Fuel Injector Tester and Cleaner Machines for Shops

Updated November 2026

ASNU fuel injector tester and cleaner machines let fuel injection specialists, repair workshops, engine builders and dealerships test, clean and flow test injectors in house. Ace Fuel Systems became the first US distributor of ASNU equipment in 1994. We supply the machines, adapters and reconditioning parts your shop needs to offer professional fuel injector cleaning and flow testing to your customers.

Get in touch about ASNU equipment

Or call (833) 516-1598.

What does an ASNU fuel injector tester and cleaner do?

An ASNU machine runs injectors off the engine under simulated operating conditions, so your technicians can see and measure how each one performs. It then cleans them ultrasonically while they pulse and retests them. ASNU calls this injector diagnostics: testing injectors as a starting point for fuel system work, not a last resort.

On one bench, an ASNU machine lets your technicians:

Leak-down test each injector.
Inspect spray pattern and atomization through a backlit viewing window.
Measure flow rate in pounds per hour or cc per minute and compare it across the full set.
Check electronic operation across simulated pulse widths and RPM.
Clean ultrasonically in a dedicated tank while the injectors actively pulse. ASNU states the cleaning cycle takes about 20 minutes.
Retest after replacing sealing rings, protection caps and filter baskets, so the injectors go back as a matched, balanced set.

Optional software adds peak and hold current control and simulated RPM settings from a laptop or PC, and a variable voltage add-on shows how input voltage changes fuel delivery.

Which ASNU machine fits your shop?

It comes down to how many injectors you service at a time and which injector types come through your bays. The ASNU Classic GDI covers throttle body, port and gasoline direct injection, up to 8 injectors at once. The ASNU Junior tests up to 6 at once and suits port and motorcycle injector work, with more capability added through extra equipment.

	ASNU Classic GDI	ASNU Junior
Injectors per test	Up to 8	Up to 6
RPM simulation	Up to 20,000 RPM	Up to 10,000 RPM
Injector types	Throttle body, port, and GDI/FSI	Port and motorcycle as standard. GDI, marine and LPG with additional equipment.
Adapter options	Piezo GDI Adapter Box, 2-Stroke GDI Marine Adapter Box	GDI, marine and LPG equipment

Adapters that extend your machine

GDI/FSI Adapter Box: upgrades most analog ASNU machines to GDI capability.
Piezo GDI Adapter Box: adds piezo injector testing. Requires the ASNU Classic GDI.
2-Stroke GDI Marine Adapter Box: drives Evinrude E-TEC and Ficht injectors. Requires the ASNU Classic GDI.

Which injectors can ASNU equipment test and clean?

ASNU equipment tests and cleans gasoline injectors for automotive, motorcycle, marine and performance applications. That covers top feed and side feed port injectors and, with the right machine or adapter, GDI, FSI, piezo and 2-stroke marine injectors. ASNU machines do not test diesel injectors.

Top feed and side feed: machines come with adapters for top feed injectors, and side feed adapters are available for current side feed designs. Ace Fuel Systems manufactures adapters for new side feed applications as they reach the market.
Performance injectors: ASNU machines supplied in the US include a high-performance pump and a fuel rail built for high pressure.
Direct injection: ASNU tests direct injectors at low pressure, checking coil condition with inductance readings and inspecting spray and atomization. ASNU, working with injector manufacturers, determined this gives the most useful results.

Who uses ASNU injector testing and cleaning equipment?

ASNU equipment is built for businesses that service injectors for their own customers:

Aftermarket service and repair workshops
Fuel injection specialist workshops
Racing engine builders and high-performance tuning shops
OEM dealerships
Motorcycle performance, racing, service and repair workshops
Marine performance, racing, service and repair workshops

Why add professional fuel injector cleaning and flow testing to your service menu?

Injector faults show up as performance, fuel economy and emissions complaints, and replacing parts on a guess costs your customer money. With an ASNU machine, your technicians can confirm whether the injectors are the problem, restore them in house and show the customer before and after results.

Diagnose before replacing: ASNU’s position is that without injector diagnostics, a shop cannot correctly or economically solve problems on fuel-injected engines.
Keep the work in house: no sending injectors out to a third-party service and waiting for them to come back.
Show the result: before and after spray patterns and flow readings give your customer evidence of the work done.

Why buy ASNU equipment from Ace Fuel Systems?

The Ace Fuel Systems product line began in 1985, and in 1994 Ace Fuel Systems became the first US distributor of ASNU fuel injection equipment. Beyond the machine, Ace supplies the adapters, reconditioning parts and technical support that keep an ASNU bench working.

Authorized ASNU distributor and the first in the US, since 1994.
About 300 injector reconditioning part numbers, including filters, insulator washers and pintle caps.
Side feed adapters manufactured by Ace for new injector applications.
One-year parts warranty on ASNU machines.
Technical support from experienced carburetor and fuel injector technicians.

Fuel injector tester and cleaner FAQs

Which ASNU machine should a shop start with?

It depends on injector count and type. If you service GDI, FSI or piezo injectors, or need to test up to 8 at once, the ASNU Classic GDI covers them. The ASNU Junior tests up to 6 injectors and suits port and motorcycle work, with GDI, marine and LPG capability available through additional equipment. Get in touch and we will help you match a machine to your work.

Can an older ASNU machine be upgraded to test GDI injectors?

Yes, in most cases. The GDI/FSI Adapter Box upgrades most analog ASNU machines to GDI capability.

What consumables does an ASNU machine use?

Two chemicals. A calibration fluid, a Stoddard solvent with similar viscosity and specific gravity to gasoline but without its flammability, is used for flow and leak tests. A water-based, biodegradable chemical goes in the ultrasonic tank for cleaning.

Does ASNU equipment test diesel injectors?

No. ASNU machines test and clean gasoline injectors only.

Can an ASNU machine change an injector’s flow rate?

No. The machine brings an injector back to 100% of its original flow rate. Changing the flow rate means disassembling the injector and changing the orifice or pintle, which needs specialized equipment usually only available to manufacturers.

Can a shop supply a matched set of injectors with ASNU equipment?

Yes, by grouping. Manufacturers allow roughly 1% to 4% flow variation between injectors, so restored injectors can still differ slightly. Testing several injectors and grouping those with the closest flow rates produces a tighter matched set.

Where can I get reconditioning parts for injector servicing?

Ace Fuel Systems supplies about 300 part numbers used in injector reconditioning, including filters, insulator washers and pintle caps. Get in touch with the part numbers or injector types you need.

Talk to Ace about ASNU equipment for your shop

Tell us which injectors your shop sees most and how many you service at a time, and we will help you compare the ASNU Classic GDI, the ASNU Junior and the adapters.