GETTING READY FOR THE ROAD
I have always had a policy with Discovery 2 and Defenders from Td5 engines onwards, never to attempt to start up the engine until absolutely everything is back together and completed. This comes from the fear of introducing fault codes prior to having the diagnostic kit to read and clear any existing codes.
BLEEDING THE FUEL SYSTEM
Before turning the engine over for the first time, air needs to be bled from the fuel system. On the Td5 this involves turning the ignition on and pressing the throttle pedal to the floor five times. The engine management light will begin to flash, indicating that the bleed sequence has commenced and a distinctive noise will be heard from the fuel system – that of the air being flushed through the system. On the odd time I have not heard this noise, it was due to a fault. One time a bad connection to the in-tank fuel pump; another time due to insufficient fuel in the tank. So, hearing that distinctive low squeal is always a good sign for me. One bleed sequence was all it took – the ignition was turned off, a normal engine starting action followed and the engine roared back to life. Always a fine moment! With the engine running, I next check the operation of the clutch – a slight move forward in first gear, followed by a slight move backwards.
TEST RUN VERDICT
The first test drive was taken gingerly until I confirmed all systems were good. During this, and subsequent early drives, I was looking out for a number of key characteristics. These were the braking system efficiency and balance; the handling, with the new front spring, dampers and Superpro polyurethane suspension bushes; and the engine power, torque and drivability resulting from the combination of all of the upgrades. The brakes were fine from the word go, and they improved with bedding in of the new discs and pads. The Discovery pulled up smoothly and evenly, with the brakes feeling more than up to the job. The transmission brake is also in tip top operating condition and is nicely adjusted for a positive feel.
The combination of the new front spring, dampers and Superpro bushes was a revelation. Often we accept handling that is below par, as we have not really noticed the gradual deterioration. However, by renewing all these components in one go, the transformation is remarkable. The bushes offer a highly compliant ride that is positive but not harsh.
No single engine upgrade on its own will completely transform the performance of a diesel. An upgraded intercooler may help, but full benefit will not be felt without a sympathetic ECU remap to exploit the extra forced air cooling. Likewise, an improved exhaust manifold alone is unlikely to make its presence felt. Andrew Graham at Allisport Ltd explained all of this to me and I have to say that the upgrades I have fitted following his assessment and advice have proved to be exactly what I was aiming for, with overall drivability and flexibility the real goal. The hybrid turbocharger coupled with the larger intercooler, remap and the freer-flowing exhaust manifold have given the Discovery a keen edge in terms of acceleration over a standard vehicle, while the torque characteristic allows for earlier up-changes of gear (and later down-changes) and, crucially for me, a very satisfying towing experience, particularly when at the higher end of the load limit.
Again, my experience of this upgraded Discovery is backed up by the reaction of two other owners. Both had separate cause to borrow my Discovery overnight to get them home (over one-hour drive each) and both returned declaring themselves truly impressed with the performance and fuel economy over their own Discovery 2s.