Essex Prestige Vehicle Maintenance

Advanced fault finding saves customer over £3200 parts bill!

Engine lights on and poor vehicle running. This proud, owned from new, Continental GT owner didn’t know what to do when his estimated parts bill was in excess of £3,200. The previous garage had condemned the engine ECU’s and the customer was told to take the vehicle to the dealership for replacement.

So where do you go from here? The customer had found us by recommendation and was happy to wait to get the car booked in for diagnosis.

This 2008 GT had a constant misfire. The first port of call is to do what all garages do nowadays and plug in a scan tool to pull the fault codes.

Cylinder 1 misfire was reported as a permanent fault. On closer inspection it was obvious that the coil for this vehicle had been replaced recently. A quick swap of the coil, spark plug and injector to different cylinders proved both the ignition and fuelling components.

With the engine still misfiring on cylinder 1 it was time to delve deeper into the workings of the engine and its electronics. We first need to prove that the engine was internally sound, to do this we carried out a quick compression test (no, we didn’t pull all 12 plugs and measure the compression manually, thanks to modern tech a compression test can now be done without disassembling anything and in a matter of minutes)!

Tick for compression, no engine rebuild, Phew! However, now it’s starting to look like a possible ECU fault and open wallet surgery! Using a scope, we had a look at the coil outputs to see if the cylinder is trying to fire. Here we can see that only 11 coils were drawing current and that cylinder 1 was constantly missing. With the list of possibilities getting ever shorter and the likelihood of the ECU being at fault increasing there was only a few tests left in our inventory.

Loading the wiring loom and checking for any breaks between the ECU and coil presented no problems. Finally, at last, we had a glimmer of hope and through my own personal experience I could feel the small 1.5mm ECU pin didn’t feel “right”.

A quick call to the dealership prompted the next issue in that the ECU pins were not available seperatly from the complete vehicle wiring loom, but we didn’t stop there. By trawling through Bentley’s farther company VAG’s parts catalogues we came up with a part number for a repair kit. The following day the kits arrived and were fitted before the week end for the customer to enjoy having his pride and joy back!

By analysing a problem 100% and with a depth of knowledge and experience we were able to pinpoint the fault and save the customer a small fortune when fixing his beloved Bentley. Sometimes it really is worth getting a second opinion on tough and difficult diagnosis.

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