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John_PWH

Fuel Injector Noise

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I wonder if others have noticed cold engine start-up noises that sound like lifter pinging.

First noticed at 11,000 miles, the dealer identified it as cold fuel injectors at start-up.

It was really noticable last winter, but less so in the SC summer.

Thanks,

JOhn_PWH

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Yeah,

I have 2010 RX250 about 20K miles now. Yes, I heard it too, but it will be gone after 5min.

I took it to lexus dealer and they said it just normal. When the car get cool start, the fuel Injector will work with max speed, that is why you hear the noise, but when the engine get warmer or warm start, the fuel injector will work in normal speed, so you will not heard the noise.

Even the noise does not hurt the engine, but it hurt the owner alot. When you spent more money to buy expensive car like Lexus, you don't expected to heard some noise that the cheaper car don't have it.

That is what I told the service manager.

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I own a 2010 Lexus RX350 with approx 20,000KM and have similar valve lifters' noise problem when the engine cold. I have been driving for about 55 years now and this problem was very prevelant in motors some 25 years ago but I mistakenly thought technology had overcome it. Over the past several years I have owned cheaper vehicles (mainly Honda) and never encountered such engine noise. I agree Lexus must do more than pay lip service to resolving this issue. I would like to see a ground swell of complaints on this matter, which is most annoying especially for those of us living in cooler climes.

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It's not lifter noise. All FI cars I have seen have it (cheap or expensive). It is simply a matter of the ignition computer modifying the timing and firing the injectors for maximum fuel flow.

Since the incoming air is cold, fuel will not atomize as well as it would with warm air. To compensate for this, the fuel mixture is enrichened. The atomization rate is still reduced, but since there is more fuel, enough atomizes to allow the engine to start and run smoothly. In carbureted engines, this is accomplished with a choke. In TBI engines, a cold-start injector is sometimes used. In MPFI engines, the injectors are fired harder. The computer also modifies the timing (as it often does for other reasons).

Try not to let is annoy you. Marvel at the sophistication of the system that is overcoming the physical difficulties of igniting gasoline with freezing air. Look on the bright side--the engine is running! Turn on the radio. Turn up the seat heaters. The heat will be cranking any second now......

I'm not diminishing your complaint. Just pointing out that all cars have the noise, so it might not be effective to complain about it.....

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My '05 F150 makes the same racket when cold. Most fuel injectors are manufactured by just a few subcontractors. Makes sense that the same racket is basically heard across different brands.

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It's not lifter noise. All FI cars I have seen have it (cheap or expensive). It is simply a matter of the ignition computer modifying the timing and firing the injectors for maximum fuel flow.

Since the incoming air is cold, fuel will not atomize as well as it would with warm air. To compensate for this, the fuel mixture is enrichened. The atomization rate is still reduced, but since there is more fuel, enough atomizes to allow the engine to start and run smoothly. In carbureted engines, this is accomplished with a choke. In TBI engines, a cold-start injector is sometimes used. In MPFI engines, the injectors are fired harder. The computer also modifies the timing (as it often does for other reasons).

Try not to let is annoy you. Marvel at the sophistication of the system that is overcoming the physical difficulties of igniting gasoline with freezing air. Look on the bright side--the engine is running! Turn on the radio. Turn up the seat heaters. The heat will be cranking any second now......

I'm not diminishing your complaint. Just pointing out that all cars have the noise, so it might not be effective to complain about it.....

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It's not lifter noise. All FI cars I have seen have it (cheap or expensive). It is simply a matter of the ignition computer modifying the timing and firing the injectors for maximum fuel flow.

Since the incoming air is cold, fuel will not atomize as well as it would with warm air. To compensate for this, the fuel mixture is enrichened. The atomization rate is still reduced, but since there is more fuel, enough atomizes to allow the engine to start and run smoothly. In carbureted engines, this is accomplished with a choke. In TBI engines, a cold-start injector is sometimes used. In MPFI engines, the injectors are fired harder. The computer also modifies the timing (as it often does for other reasons).

Try not to let is annoy you. Marvel at the sophistication of the system that is overcoming the physical difficulties of igniting gasoline with freezing air. Look on the bright side--the engine is running! Turn on the radio. Turn up the seat heaters. The heat will be cranking any second now......

I'm not diminishing your complaint. Just pointing out that all cars have the noise, so it might not be effective to complain about it.....

Bob,

Thanks for the info. BMW must go a step further in sound proofing :-)

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Our does it too. Annoying as I know first hand that Toyota can make an engine that won't rattle, my 06 Tacoma V6 is fuel injected and quiet. You would think their luxury division would be better yet, not so.

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Hi Bob..thanks for your comments,

But my wife has 2010 highlander (v6), I have never heard the knocking sound like I does on my 2010 RX350.

I tested it many times on winter morning, I started the highlander and drove it and try to listen to knocking sound like I heard from my RX, but i did not heard any thing.

I compared between my 2010 highlander and 2010 RX350 (both car has about 20K miles)

Here is list thing I see from my 2010 RX350, but not on highlander.

- knocking sound on cold start (dealer said normal)

- vibrate when you stop on gear. Like when I stop at traffic light, i feel the RX vibrate alot more than normal. I talked to dealer, but they it is normal.

- noise from the back (cargo cover). I remember I paid more $200 to have the cargo cover to get more noise. I took it to dealer changed new one, but still making noise after a month.

So far I am happy with highlander, but really disappointed with my RX. I think lexus build suck car to cost more money. I am thinking to get rid of my RX.

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