Our Diesel Engine Services Frequently Asked Questions

A diesel engine specialist will diagnose issues using advanced equipment and repair or refurbish the injectors, fuel pumps and other related parts. They also provide engine remapping services, performance tuning and fuel system checks to improve your vehicle's power, reliability and fuel economy.

You should take your diesel car or van to a specialist like Gee Diesel Services Ltd when there are problems with the fuel system or engine. If you notice issues like hard starting, loss of power, high fuel use, smoke, knocking sounds or warning lights linked to the injectors or sensors, it's best to come to us instead of a normal garage. This is because a typical garage might not have the tools to test these parts properly.

Most diesel engines need servicing every 10,000 to 12,000 miles or once a year, whichever comes first. At Gee Diesel Services Ltd, we recommend having regular checks because diesel engines rely on clean oil, good filters and a healthy fuel system to stay efficient. If you drive in heavy traffic or cover long distances, frequent servicing can help prevent wear and engine damage. Routine checks can keep the injectors, sensors and pumps working well and reduce the risk of faults or failures. Sticking to a clear service schedule also helps your engine run smoothly and maintain good fuel economy.

Serious diesel engine problems often have clear warning signs, such as hard starting, sudden loss of power, heavy smoke, rising fuel use, strong knocking sounds or engine warning lights that stay on. You may also notice rough idling, poor acceleration or a strong fuel smell. 

Gee Diesel Services Ltd can run detailed tests to check the injectors, pumps and sensors to find and fix the issue quickly. If your engine feels unsafe, louder than normal or struggles under heavy usage, you should book a diagnostic appointment as soon as possible.

A diesel engine specialist can improve both your vehicle's power and fuel economy through careful diagnostics, tuning and servicing. By checking the injectors, pumps, sensors and air systems, we can make sure the engine burns fuel cleanly and efficiently. 

We can also provide safe remapping services to adjust your engine so that it provides stronger pulling power at lower engine speeds, which often reduces your fuel usage on normal roads.

Diesel engine remapping involves changing the ECU software to control how your engine works. A specialist will read the original settings, then adjust your fuel delivery, boost pressure and timing so the engine runs more efficiently. This can improve your power, torque and throttle response while helping the engine work at lower speeds on normal roads.

Engine remapping is safe for diesel cars or vans when it's performed by a trained specialist. At Gee Diesel Services Ltd, we can inspect the engine, injectors, sensors and fuel system before any work is done to make sure your vehicle is in good condition. 

We will then adjust the software in controlled steps so the engine stays within safe limits; this protects the turbo, clutch and gearbox. A careful remap can make your engine run smoother, stronger and more efficient without harming its reliability.

A well-written remap from Gee Diesel Services Ltd can improve your fuel economy. By adjusting the fuel delivery, timing and boost levels, we can make your engine produce more torque at lower speeds. This means you can drive in higher gears with less effort, which also reduces your fuel usage on normal roads. 

Remapping can cause problems, but only if it's done incorrectly. At Gee Diesel Services Ltd, we implement safe settings to keep the engine, turbo and gearbox within their limits. This helps us avoid damaging your vehicle and ensure it's reliable on the road. Most issues happen when cheap or copied maps are used since they can push the engine too hard. 

As for warranties, some makers may refuse to cover your vehicle if they find any software changes. However, we can explain these risks before starting any work.

A diesel remap usually takes at least one to two hours, depending on your vehicle. We will start by testing the engine to make sure it's healthy before reading the original software, adjusting the settings and uploading the new map. 

Remapping is reversible because the original file is stored away before we make any changes. So, if you ever want to return the vehicle to its factory settings, we can simply reload the original file.

A diesel fuel injector delivers the right amount of fuel into the engine at the right pressure so that it can burn cleanly and produce power. Each injector needs to spray the fuel in a fine mist at the right moment; if not, the injectors can become damaged or blocked. If there is a blockage, you'll notice issues like smoke, hard starting, poor fuel use or rough running.

A bad diesel injector can change how your vehicle runs. In this case, you may notice issues like hard starting, rough idling, a drop in power, as well as black or white smoke coming from the exhaust. Tapping or knocking sounds are also signs that there's an issue with the fuel injector.

