Diesel injector testing in Coventry

Misfire, smoke or heavy fuel use? Find out which injector is at fault before you pay for a rebuild or a new set. We test diesel injectors on a bench at our Coventry workshop and give you a written report for each one.

What we measure

Every injector goes through the same sequence of tests on the bench. We use OE-level Hartridge and Bosch test benches. The test includes:

• Resistance check of the injector.
• Nozzle opening pressure.
• Spray pattern, so you can see how well the fuel is atomised.
• Delivery rates at idle, mid and full load.
• Backleak measurement.

What you get back

A detailed PDF report for every tested injector. You see which injectors are in order and which are not, so you only pay to fix what is actually worn. Turnaround is usually within 24 to 48 hours once your injectors reach us.

When an injector test is worth doing

• Rough idle or misfiring.
• Black, white or blue smoke.
• Poor fuel economy.
• An engine management light or an injector fault code.
• Hard starting or a knocking noise.

Testing also helps when more than one injector may be involved. Instead of replacing a full set on a guess, you find the ones that are actually at fault. Our guide explains the signs in more detail: diesel injector testing, do you need it or just a replacement.

After the test

If your injectors pass, you refit them and the guesswork is over. If one or more are worn, you can have them rebuilt. We work on an exchange basis or repair your own units, and the testing charge is credited if we rebuild them. A rebuilt injector carries a 12-month warranty. Read more on our reconditioned diesel injectors page.

A new or rebuilt injector also needs its code entered into the engine computer. See injector coding explained.

How to send your injectors

Post or courier them to our workshop, or bring them in during opening hours. Please call or message us first on 07452 738887 so we know to expect them. Tell us the make, model and engine of the vehicle and the symptoms, and label each injector with its cylinder number so the report matches your engine. Ask us for the current testing rate when you get in touch.

Related: Reconditioned diesel injectors Injector repair cost Injector coding Testing guide