Date: 16/12/2009
Vehicle: Rover 75
Year of manufacture: 2001
Engine: 1.8 16v (K16)
Symptoms: Vehicle refusing to start
Duration: 1/2 Day
Customer Brief:
The customer bought this car to our attention after being recovered by a well known recovery company to his local garage after having some engine work carried out. The vehicle was running fine the day before but just refused to start the morning after. The recovery agent diagnosed the issue as low fuel pressure but could not fix the vehicle and advised the customer to get a new fuel pump fitted at his local garage (Which he did at a cost of £220 for the fuel pump alone). This didn’t remedy the situation and so the customer turned to us for help tracing the fault.
Day 1 – Call out & Inspection:The car wouldn’t start as advised but we like to make sure we know where we stand so all the basics were checked out first just in case they’d been missed. Diagnostics were connected and all engine and immobiliser systems were checked, found to be in order and the injectors appeared to be working fine on the oscilloscope (so far, so good). The engine had a strong spark and thankfully would run fine when “easy-start” was added to the throttle body (hurrah); the problem was obviously fuel supply related and as originally diagnosed by the recovery firm, the fuel pressure was found to be too low to supply the injectors with fuel.
Moving towards the rear of the car and under the rear seat bench the fuel pump wiring was next to be checked but all seemed fine as the pump was getting good power and operating as it should. Good news seeing as the customer had but the day before had the fuel pump replaced for a brand new unit at a cost of £220 only to find the car still refused to start due to what appeared to be nothing more than a simple lack of fuel pressure at the fuel rail.
The Rover 75 uses a two part fuel pump/filter system and the filter was the next item needing to be checked being the next component in the fuel line – and it was here problems were found as the filter housing was in two parts (“Fuel Filter Seperation”); one part, the main body, floating in the bottom of the tank and the other, the sealing cap/lid, still attached to the top of the tank head and fuel “flow” line (not ideal). Its not clear why but for some reason the fuel filter design was updated by MG-Rover around 2001 to be a two part setup which comprised of a base (which holds the paper filter element) and a screw-on cap/lid with a “flow out” line direct to the fuel rail. From a servicing point of view the new design made accessing and changing the fuel filter very easy for the servicing technician but they could also problematic in two ways. The first is that these filtes though basic in design can be re-assembled incorrectly trapping or just simply not replacing the sealing O-ring which allows fuel to pass between the two parts at there joint. The second and more common issue with this new filter setup is where the lid unscrews itself over time causing the two parts to separate inside the fuel tank which in turn leads to a 100% loss of fuel pressure. It is worth noting that K16 powered Rover 75′s produced pre-2001 used a different filter setup and so didn’t suffer with this “Fuel Filter Seperation” issue. For K16 powered cars produced post-2001 “Fuel Filter Seperation” is possibly the biggest cause of fuel pressure loss and a little known fix is available from MG-Rover/X-Part in the form of a cheap but effective orange plastic clip. When this orange plastic clip is fitted to a correctly assembled fuel filter assembly it prevents the gradual unwinding and eventual separation of the two parts that make up the assembly and so stops the failure.
This orange clip (Part number WJC000230) retails at £5.43 inclusive of VAT and is available from your local X-Part dealership or online from Rimmer Brothers who are a trusted and official MG-Rover parts reseller in the UK. After fishing around in the bottom of the fuel tank for the remains of the filter housing and the all important rubber O-ring that seals the unit it was reassembled and refitted along with the orange plastic clip. Instantly fuel pressure was restored which was once again measured at the fuel rail and seen to be back to normal (3.5-4.4 Bar according to the technical literature) and the vehicle instantly restarted as is there were no issue at all.
Conclusion:Unfortunately, this was an unnecessarily costly exercise for the customer who had purchased an expensive fuel pump that wasn’t needed on the advice of the recovery company who hadn’t fully investigated the issue. Hopefully this case study will help owners or garages in a similar situation from making a similar mistake and help to resolve the actual issue by buying the cheaper orange plastic clip fix.
Rover 75 Connoisseur, 1.8 16v
