Wondering if anyone could help me diagnose a problem with my 2000 lexus gs400. The problem that occurs just started to happen during the last 2 weeks. It only happened once during that time frame. But today it happened again, what happens is when i try to start my car for the first attempt of the day, the car only starts by pumping the gas pedal while cranking over. then a thick white cloud of smoke burst out. But once started everything seems fine and i can drive around with no problems. Just wondering if anybody had any experience with this type of problem or know what is going on. Any help would be appreciated.

 

Could be anything... need more info...mileage, service history. Maybe your just overdue for maintainence, spark plugs, fuel filter, etc...

Pumping the gas pedal while starting, injects way too much fuel... don't do that. You're on the verge of flooding the engine, hence the burst of smoke. When you do flood the car, it's not going to start.... and it can also create another problem totally unrelated to your first problem, making it more difficult to poinpoint.

First "start" of the day is related to the cold start mode... which relies heavily on the coolant temperature sensor and throttlebody or throttle position sensor settings.

Question... Without pumping the gas pedal, will it not start at all? or it has a difficult time starting?

Choritsu-shi

 

Start by cleaning the throttle body.

 

white smoke; coolant leaking into your oil, rubber valve stem seals in the motor have disintegrated, pcv valve (gs300) might need to be changed out, head gasket going out.

I'd get it checked or remove the head myself.

 

Thanks for all the responses .... I'm getting a complete tune up spark plugs, throttle body service etc.... lets see what happens ... will keep status posted...

 

Curious what you found? Also, as someone else asked, would the car not start at all unless you pumped the gas?

 

i dont think the pumping of the gas is really whats letting it start. You mention it only happens when the car has sat for a long time and with out looking at the car myself my best bet would be either; the car is REALLY past due for spark plugs, or my better guess would be that you have an injector or two that are leaking down the fuel pressure as the car sits which means you are starting a flooded engine! White smoke on start up is raw fuel, if it was coolant it would smell sweet and it would happen all the time. By pumping the pedal you are just opening the throttle body which is letting in more air and leaning out the rich condition you have in the cylinders, try just holding the pedal down and see if it starts when this condition happens. Easiest way to prove it's a injector leaking is by putting a fuel pressure guage on and seeing if fuel pressure bleeds down when the car is left sit, it should hold fuel pressure. Again, only a guess with out looking at car myself, i've been a Honda Tech for ten years now. Good luck.

 

Great post!

 

Agreed diagnosing without seeing the car is difficult...or I should say the "smoke".

Smoke on first startup after sitting for long periods can also be attributed to bad valve seals... this allows motor oil to seep past the seals into the combustion chamber. The longer it sits, more oil seeps through and collects. This would be more of a white blue smoke and smells burnt... understandably some may not be able to decipher the difference.

Correctly...Holding the gas pedal down on most all newer cars will turn the fuel off ... doing this won't allow the car to start. On the flipside, if an engine ever is flooded... holding the gas pedal to the floor while cranking will clear it out.

Choritsu-shi