Diesel injectors can be cleaned if the problem is caused by small deposits or light blockages. We can use test equipment to check the spray patterns and pressure before deciding on the best course of action. If cleaning restores the fuel flow, the injector can be reused. However, if parts inside the injector are damaged, it's often best to replace them.

The price of repairing or replacing diesel injectors will vary depending on the injectors' condition. We will test the injectors first to see if we can repair them, which usually costs around £200 per injector. However, a full replacement with new or refurbished units will cost more, with price ranges of £150-£500 per injector.

Yes, faulty injectors can cause long-term engine damage if they're ignored. When an injector sprays too much fuel, too little fuel or sprays it in the wrong pattern, the engine can't burn fuel cleanly. This can lead to high cylinder temperatures, excess smoke, rough running and extra strain being put on the pistons, valves and the turbo.

Diesel diagnostics is the process of finding faults in a diesel engine using specialist tools and knowledge. We will connect advanced diagnostic equipment to the vehicle to read fault codes and live data from the sensors, injectors and the fuel system. This helps us find issues like weak injectors, boost leaks, sensor errors or poor fuel delivery.

We will then perform more tests to confirm the cause of the issue, such as injector balance checks or pressure tests. Our accurate diagnostics prevent guesswork and ensure your engine runs smoothly and reliably.

A diesel engine light can come on for several reasons; the common reasons are faulty sensors, poor fuel delivery, weak injectors, blocked filters or problems with the turbo system. Sometimes the issue can be small, but it can also point to a serious issue that may affect your vehicle's power or fuel use.

Yes, a diagnostic check can find hidden problems that aren't easy to spot during normal driving. We use advanced tools to read live data from the sensors, injectors, the turbo and the fuel system to uncover issues such as weak injectors, boost leaks, pressure faults or timing problems.

A diesel diagnostic test usually takes between 30 minutes and 1 hour, depending on the issue and how much data needs checking. We can read the fault codes and live engine data, and we can conduct more tests if the results show deeper issues.

No, you typically don't have to fix everything that appears on a diagnostic report. Gee Diesel Services Ltd will explain which faults need urgent attention and which ones are minor. Some issues may not affect how your vehicle drives, while others can lead to engine failures if they're left too long. A clear report from us can help you decide what to repair now and what to keep an eye on.

A diesel particulate filter is a part of the exhaust that traps soot to keep your emissions low. This filter stops harmful particles from entering the air and helps your vehicle meet clean air rules. Over time, the filter fills up with soot and needs to regenerate by burning it off. If this process fails, the filter can block and cause power issues.

A loss of power, higher fuel use, frequent regeneration attempts, strong exhaust smells or the DPF warning light on the dashboard are all signs that the DPF is blocked.

A blocked DPF can often be cleaned, depending on how severe the build-up is. We can run diagnostic checks to see if a forced regeneration or off-vehicle cleaning will restore your fuel flow. However, if the filter is damaged, cracked or completely overloaded with ash, replacing it is the safest option.

You can stop your DPF from becoming blocked by keeping the engine healthy and letting it complete its cleaning cycles. Regular servicing also helps keep the sensors, filters and injectors working well. You should avoid short trips whenever possible because the engine needs enough heat to burn off the soot; a longer drive at a steady speed can help the filter stay clear.

No, it's not legal to remove a DPF from any vehicle in the UK when it's on the road. If the filter is taken out, the vehicle will fail its MOT, and you can also receive fines from enforcement officers. Keeping the DPF in place protects the engine and reduces air pollution.

AdBlue is a fluid that's used in diesel vehicles to help reduce the amount of harmful nitrogen oxide emissions being released. It's injected into the exhaust system, where it reacts with the gases to make them cleaner. 

If the AdBlue tank runs low, the engine may experience performance issues or refuse to start. We can diagnose AdBlue system faults, reset the warning lights and ensure the system works correctly to keep your vehicle compliant and efficient.

If your AdBlue tank runs dry, you'll usually see warning lights and messages appear on the dashboard. You may also notice a reduction in power, or your vehicle may not restart if it's switched off until AdBlue is added. This is to make sure your emissions stay within legal limits.

You can refill AdBlue yourself since most vehicles have a clear filling point near the fuel cap. However, if the warning light stays on after refilling, it's best to book in with a specialist.

