BMW 5-Series Touring 530d E61

PART FIVE: Our 530d has an occasional misfire on idle, the radio keeps cutting out and the interior needs a facelift. Andrew Everett gets to work.

Part five: We sort a misfire at idle and a malfunctioning radio.

Old diesels are never cheap to run unless you buy a really old one without a diesel particulate filter (DPF) or get one that’s been fully sorted. Our 134,000-mile BMW 530d has been OK so far, but the fuel economy is still less than great and there are a few niggling issues to resolve.

Parkside Autos in Worksop noticed that the idle had an intermittent misfire. A quick scan with Autologic revealed that injector number six – it would be the one at the back, wouldn’t it? – was out of tolerance and needed to be replaced. The other five still have a fair bit of life left and replacing all six on a car this age would be close to being uneconomical, so it’s just as well that they drop off one at a time.

Replacing the injector involved taking off the inlet manifold. We already had this off in Part Two (May 2019) when we replaced the glow plugs and their

control relay. It had to come off again anyway to replace the control relay, as the Hitachi unit we fitted has failed and Parkside have recommended that we fit a Beru unit, which is an OE part for BMW. You’d think that Japanese parts would be superbly reliable, but Parkside have replaced a few of these Hitachi units. KOYO differential bearings don’t sit well with BMW 1- and 3-Series either and the Ngk-branded NOX sensors for the direct-injection N43 and N53 petrols don’t work as well as the originals. We’ve covered the inlet manifold removal in detail, but we’ll briefly run through it again here for clarity.

A more puzzling problem was why the radio started failing intermittently. You’d be driving along and the sound would just cut out, then come back after a few seconds. I also noticed that, when playing CDS, the sound would cut out and, when it came back on, the CD track would have advanced. Diagnostics couldn’t find any obvious faults, but it was suggested that perhaps the MULF Bluetooth module in the boot was disconnected. We took the car to the experts at ECU Testing in Heanor, who established that the MULF was malfunctioning – it would think there was an incoming phone call and mute the speakers.

Silver to wood

Finally, we replaced the silver interior trim with a set of wood veneer bits. Silver trim is very 2005, so we fitted the dash and console trims in dark wood from a scrap 520i. Be aware, though, that removing the idrive knob is apparently a lot more involved on LCI cars from 2007.