July/August 2021

JULY/AUGUST 2021 AFTERMARKET 35 however would only reach around 3.5 volts (see Fig.3). Also note the significant pressure drop after the engine had stopped. Remember, with the probe still at ground the DRV is still closed there should be no pressure drop. So here is the problem; We have a leak, But only at higher pressure ranges. This exactly corresponds with the drive experience symptoms. Number one golden rule; The fault must match the symptoms. Next steps So, we have a leak but from where? Now we must isolate the high-pressure circuit at strategic points. With the high- pressure steel hoses removed I capped off the rail with cap nuts and ball bearings. Next, I removed the rubber hose from the DRV return circuit and sealing it to prevent leakage. So, when we apply a ground to the DRV we have a blind rail pressure circuit which includes the pump. We also removed the electrical socket from the DRV and fit a dummy valve so the PCM assumes a normal circuit therefore continues to operate the low-pressure priming pump. We then fit a separate test harness to the DRV in order to close the valve. I then conduct a cranking test noting RPS value and any leakage past the closed DRV (see Fig.4). The final scope RPS image (see Fig.5) shows a maximum voltage of 3.8 volts with significant drop in pressure post crank. This rail does not have a mechanical limit valve, and with the absence of any leakage past the closed DRV, we have a faulty HP pump. The total time for the test process was under one hour, avoiding any special tools or component removal for bench testing. The loss of pressure from the pump caused the PCM to increase the DRV control duty until the correction limit was reached, resulting in power drop and loss default. A new pump and steel hoses returned the vehicle to normal performance. Fig. 5 Garages that generally focus on passenger cars are being urged to make sure they can also cater for vans, as the segment continues to grow as partly as a result of the inexorable rise of online shopping. Online sales in the UK are now estimated to be worth £174 billion a year, with the trend increasing during the COVID-19 pandemic. Meanwhile, SMEs and sole trader have also increasingly gotten on the road, while larger fleets have downsized from HGVs to LCVs. All of this means that it is estimated that the van parc has grown by 59% since 2000. Darren Johnson, Group Sales Director at Melett, commented: “The LCV sector represents a huge opportunity for the aftermarket and therefore the supply chain should be working collaboratively to ensure we can maximise this opportunity and plan ahead to capitalise on a market that is expected to continue growing long into the future. “In the UK economy, second and third life vans play a key role, as many SMEs and sole traders use them for their operations. As a result, it’s imperative that the aftermarket is proactive and prepared to service these vehicles as and when necessary.” With this in mind, Melett recently launched an additional eight turbochargers covering the Ford Transit, Mercedes Sprinter, Peugeot Boxer, Citroen Jumper, Fiat Ducato, Peugeot Partner, Citroën Berlingo, and Volkswagen Crafter. For more visit www.melett.com Vans ‘huge opportunity’ for garage sector The LCV sector represents a huge opportunity for the aftermarket... ”