|
Let me preface this by saying that I know absolutely nothing about a 1984 turbo brick.
Having said that, I know a little about cars in general, and they all work on pretty much the same principles.
Any engine with a turbo should have a knock sensor somewhere on the block. It works like a little contact microphone. When it detects a knock, it retards the timing until the knock goes away. I would look for the knock sensor and check/clean all the electrical connectors from it to the ignition timing control. If the connectors are clean, consider buying a new sensor on-line and trying it before paying for a mechanic diagnosis.
If 1984 uses a vacuum diaphram to regard the timing (looks like a conventional vacuum timing advance, but pulls the other direction), check that the vacuum hose is intact and that the diaphram has not failed and started leaking.
If you have a timing light, tap on the block with a hammer somewhere near the knock sensor. If the timing doesn't immediately retard in response to the tapping, you know the problem is somewhere between the sensor and the distributor.
Whenever any brick starts detonating, you should check to make sure that the air door in your air filter housing is closing when the car gets warm. If it hangs open, you are pulling heated air in to the air filter of a hot engine, and that will cause detonation.
If the spark plug heat range is too 'hot', the spark plug tips will not dissapate heat fast enough and can get red hot. This will cause pre-ignition, which is indistinguishable from detonation so far as the drivers is concerned.
Finally, corrosion inside the head that disrupts water flow around the valves and spark plug can lead to hot spots that cause pre-ignition. I once worked on a 64 Mercedes that had never had its coolant replaced in 15 years. Corrosion attacked the water guides in the aluminum head and resulted in hot spots.
|
