whee3107

As title states, intermittently will not start. Typically, it will start just fine in the morning on a cold start, but after driving to work the car will sit 2-4 hours and at lunch(ish) will push start and it will crank but not start, press button again (turn off and turn on) and it will crank longer than usual but eventually start. Sometimes it takes 2-3 attempts to start but it eventually will. No check engine lights, has 186,XXX miles, don't recall last plug change, doesn't display any odd behavior..

​​​​​​Took it to the dealer, after having it for a couple of days they were only able to get it to duplicate once. they assure me that the battery checked good (okay, cool). And they want to throw a starter at it, but "aren't sure that will fix the issue.." that's a 1200$ gamble that makes ZERO sense to me.. But, I'll digress. I plan on throwing a battery at it just to rule that out, but wanted some other inputs? i had seen some speculation about a check valve/ fuel rail pressure valve?? Any thoughts?

​​​​​​Thanks

ASE

... unclear with your description ... does the starter crank the engine with each attempt ? .... at normal crank speed ? From your description, sounds like the answer is Yes to both ... but the engine is simply not starting. Did they load test your battery ... or just check the voltage ? Any battery 4+ years old is worth replacing ... so that is a good plan. Even with full voltage, an old battery sometimes does not provide enough current for the fuel pump / control systems to do their thing.

whee3107

yes, starter cranks with each attempt, and with seemingly normal crank speed. On the 2nd/3rd attempt, it will crank for longer than usual and then will start.

I am waiting on a call back from the mechanic who worked the issue and i can ask about the voltage or load test. Battery is between 2-3 years old. I will start with a battery tonight and report back.

GXLUX

That sounds more like a fuel issue to me than a starter issue.
Measuring fuel pressure while starting would tell you if that was the problem.
Next would be the plugs, as you said they could be original. But, that seems like an unlikely possibility for the issues you are describing.
After that there are the sensors that need to have good data to start the car, like airflow and crank position and all that stuff. A good mechanic (and definitely the dealership) can test all of this.

tntcandy

Sounds like a fuel issue, not sure how the 460 engine is build in regards to fuel pressure/pump/accumulator etc

My 1987 560SL is very mechanical, but have fuel injection over the ports (8 injectors)
Its a common issue/known issue for the model to have longer crank start during is the engine is hot.
This is due to not able to hold fuel pressure after you turn off the engine. Cold starts newer a problem as extra fuel is directed to aid the start. When the engine is hot, that feature is disabled.
The cold start procedure hides the lower fuel pressure when car has been parked for a while.
Root cause is the accumulator/fuel pump combo as it can not maintain the fuel pressure and need to "rebuild" it when you start it.
Additionally there is a check valve on the fuel rails that tends to seep, causing same issue.

Again above if not from the 460 engine but an old V8 with mechanical fuel injection over the port, and symptoms are similar.

ROSCOGX470

I agree. I’m having a no start issue but mine seems to be ECU and possibly crankshaft position sensor. I’m doing most of the work with a mechanic friend so certainly confusing for me but a Lexus dealership? That’s just unacceptable. Truck cranks so how is that a starter? Good luck and report back.

armandtoe

My 2016 RX350 68K miles- is doing the same thing. Exactly. The dealer had it for a couple of days after it did it to me twice last Thursday. They gave it back to me saying i must have left something on. They had noticed the battery a little low and put a charger on the 1 year old battery. I said it sounded more like it wasn't getting fuel as it had plenty of crank. Nevertheless, they told me it was ready. The same thing happened to the valet so they kept it a few more days. They determined that i had left the cargo light on, they turned it off and today said i am good to go. I pick it up, go back to work. after a few hours i went back to the car to go to lunch and YOU GUESSED IT!

This time it briefly flashed a verbal charging system malfunction alert. The second try it started and off i went. I have no confidence in this car for my road trip this weekend. (under 500 miles).

TemporaryN

I have the same exact issue. Any updates? Have you figured out what the root cause is?

armandtoe

My dealer discovered that my golf clubs switched on cargo lights in the trunk area. gen 4 RX 350. after that, all good. Good luck to you