I have just had my V8 tuned by a reliable and experienced mobile crypton tuner who knows this car and works on other members cars. (If anyone in W.London is interested in using him I am happy to pass on his no).
Anyway having fitted electronic ignition he checked the tuning and emissions. The readings were not right (it was showing 2999 Hydrocarbons and only 4.99% O2 - the former being about 3 times too high and the latter the reverse)
He checked the engine running with each plug removed in turn and found that 4 made no difference at all - there should be a clearly discernible change in engine note when you remove a plug!
He then sprayed the manifold area with carb cleaner and low and behold for a few seconds the engine picked clearly demonstrating that the manifold was not airtight. This is worrying enough but I was even more concerned since only 2 years ago he had diagnosed the same problem and I had the gasket changed.
Question now is whether this is down to failure of the gasket or a crack in the manifold (which I think unlikely given that it was inspected out of engine 2 years ago and the leaks are all over it).
Has anyone ever suffered the same problem (or maybe wondering if this is the cause of similar symptoms) or any advice. Personally I am tempted to write to Unipart but the garage who did the work has changed hands and I have no way of knowing if they used new or old stock.
P6jpe
Anyway having fitted electronic ignition he checked the tuning and emissions. The readings were not right (it was showing 2999 Hydrocarbons and only 4.99% O2 - the former being about 3 times too high and the latter the reverse)
He checked the engine running with each plug removed in turn and found that 4 made no difference at all - there should be a clearly discernible change in engine note when you remove a plug!
He then sprayed the manifold area with carb cleaner and low and behold for a few seconds the engine picked clearly demonstrating that the manifold was not airtight. This is worrying enough but I was even more concerned since only 2 years ago he had diagnosed the same problem and I had the gasket changed.
Question now is whether this is down to failure of the gasket or a crack in the manifold (which I think unlikely given that it was inspected out of engine 2 years ago and the leaks are all over it).
Has anyone ever suffered the same problem (or maybe wondering if this is the cause of similar symptoms) or any advice. Personally I am tempted to write to Unipart but the garage who did the work has changed hands and I have no way of knowing if they used new or old stock.
P6jpe
