In the workshop this week we have been presented with a superb example of the exciting Ford Focus RS which is running a stage 3 tuned 400 bhp engine. This car has been presented to us with a complaint of lacking power and severe lack of boost pressure.
We initially carried out a full serial scan which provided us with no faults in the engine ECU, i decided to carry out a road test whilst data logging the engine data.
I immediately noticed the hesitation and miss fire on the road but interestingly no miss fires were being picked up by the ecu, i suspect the miss fire detect capability had been removed by whoever had remapped THE ECU.
Once i returned to the workshop i decided to remove all the engine covers to expose the ignition components, i then removed the coils and plugs and noticed that the plus fitted were the incorrect heat range for this level of tuning !!
Stage 3 requires heat range 7 not 6 !! I ordered the correct plugs and after a careful visual examination of the coils and noticed signs of tracking i decided to change the whole set.,
I reassembled the vehicle and carried out a second road test !!
Full power was restored which was confirmed by a dyno run which conformed 399 bhp @ the flywheel !