arrowroot

I have a 2016 RX350 FSport with 25000 miles (40000 km) on it. I've noticed three issues with it and am looking for some guidance. I will be bringing it into the dealer soon, but don't want them to just send me home without a resolution...


ISSUE #1: TICKING SOUND COMING FROM ENGINE AREA

When it reached 18000 miles (29000 km) last year (October 2018), I noticed that the engine compartment had a ticking sound coming from it. I didn't notice this sound before that time. When I noticed the sound, I took it to the Lexus dealer and they diagnosed it as a faulty high-pressure fuel pump. They replaced part #23101-0P010.

They road-tested the vehicle and the mechanic reported that the sound was gone. Unfortunately, only a few days after I had the high-pressure fuel pump replaced, the ticking sound came back. I haven't brought the vehicle back to the dealer yet, but will be doing so soon.

The ticking sound seems to be more noticeable on a warm engine. I'm not sure why. I can't tell if the ticking sound is there all the time (or intermittent), but it is certainly more noticeable on a warm engine, when the car is in Drive mode but stopped.

I recorded the following video this week to illustrate the ticking sound. The part located at the top-right of the engine also appears to be vibrating (although the vibration is poorly captured on video).

Video of Ticking Sound: https://drive.google.com/file/d/133s...e2KdRR6mn/view

What could this ticking sound be? Is this normal?


ISSUE #2: UNSTABLE RPM (INTERMITTENT; DOESN'T ALWAYS HAPPEN)

I started to notice this issue after the fuel pump was replaced for Issue #1 above (not sure if it is related).

This happens intermittently. I've captured it on video - the video below was taken on a semi-warm engine, in Drive mode. The AC was off (in case that makes a difference). You can see the RPM needle being very unstable for a bit at the beginning of the video, then it settles down. Sometimes this will happen when the engine is warm, and I'm stopped at a red light. It will be unstable for about 10-20 seconds, then settle down and become stable again.

Video of Unstable RPM: https://drive.google.com/open?id=11N...GLigsRlbYopeQ2

Is this a defect?


ISSUE #3: RPM SURGE / CAR LURCHING FORWARD WHEN TURNING ON AC (INTERMITTENT; DOESN'T ALWAYS HAPPEN)

This is another issue I started to notice after the fuel pump was replaced for Issue #1 above (not sure if it is related).

This issue also happens only sometimes, usually on a cold or semi-cold engine.

The car is in Drive mode but stopped, with my foot on the brake pedal. When I turn on the AC, the car sometimes "jumps" a bit when the AC compressor comes on (I have to put noticeably more pressure on the brake pedal to prevent the car from moving). The RPM will go up by about 300-400 RPM, but the RPM needle is stable and doesn't fluctuate too much after it goes up. When I turn off the AC, the RPM comes down by about 300-400 RPM and I feel like I can put less pressure on the brake pedal to prevent the car from moving.

This issue happens only sometimes - not everytime I turn on the AC, usually on a cold or semi-cold engine. I have not noticed it occurring on a warm engine.

I understand some increase in throttle/RPM is normal on a cold engine, when you turn the AC on. But this increase is substantial enough for me to really have to press harder on the brake pedal to prevent the car from moving forward.

In this video, I turn the AC on & off twice to illustrate the change in RPM and engine noise (can't illustrate the "jumping forward" that the car wants to do every time I turn the AC on): https://drive.google.com/open?id=1Rv...Nieen5QviK4p_2

(AC on @ 0:02; AC off @ 0:12; AC on again @ 0:25 - takes a few seconds for the increase RPM to occur; AC off again @ 0:38).

Again, normal or not? Suspected problem?


Thanks in advance!

technodis

aznkorboi

Mine does number 2 but only sometimes.

Did you try taking it to the dealer and showing them the vids?

ravenuer

Thank God your car only does number 2 sometimes.

(sorry, couldn't resist...)

john341

Ticking sound normal to me( common on all modern engines with direct injection). Regarding the RPM Fluctuation; It could be a leaking vacuum regulator or line. Bad EVAP Valve(Related to fuel pump) and or Failing crankshaft position sensor.

arrowroot

Not yet, but I plan to bring up these issues during my next service.

I didn't notice Issue #2 (unstable RPM) before the fuel pump was replaced in Issue #1 (ticking sound). Not sure if it's related to the fuel pump being replaced.

arrowroot

Ticking sound - I wasn't sure as this is my first direct injection vehicle.
If it's normal, I'm not sure why the dealer would have deemed the cause to be a fuel pump failure and replaced it? (which didn't solve the ticking sound since it came back days later...)

ffmedic75

We just picked up a 2016 Certified Used (not an F-Series) and my wife pointed out the ticking. Very interesting that it's the direct-injection. Our neighbor has a '16 F-Series and we mentioned comparing them upon start-up! Ha! Also interesting the dealer replaced the fuel pump in arrowroot's if the sound is 'normal.'

arrowroot

ffmedic75

I also read about the transmission 'update' that I'll bring up when we take it in for the first service.

ffmedic75

She didn't know. They were stepping out, in their other car, when we chatted them up. I'll find out and update this thread when I have the answer.

pngo

john341

D4-S system can and will work at cold startup to warm the car up quickly for emissions. Plus, the DI injectors are powered by a cam driven pump, which will contribute to more to the noise when there is lower oil flow to the head during low RPM.

arrowroot

The ticking sound is most noticeable on a warm engine, with the car in Drive mode but stopped.

HenryNYC

If the creaking noise (Like a rusty spring being compressed and released) you mention happens when going over SMOOTH bumps/dips on the road which puts load on the rear end of the car.I had the same exact issue just a few weeks back. Took it to the dealer and was diagnosed with bad trailing arm bushings. They had the car a few days due to waiting for parts but after repairs. So far so good. No more creaking sounds. Mine is a 2016 F Sport as well. Still under warranty though so I can't tell yo how much it would been if out and not covered by warranty.