This has been a topic of debated many times on forums / groups about super market fuels over premium brand fuel. What we want to do is give honest facts of what we find when dyno testing and also health checks on modern Diesel engines that customers use the cheaper super market fuels.
The modern Diesel engine now has emissions control systems such as the dpf and egr. The dpf catches and stores soot and uses passive Regen and active Regen cycles to burn the soot off.
Passive Regen Cycle happens when ever the conditions are met such as the dpf reaching a set temp and then the soot build up passively burns off, now usually passive Regen is aimed at taking place when on the motorway and the vehicle at a set speed for a period of time that generates engine and dpf temps.
Active Regen Cycle happens when the engine control unit sees the dpf is at a said soot volume load this is measured by a pressure difference sensor and then the ecu takes over and does a forced Regen Cycle this can be altering the timing, injecting more fuel and the ecu will do a looped active Regen Cycle until the soot volume is lowered. Now if the dpf soot volume doesn't lower you will end up with limp mode and stored Fault codes.
(Note one Fault code that is usually stored is a negative boost deviation as in under boost, many garages and main dealers look at this Fault code and instantly think the turbo is faulty and replace the turbo then only to have same fault, it's due to dpf blocked and back pressure which causes the turbo to struggle to spool)
Ok back to fuel grade... ideally what we need is a cleanest running Diesel engine we can so as to take care of our dpf systems. The cheaper super market fuels we see do not combust as clean as the premium grade diesel and with the cheaper fuel not getting a clean burn generates huge increase in soot volume inside the dpf system.
This week we have seen a T6 2.0TDI-CR 140bhp with just 21k miles that had a blocked dpf causing limp mode and also causing turbo boost pressure faults
We have also seen a 2015 Ford Transit 2.2TDCI Euro5 with 24k Mileage that's already been to Ford for a DPF Pre Vaporiser (injector) and also high dpf soot load, we managed to do a Forced Regen on this and lower the soot volume and advised customer to use premium diesel and report back.
Please anyone with a modern Diesel engine use premium diesel in ur vehicle, yes it might cost a little more at the pump but trust me it's going to save you a huge amount in the long run.
DPF Health Care
1, Use Premium Grade Diesel (also the higher ultimate grade)
2, Limit the short start / stop runs you do
3, Don't let the vehicle sit ticking over
4, Good long runs on the motorway and use a lower gear so the engine is working as in rpm higher so as the engine gets to a higher temp
5, Service the engine regular, ignore the nonsense long life service main dealers push, this is just sales crap to sell more vehicles, every 8-10k Mileage service the engine, oil and filters use genuine spec oil and also genuine OEM filters
We see more and more dpf related issues in the winter months this is due to outside temps much lower and vehicle struggling to get to the desired temp to do a passive Regen Cycle.