Project Ford Mondeo 2.0 TDCi

MOT & noisy turbo

PART FOUR: The CM Mondeo fails its MOT test on emissions and we suspect its noisy turbocharger is to blame, so with the help of his local garage, Rob Hawkins delves underneath the engine bay to replace it.

We weren’t too surprised when our Mondeo failed the MOT test on its emissions, especially considering the turbocharger had been getting noisier and the hesitation under acceleration indicated that all was not well. We’re still not completely satisfied we’ve fixed all of its problems, but after fitting a replacement turbocharger, the emissions are within limits again, but there’s still a puzzling hesitation from the engine.

It’s not always easy to work out what has been changed or has possibly been tampered with on a project vehicle. Remember the Insignia project car, where we discovered its DPF (diesel particulate filter) had been sliced open and the innards removed? We thought we were faced with the same dilemma on our Mondeo when we tapped the underside of the DPF with a small hammer and thought it sounded a little too hollow. Despite not being able to see any signs of surgery to the outer casing, we cautiously removed it, only to discover the inside was not as empty as we’d suspected it to be. It was a lucky escape because had we needed to replace it with a complete DPF, the ECU may have needed a remap – acommon but illegal modification is to replace the DPF with an empty one and remap the ECU to suit.

One problem that almost prevented an MOT pass concerned the main beam for the nearside headlight. It was nonexistent at the test, and after fitting a new bulb, it still didn’t work. Note that this is the headlight unit that contained lots of condensation when we acquired the vehicle. After discovering there’s only one fuse for the main beam (so that couldn’t have been the cause because the offside was working), Dan Smith at MJ Motors, where the MOT test and repair work was being completed, plugged in his diagnostic equipment and discovered a fault had been raised with the adaptive headlights. This enables the headlights to be adjusted to, in turn, adjust the direction of beam and avoid dazzling. If the electric motors that adjust the headlights fail to work, then something potentially dazzling, such as the main beam, is deactivated. Upon clearing the fault codes, the main beam returned. However, we’ll need to watch this because there’s possibly a problem with the condensation inside the headlight that means this fault could return.

MOT FAILURE