2010 Lexus ES 350 starting difficulty

[ging]

I have 2010 ES 350, and since few days i have occasional problem of starting the car after 3-4 attempts. Worst is its is not happening immediately and only happen after 8-10 hours of stop. And also it happen 4 out of 10 times and not always. I went to few mechanic and they asked me to leave the car (which I can't) to diagnose it. Any advise here will be very nice to plan my car maintenance and my office lift.

[harryd]

When have you changed the battery last time? these funny issue usually happen coz of electric and first thing to doubt is battery then going any further. does yoiur battery comes with some health indicator like in inco and solite glass eye is there to peep the battery health = green or dead=white.

[treks]

Hi ging,

I'd like to help you out with this problem, but I need more information, so can you answer these questions?

1. Does the engine crank at normal speed?
2. Do you see any warning lights on the dashboard when it won't start?
3. Did you replace the battery recently?
4. Do you have a smart key, and when last did you replace the battery in the key?
5. Does the problem only happen when the car was parked in the sun?
6. Does the car run normally once it does start?
7. Does it run normally all of the time?
8. Does the idling fluctuate, or does it idle unevenly?
9. Has the fuel consumption changed at all- does it now use more fuel than before?
10. Does it take three or four attempts to start it when it won't start, and do you smell fuel when it does not want to start?
11. How long do you crank the engine for when you try to start it?

There are more questions, but these should do for now.

[ging]

Thanks treks,

Please find my answers below:

1. Does the engine crank at normal speed? Yes
2. Do you see any warning lights on the dashboard when it won't start? No
3. Did you replace the battery recently? No, 10-12 months back
4. Do you have a smart key, and when last did you replace the battery in the key? Yes, and battery changed long ago, but if its weak it fails completely and dont behave like this.
5. Does the problem only happen when the car was parked in the sun? No, it's always under shade.
6. Does the car run normally once it does start? Yes
7. Does it run normally all of the time? Yes
8. Does the idling fluctuate, or does it idle unevenly? No
9. Has the fuel consumption changed at all- does it now use more fuel than before? Don't know exactly but its more or less same as before
10. Does it take three or four attempts to start it when it won't start, and do you smell fuel when it does not want to start? Yes 3-4 cranking, but no smell.
11. How long do you crank the engine for when you try to start it? Only once, but when it delays it cranks for 4-5 times in one go before starting. Otherwise half crank it starts daily.

[Danny]

Can you open your engine air filter and clean it properly with pressurize air and if it's too dirty, clogged and become dark in color better to change so that your engine can breathe better. I think it's your air filter is not able to suck enough air as anyways you park under the shade or in closed underground parking. My two cents in taking an educated guess with above information.

[kadar]

its sure not battery, as that will have multiple cranbking and not only long crank.

one long crank means good battery.

[treks]

Hi ging,

Based on your replies to my questions, Intermittent fuel pressure drops is the most likely cause of the problem.

It is likely that either the fuel pressure regulator, or the non-return valve in the fuel filter is defective, allowing the fuel pressure to drop to below the level required for the injectors to work.

If the presssure regulator sometimes stitck partially open, it will allow the fuel in the system to drain back to the tank, and it would typically take 4-5 revolutions of the engine for the pump to pressurise the system sufficiently for the injectors to work.

The fuel pump delivers fuel at a constant rate and pressure, and the job of the pressure regulator is to control the pressure when demand for fuel drops, such as when you decellerate, and the engine speed drops. So even if the pressure regulator is defective, the engine will run normally, since the fuel pressure keeps it open, and more than 98% of the fuel that is delivered to the system is returned to the tank via the regulator.

It is entirely possible that when you switch off the engine, the regulator sometimes does not close all way, allowing the residual pressure to drop too low for the injectors to work. This will not trigger a warning light on start-up, since the fuel pump runs when you crank the engine.

2.) The non-return valve in the fuel filter could also be defective, causing exactly the same problem.

Other possible causes could include intermittent failure the crank angle sensor, or cam shaft position sensors. This is unlikely though, but not impossible. Thus, my advice would be to first replace the fuel filter, then to have the fuel pressure regulator and its control system checked out if replacing the filter does not solve the problem.