Hey everyone! I'm having a problem with my Prius. It pings under acceleration and it sounds like something metallic is rattling. It only happens when I use 87 and 89 oct. I use 91 premium to reduce the ping however, gas prices are rising and I want to go back to 87. Anyone have any idea what's going on before I take it to a mechanic? There are no warning lights or anything and the ping has been happening for quite some time now.
There is a knock sensor that adjusts the ignition advance to avoid the 'ping' which is the symptom of detonation. If you just run high octane fuel, it would be less bad but you really need to get the knock sensor fixed. Detonation, especially at high power levels can destroy an engine. Bob Wilson
If the knock sensors were defective, would it give a check engine light? are the knock sensors expensive to fix in general? Just waiting to run down the premium gas I put in before taking it in because there is no pinging when premium is used.
The knock sensor works by detecting the high-frequency sounds of detonation. If it fails, it won't 'hear' these sounds and as a result, the car does not retard the spark advance. But it it is not working, there is no signal the sound is not there. I have no idea about the cost to repair. The connector could have fallen off or the detector could be bad. The ambiguity group is larger than can be determined in this forum. You'll have to go out to the car and re-seat the connector. Bob Wilson
