a pressure test before anything else is committed. From there the line scales normally — a fleet running several machines will take a set per machine, and a distributor will take them alongside the rest of a fuel system order.

What we do not do on this line is pretend the part is something it is not. The unit we ship is a new compatible replacement sold under the Vidishi Auto brand. It is not a manufacturer-branded product, it is not an engine maker’s own part, and it is not a factory boxed original. That matters commercially as well as legally: if your incoming goods inspection needs a specific brand on the paperwork, this is not that product, and we would rather tell you now than have a delivery rejected. The help centre covers ordering and documentation questions.

The package size and gross weight in that table are a packing estimate, and we label it that way rather than quietly presenting it as a specification. Two supplier listings for this same pump give different single package figures, so neither is adopted here and no source we can stand behind publishes a packaged figure we can evidence. If your freight is calculated on volumetric weight rather than actual weight, tell us the destination and we will confirm the chargeable weight against the carton we actually use. The shipping page sets out the full documentation and delivery terms, and the order tracking page is where to follow a shipment once it has left.

On the protective side, the two areas we watch are the keyed drive stub and the delivery valve holders on the top of the housing. A scored keyway will not seat properly on the coupling and will damage the new pump within hours, and a bent holder is a fault that looks like a metering problem for weeks afterwards. Both are packed protected on every unit, and both are worth checking on arrival before the box goes into stores.

A mechanical injection pump is a small number of large, precisely machined parts, so this line is checked at unit level rather than by sample. Every batch passes an incoming check for the type designation on the black data plate, a measurement of the input taper and key, an inspection of the mounting feet and the three bolt slots, a confirm that the mechanical governor and the stop solenoid are present and undamaged, a check that the four delivery valve holders and their caps are clean and complete, a confirm that the feed banjo and the spill port are free of obstruction, and a packed-weight confirmation against the documented figure. The supplier shows an ISO 9001 system certification badge on the product photography, which we record as a supplier statement rather than as a certificate we issue.

Rather than publish reviews we cannot verify, we tell you what we will actually put in writing: a written fitment confirmation against the plate reading and the three measurements you send us, a written quote against your quantity and destination, and a warranty position on any claim that follows. If you need a supplier who will sign a specific inspection or conformance document with the order, ask before you buy rather than after, because the answer depends on what the document is. The help centre covers the documentation we can provide, and the partner programme page is the route for a standing arrangement that needs more than a one-off order.

Support is not an add-on on this line — it is how most of these orders get placed correctly. It costs nothing before you buy: send the type designation read off the data plate of the unit you are removing, the three mounting measurements, the engine code and the machine details, and we check the whole set against what we supply before quoting. The measurements are the item people skip, and they are the item that matters most here, because the 4QT family covers several calibrations under one housing shape and a string match cannot tell them apart. Two minutes with a tape measure in hand is cheaper than a pump that arrives and does not settle the fault.

Two things we will not do, whatever the order size. We will not quote a fitment we cannot evidence, and we will not ship a pump matched on a designation string when the plate and a tape measure are available. If that costs us an order, it is still the right call: an injection pump that arrives mismatched costs a workshop a second removal, and that is the failure we exist to prevent. If anything on this page is unclear, the contact page lists every route to us, and a written answer is always better than a guess on a workshop schedule.