Misfire Diagnosis

Misfires are damaging to engines, Dragon AutoWorks are experts at pinpointing problems


Accurate Misfire Diagnostics

If you've got a suspected misfire on your petrol engine or what feels like a misfire on your diesel engine, We have the tooling & skills to help, plus we've got an excellent track record for resolving misfires efficiently without guesswork & before damage is done to your engine.
Cutting Edge Equipment enables us to tackle even the most difficult of problems so don't give up hope if your local garage has already "changed everything" without resolution, just get in touch today.


Automotive Oscilloscope Analysis

Pico, AVL, Bosch, Fluke, LeCroy Scopes

Dragon has invested in the very latest oscilloscope technology; not only for automotive specific analysis but also the best Lecroy scopes in our electronics laboratory.
How does this help? Scope technology enables us to pinpoint the cause of a misfire much more quickly and in the less obvious cases where a misfire is very hard to detect, a scope can really help.


Pressure Transducers

It's all about making the diagnosis as cost effective as possible. We need to accurately prove what's within spec without labour hours mounting up beyond feasibility. Transducers allow us to perform testing on pressure sensors and cylinder compression in a much more time economic manner.


Dyno Test & Simulation

Simulation of road usage via dyno test enables us to see what's happening in a controlled test environment, letting us find even the most obscure of engine misfires at minimal risk of engine damage.


Smoke Pro Leak Finding

Being able to test for leaks in the intake system and exhaust system helps us to find any pipe or hose damage or even component seal failures that aren't always visable on inspection and only show themselves under the pressure of the smoke travelling through.

We're also able to rule out misfueling and other associated issues by filling the inlet manifold with smoke to find any leaks or problems.


Bosch FSA Analyser

The Bosch FSA Full System Analyser performs emission testing aswell as also testing and simulating a wide range of engine systems and sub systems, providing analysis of the live data for guided fault finding.

It's a fantastic tool to aid in finding a misfire, especially on classic fuelling systems found on older BMW, Mini, Ferrari & Maserati vehicles.


ECU Problems

ECU Testing, ECU Repairs, ECU Replacements

Sometimes a misfire can be caused by a faulty ECU, or by reversing the misfire (ignition coils secondary winding in particular) can damage the ECU meaning that there may be two faults to resolve on a vehicle.

We are unique in that we have never fitted a new engine control unit to any vehicle. We have always been able to repair control units not just for our consumer customers but also for some of the main dealers.
Better still, if we really can't repair the original unit, we can virginise and program a donor unit, saving £s by avoiding a new part.

Common Misfire Questions

  • What can cause a misfire?

    This may be due to a vacuum leak, but it can also be caused by dirty fuel injectors, a weak fuel pump (low fuel pressure) or a faulty fuel pressure regulator. It can also be caused my ignition misfire due to worn or dirty spark plugs, bad spark plug wires, or weak ignition coil.

  • P0300 Diagnostic Code - Random Misfire

    Basically this means that the car's computer has detected that not all of the engine's cylinders are firing properly.
    A P0300 diagnostic code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you that cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are misfiring, nor why.

  • Misfire Symptons

    The engine may be harder to start
    the engine may stumble / hunt, and/or hesitate
    other symptoms may also be present

  • What's the most common cause?

    Air Leaks or worn Spark Plugs, people often put off spark plug renewals for cost reasons

  • Typical Repair Cost

    This really depends on how difficult the problem is to locate and then solve. In most instances it should take no more than an hour to diagnose.
    Diesel engines, which don't really misfire in the traditional sense but it feels the same, can be a little more difficult to diagnose because there are far more variables.

  • Can I drive my car with a misfire?

    No, not unless you want a damaged engine.
    You risk damaging the cylinder(s), cats, dpf or turbo. Be smart and don't ignore the problem, just get it sorted! We can help.