5 Injector Fault Symptoms You Shouldn’t Ignore
Rough Idle? Might Be Your Injectors
Your injectors fire up to 30 000 times a minute.
When one goes out of balance, you’ll feel the difference fast—poor MPG, smoky exhaust, maybe even limp mode.
Below are the five red-flag symptoms we see every week on Trafic, Vivaro, Master and Movano vans.
1 · Diesel Knock at Idle
A metallic tap that disappears above 1 500 rpm often means one injector over-fuelling.
2 · Excessive Black or White Smoke
Black = too much fuel, white = unburnt fuel. Either points to poor spray pattern.
3 · Flat Spot on Pull-Away
Uneven injection timing can leave a dead zone between 1 200–1 800 rpm.
4 · High Fuel Trim / Correction Values
Clip / Tech2 “correction” above ±2.0 mm³ = injector out of spec.
5 · Hard Cold Starts
Leaky nozzle loses rail pressure overnight; crank time shoots past 3 s.
How We Diagnose in 60 Minutes
| Test | What It Shows | Time |
|---|---|---|
| Live Data (Clip / KTS) | Injector balance, rail pressure | 10 min |
| Leak-Off Test | Return flow within 10 % spec | 15 min |
| PicoScope | Electrical pattern & pilot injection | 15 min |
| Smoke Opacity | MOT-style check after repair | 10 min |
No parts darts. We confirm the faulty cylinder before you spend a penny on injectors.
Bench Testing
Ultrasonic clean & Bosch EPS 205 flow test — get a print-out of injector performance.
Pin-Point Coding
We recode new or reconditioned injectors so the ECU trims fuel perfectly on the first start-up.
Pricing Snapshot (ex-VAT)
| Service | From* |
|---|---|
| Full injector diagnostic | £90 |
| Ultrasonic clean & test (per unit) | £40 |
| New OEM injector + coding | £230 |
| Removal & refit (per unit) | £75 |
*Exact quote confirmed after diagnosis.
Stuck injectors may require specialist extraction (quoted separately).
FAQs
Can I keep driving with a faulty injector?
Short answer: **No.** Over-fuelling can wash cylinder bores, dilute oil and wreck the DPF. Fix it early, save the engine.Do you supply genuine Delphi / Bosch units?
Yes—every injector comes with a QR calibration code and 12-month warranty.Will coding erase my remap?
No, injector coding is stored separately from the main ECU calibration.Book Your Injector Check-Up
Call: +44 7751 216 895
Email: [email protected]
Workshop: Unit 5, Goodview Road, Basildon, SS14 3DN (appointment only)
Trusted for safety, chosen for expertise — let’s get your van running smooth and smoke-free.