I've had a long standing problem with my PZJ70 which has stumped the best workshops and garages, including the Toyota dealership, in my city.
The problem is a thumping noise noise that emanates from the engine. Everybody thought that it was a case of leaking valve(s). So the head and the valves were lapped and everything reassembled but to no avail. The thumping noise persisted.
We also tried another trick to confirm if the valves were still leaking. This was done as follows: A rear wheel was jacked up; that real wheel was turned so that both the intake as well as exhaust valve in a particular cylinder was closed, this was confirmed by removing the head cover; and air was forced in through the glow plug hole by using an air tight adapter; no sound was heard either on the head or the exhaust confirming no leakage; this process was repeated for all cylinders with no leakage.
All other things seem in place. However, there is a plastic socket and plug right above the air filter cleaner box, this device i'm told is an 02 sensor. Since I've run out of all options, could this faulty sensor or problems with the electric system or fuel pump be responsible for the THUMPING noise?
Thanks.
The problem is a thumping noise noise that emanates from the engine. Everybody thought that it was a case of leaking valve(s). So the head and the valves were lapped and everything reassembled but to no avail. The thumping noise persisted.
We also tried another trick to confirm if the valves were still leaking. This was done as follows: A rear wheel was jacked up; that real wheel was turned so that both the intake as well as exhaust valve in a particular cylinder was closed, this was confirmed by removing the head cover; and air was forced in through the glow plug hole by using an air tight adapter; no sound was heard either on the head or the exhaust confirming no leakage; this process was repeated for all cylinders with no leakage.
All other things seem in place. However, there is a plastic socket and plug right above the air filter cleaner box, this device i'm told is an 02 sensor. Since I've run out of all options, could this faulty sensor or problems with the electric system or fuel pump be responsible for the THUMPING noise?
Thanks.