An AdBlue warning light can stay on after a refill for many reasons. One of the main reasons is that the system needs time or a short drive to recognise the new AdBlue level. However, if the light doesn't turn off after that, there could be an issue with the sensor, pump, heater or the AdBlue quality.

Yes, a specialist can usually find and fix any AdBlue system faults and sensor issues. We use diagnostic tools to read fault codes and check the pumps, heaters, level sensors and wiring, and repair any damage. This helps fix your AdBlue dosing and keeps your emissions within UK limits.

The most common diesel engine repairs are fixing or replacing faulty injectors, sensors, fuel pumps and glow plugs, as well as fixing issues with the turbo, EGR valve or DPF. Cleaning the fuel system, repairing air leaks and fixing boost problems are also common engine repair services.

The main signs your engine needs an urgent repair are a sudden loss of power, heavy smoke, strong knocking sounds, high fuel use or the engine warning light staying on. You may also notice hard starting, rough idling or the engine going into limp mode. These signs can point to serious faults with the injectors, the turbo or the fuel system.

Repairing or replacing a diesel engine depends on the amount of damage there is and your vehicle's overall condition. Gee Diesel Services Ltd can run detailed checks to assess your vehicle's wear, compression, injector health and fuel system performance. 

Many faults can be repaired, especially issues with the injectors, sensors or pumps. However, if the engine has severe internal damage or repeated failures, replacing it is the more reliable option.

Simple fixes like sensor or injector repair work can often be completed within a day. On the other hand, more complex jobs such as fuel pump repairs or internal engine repairs can take several days to complete.

At Gee Diesel Services Ltd, we can explain what's covered by our warranty before any work begins. Most warranties often depend on the parts that are used and any subsequent service advice. We also keep your invoices and service records safe to help protect you if you return with a problem after the repair.

A diesel fuel pump delivers fuel from the tank to the engine at the right pressure so that your vehicle can run smoothly and produce power. Modern pumps need to supply steady, high-pressure fuel in order for the injectors to work properly.

A failing diesel fuel pump can cause hard starting, power losses, rough idling and poor acceleration. You may also notice higher fuel use, smoke, misfires or the engine cutting out under heavy usage, and in some cases, the vehicle may not start at all. These symptoms appear because the injectors aren't receiving enough fuel pressure.

A diesel fuel pump can be repaired if the problem is caused by worn-out seals, minor internal faults or contamination. Gee Diesel Services Ltd will test the fuel pressure and flow to see if a repair service is possible. However, if the pump has serious internal damage, heavy wear or electrical issues, a replacement service is usually the safer choice.

Yes, a bad fuel pump can make starting your vehicle difficult because the engine isn't receiving enough fuel pressure. You may also notice a reduction in power, poor acceleration, rough idling or the engine cutting out. These problems happen when the pump can't supply a steady flow of fuel to the injectors.

On average, you can expect to pay around £500 for a fuel pump repair service, since most prices range from £300 to £900 depending on the severity of the damage.

Diesel performance tuning is the process of adjusting a diesel engine to improve your power, torque and response while keeping it safe and reliable. Gee Diesel Services Ltd uses advanced diagnostics and tailored software changes to optimise your fuel delivery, boost control and timing, which helps the engine pull stronger at lower speeds and also supports better fuel use.

Remapping changes the software inside the engine control unit, giving precise control over your fuel delivery, boost and timing. A tuning box is an add-on device that alters the sensor signals without adjusting the real software. This can give you some extra power, but it's less accurate and may not suit every engine.

Yes, performance tuning can still retain good fuel economy when it's carried out by a specialist. We can adjust the engine settings so that it produces more torque at lower speeds. This can help the vehicle move better in higher gears, and it often reduces your fuel usage on normal roads.

Performance tuning can affect your insurance because it counts as a modification. Therefore, you must tell your insurer about any tuning work, even if it's carried out safely by a specialist.

Performance tuning can be suitable for towing and heavy loads when it's done correctly. Gee Diesel Services Ltd can adjust your engine so that it produces more torque at lower speeds, which helps the vehicle pull weight more easily. This can lead to smoother acceleration, less strain on the engine and more stable driving.