808-lexus

for the past year, there was a rattling sound coming from the engine when i accelerated quickly or just simply accelerated up a hill. yesterday, i was talking with someone and we found that it was detonation!!! in the manual, it recommends premium unleaded, so i'm not sure if what would be now regular was premium back in 1990 when the car was made. this week, i'm going to upgrade the fuel from 89 to 91 and try to make it detonate.

what would be the major damage it would have done if it was detonating for possibly longer than a year?

CptnTonus

Don't EVER try to many an engine detonate, that's simply a stupid idea. Octane levels in gas haven't changed much over the years, definitely not since these cars were brand new. If you've been putting 89 octane in your car, that could make it ping. Pinging is what you were hearing, which isn't necessary harmful to an engine, but it's definitely not great either. Prolonged detonation can put pre-mature wear on the rod bearings, piston rings, cylinder walls, pretty much everything. If you're really concerned about it, do a compression test on your engine to see if there is piston damage.

I would suggest doing a complete tune-up on the car if you haven't done one in a while. Replace everything that's within reach. Fuel Filter, Air filter, Caps, Rotors, Plugs, Wires. It's also not a bad idea to use some kind of combustion chamber cleaner like Seafoam to clean things out. It's also a good idea to take off your throttle body and clean it. After doing that, use premium fuel exclusively. It says "Premium Unleaded Only" on your gas gauge, that's not a suggestion, it's a requirement. The 1UZ is 10:1 compression, that's not something I'd wanna use low-quality fuel for.

sonyman

The manual specifies 91 octane, and you should use nothing less on a day-to-day basis. One factor that may be aggrevating your condition is carbon build-up. If I were you, I would run a can of BG44k or an equally strong cleaner through the gas tank, which will hopefully make a dent in any carbon present in your engine. A dose of seafoam through a vacuum line wouldn't hurt either.

GRAND_LS 4

iTrader: (2)

I suggest only using 91 or 93 where available for your LS. The savings arent worth it with the way the ECU is programmed.


By the way, have a quick look at this thread:

https://www.clublexus.com/forums/sho...d.php?t=247695