Hi Guys, This one is doing our heads in.Generally around 1,800-2,000 R.P.M.the engine hesitates stationary and on the road in any gear,sometimes it also occurs on the road 2,500-3,000 R.p.m. Along with this it often emits a loud clacking noise which could be mistaken for piston/valve contact.When this occurs stationary puffs of purplish/blue smoke from the exhaust and can feel at the tail pipepops of pressure as if it is firing when exhaust valve open.
No fault codes,component readings,values,
pressures read okay.Found lot of oil in high pressure induction.We replaced depression limiter
valve,took all pipework and intercooler out,cleaned all out,fitted new induction hose with air temp sensor.Put back together,road tested, no issues so handed back to customer.
4 days & later came back doing same thing.No codes, all readings still same.Had brand new injectors july '10.Sent back to supplier(Merlin) test results no faults.put them back,drove it,all okay.Gave back to driver.5 days later came back doing same again.No codes,readings okay.Very dusty interior,took throttle pedal out
and cleaned cotnacts and potentiometer circuits.
Dismissed contaminated fuel(B.P.)due to the fault has disappeared on two occasions. Anyone encountered this or got any suggestions