In a bus fleet, every minute of downtime costs money. Yet some faults go unnoticed, simply because no engine warning light comes on. This is especially true for worn diesel injectors: they still operate, but gradually degrade engine performance — silently.
Here are 3 signs to watch for in your buses or coaches, even in the absence of fault codes, and how Jaltest INFO Web helps you diagnose them reliably and quickly.
1️⃣ Slow or Hesitant Cold Start
In the morning, a bus takes several seconds to start, even though it had no issues the day before.
➡️ Likely cause: Leaky injector when idle → Low rail pressure → Irregular combustion on start-up.
✅ With Jaltest INFO Web:
- Access to nominal rail pressure values during cold start
- Injector circuit leakage check procedure
- Step-by-step injector test guides by manufacturer (Mercedes, Iveco, MAN, Volvo, etc.)
2️⃣ Engine Vibration at Idle, Especially When Warm
The driver notices slight vibrations at idle, like a subtle engine shake — no warning lights, no dashboard messages.
➡️ Likely cause: Poor spray pattern → Combustion imbalance → Cylinder instability.
✅ With Jaltest INFO Web:
- Injector compensation value readings
- Accurate engine layout diagrams (Euro 5 / Euro 6)
- Support for injector swap testing or forced activation (when used with Jaltest diagnostic interface)
3️⃣ Increased Fuel Consumption + Slight Power Loss
On certain routes, the driver feels the bus has less pulling power and consumes more fuel — no smoke, no engine alert.
➡️ Likely cause: Sticky or misaligned injector → Uneven spray → Reduced engine efficiency.
✅ With Jaltest INFO Web:
- Access to OEM injector flow, injection timing, rail pressure
- Wiring diagrams for injectors and connectors
- Support for comparative analysis across injectors
⚠️ Why These Issues Often Go Undetected
In Euro 5 and Euro 6 engines, as long as the ECU receives signals within the “tolerated range”, no fault code is triggered.
But those signals don’t always reflect true injector wear: spray may be unbalanced, the injector slow to respond, or combustion may degrade — without the system recognizing it as a fault.
In many cases, it’s the driver who senses something isn’t right… but has no data to prove it.
🧰 Jaltest INFO Web: Your Diagnostic Assistant for Buses
With Jaltest INFO Web, you access complete technical documentation online — by brand, engine, fault code or symptom.
🚍 Coverage includes:
- Mercedes-Benz (OM906, OM926, OM471…)
- Volvo Bus (D9, D13…)
- IVECO Bus
- MAN, Scania, Setra, Renault Trucks, and more
You get:
✔️ Detailed injector specs and nominal values
✔️ Injection system & ECM wiring diagrams
✔️ Step-by-step testing procedures
✔️ Part references and sensor specs
✔️ Support for live data interpretation
➡️ And all this without needing an active fault code.
🚀 Detect Injector Wear Before It Becomes a Breakdown
A tired injector means:
❌ Higher fuel consumption across every route
❌ Increased emissions → risk of inspection failure
❌ Sudden breakdown if left unchecked
❌ Delays and missed schedules in the fleet
🔧 With Jaltest INFO Web, you turn every weak signal or inspection into a clear, accurate, professional diagnosis.
📲 Ready to Try?
✔️ Accessible via PC, tablet, or mobile
✔️ Works in tandem with Jaltest Diagnostic for live analysis
✔️ Training and demo sessions available with our team
👉 Request a demo or access at https://agridiaginfo.co.uk/free-trial/
🎯 Improve accuracy. Lower costs. Boost fleet reliability.
