You can test a diesel injector at home by performing an electrical resistance check with a multimeter and a visual spray pattern test (with extreme caution for safety!), but for precise mechanical and spray pattern checks, professional equipment is needed, especially for common rail engines; a multimeter tests the coil's ohms (comparing to specs), while a spray test checks for atomization, not a stream, and involves removing the fuel rail, which can be messy and risky.
Listen with a mechanic's stethoscope: a healthy diesel injector has a regular clicking/actuation sound; a dead or weak injector will sound different or silent. - With proper diagnostic tools, disable each injector one at a time and observe RPM drop. A significantly different RPM change identifies the weak injector.
To test for possible damage to the fuel injectors, you'll need a good pair of earplugs, a battery gauge, and a multimeter. First, plug in your multimeter to the positive battery terminal. Next, turn the engine on and plug in your earplugs. When the meter reads 0 volts, you're all set to begin testing.
Signs of a Bad Fuel Injector
Spray penetrating oil like WD-40 or PB B'laster on the injection pump. You might need to let it soak overnight so you can continue unsticking a stuck injection pump. Gently tap the pump if necessary to help free it up.
Using a fuel injector cleaner is one of the simplest and most cost-effective solutions. These cleaners are added to your fuel tank and work to dissolve deposits within the injectors. Regularly using a high-quality fuel injector cleaner can prevent clogging and maintain optimal injector performance.
Fuel injectors work as a set, and replacing just one can lead to imbalances in your engine's performance. When one injector fails, it often indicates that the others are nearing the end of their lifespans too. Replacing all injectors at once ensures consistent fuel delivery and optimal engine performance.
The test costs from £15.00 + VAT per injector. If you need us to remove the injectors to carry out the test we charge labour to do this according to where they are & what needs to be removed to access the injectors. PD injectors ( Pumpe Duse) can be sent away for testing. This will take 4-5 working days.
A faulty injector that consistently dumps excess fuel can damage the catalytic converters. When unburned fuel enters the catalyst, it can combust. The extreme heat given off by combustion can wreak havoc on the inside of the expensive catalyst.
Here are several clues that could point to a stuck injector:
Testing and cleaning a fuel injector, step by step
How to Bleed Air Out of a Diesel Fuel System
There is one per cylinder, typically a black plastic housing installed directly above the cylinder. Place the tip of a long screwdriver on the top of the fuel and place your ear on the handle. (Yes, this actually works, stop looking at us that way.) You should hear a regular clicking as your injector cycles on and off.
Is unplugging injectors one by one at idle a reliable home test? It's useful but imperfect. A bad injector may cause little to no RPM change when unplugged.
Automotive repair specialist Duston Maynes recommends using an automotive-style stethoscope to check your fuel injectors. These devices have a long tip that looks almost like a needle, and you place it on top of the injectors to listen for a clicking sound (which means it's functioning properly).
A dirty fuel injector can affect your car's performance, but it doesn't always need to be replaced. Sometimes a good cleaning can solve any issues, at least temporarily.
It takes about 3 weeks of sitting for it to start clogging. This car has previously sat for quite some time during the pandemic, but it ran fine even after a few more tanks of fresh gas.