kingloose

All

i have a gs430 2001 and i was just told by a friend of mine when he was driving behind me doing about 65 mph i floored the car to go around one clown in a front of me, he said " it was black type of smoke coming out of your exaust and it smelled bad" does anyone know what the hell it could be. sorry i am not a mechanic i just have no clue..

bitkahuna

iTrader: (20)

I've seen that happen on many GS's including mine. Don't sweat it.

SeattleGS400

iTrader: (1)

The bad smell and dark smoke? It's unburned fumes from flooring your car. Most cars, if you floored it, they'd get some sort of black fumes coming from the tail pipes as well as the combustion isn't 100% complete. So long as you're not getting black smoke driving around regularly, your car is just fine.

AlphaJZS

iTrader: (2)

yeah its completely normal I have the same year and model car as you and when I floor it, it smells like...well the closest I can come to describing it is..... a fart..haha

rgarjr

iTrader: (1)

Yeah it should be normal in fact its a good for the engine too do that every now and then too clean up the cylinder and valves.

rominl

iTrader: (4)

yup mine does the same too, as long as it's not black smoke continuously it's good

gserep1

I did not know that the cars made black smoke upon acceleration. I will have to pay closer attention. One question: Is this for stock cars, modified cars, or all cars? I guess I look forward instead of backwards when I drive, because I have never noticed it before.I DO notice a little soot in the exhaust when I look up[ there sometimes. I guess if the injectors didn't flow this much fuel, our cars would not perform as they do.
It probably runs rich momentarily on full throttle. The fuel pressure regulator is definitely working to keep from developing a "lean" condition (which would be very bad).

They are not known for sparkling fuel economy when constantly accelerating (makes sense), but I do get reasonable mileage at saner speeds.

GSEREP1

kingloose

thank you everyone..

and yes it was only when i flored the car.. going about 65 to 100. LEXUS GS430 Rules.. I traded in 540 BMW and Lexus is the *****.

mmarshall

The black smoke you see upon hard acceleration is the oxygen sensor and the engine computer richening up the air fuel mixture to prevent engine damage due to a lean condition with a heavy load.
This computer function is similiar to what the accelerator pumps did back in the old carburator days.
A lean mixture, especially under a heavy engine load, can lead to high cylinder, combustion, and engine temperatures, backfiring, pinging, and spark detonation, which can make the engine oil too thin and cause significant engine damage over time by placing undue stress on the rising pistons in the cylinders. Get knocking, pinging, and detonation hard enough, long enough, and you can kiss your engine good-bye. Although most Lexus products have knock sensors that can deal with 87-octane if they have to, this is one of the reasons WHY Lexus specifies 93-octane gas whenever possible.
If the smoke is VERY black or does not go back to normal when you back off the gas, then have a diagnotic check done on the computer. In fact, overly rich mixtures can be caused by something as simple as a clogged air filter.

bitkahuna

iTrader: (20)

mmarshall, what you say is very interesting to me because I had my SAFC-II tuned by a dyno shop who specifically made the air/fuel less rich from 4000 and up because they said it was too rich. Should I be concerned that they did this, perhaps removing a margin of safety for my engine?