Spark knock during freeway passing maneuver
08-25-15, 08:19 AM
#1
Advanced
Thread Starter
Spark knock during freeway passing maneuver
Even on 93 octane, I hear a burst of spark knock for a brief second when I go WOT at freeway speeds. Is this common?
08-25-15, 10:38 AM
#3
Lexus Fanatic
08-25-15, 03:32 PM
#5
I'm not sure what spark knock is, but every once in a while when I accelerate from between 0 and 20 to 60-80+ WOT, I'll get the flashing the check engine light and Check VSC message on the DIS. Everything ends up clearing up though once I come back down to around 20 mph.
Originally I had done a run from 60 to triple digits when the issue first surfaced. That time the lights stayed on and didn't turn off. I used Carista to clear the codes (I use cruise control all the time and with VSC not working, cruise control doesn't either). And now I have the lights sporadically show up. I'm not sure if I can reliably reproduce the symptoms since I don't do any hard accelerations anymore due to the flashing engine light which means that the engine is knocking and me wanting to prevent any further damage to the engine.
I'll definitely be having my dealer take a look into this on my next service which is due in the next 800 miles.
Originally I had done a run from 60 to triple digits when the issue first surfaced. That time the lights stayed on and didn't turn off. I used Carista to clear the codes (I use cruise control all the time and with VSC not working, cruise control doesn't either). And now I have the lights sporadically show up. I'm not sure if I can reliably reproduce the symptoms since I don't do any hard accelerations anymore due to the flashing engine light which means that the engine is knocking and me wanting to prevent any further damage to the engine.
I'll definitely be having my dealer take a look into this on my next service which is due in the next 800 miles.
08-25-15, 04:38 PM
#7
On the flip side, all my typical day to day driving is around town and less than 5 miles a day total so I never see the flashing light. I'll be setting up an appointment for one of these up coming weekends, though, to take it in.
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08-25-15, 06:55 PM
#8
Pole Position
I'd say more info is needed here to figure what it is. You hear spark knock upon WOT? How can you hear anything on these cars? Windows down? And with this noise, is there a performance problem? Does it stumble or misfire?
As for flashing check engine lights, those are cat damaging warnings, which means raw fuel is being dumped into the cats where they'll heat up and actually melt the converter. It's the manufacturers way of telling you...this is a problem that will cost you a lot of money if you don't get it fixed. Usually it's a fuel injector or coil problem causing the fuel to go unburned in the cylinder.
As for flashing check engine lights, those are cat damaging warnings, which means raw fuel is being dumped into the cats where they'll heat up and actually melt the converter. It's the manufacturers way of telling you...this is a problem that will cost you a lot of money if you don't get it fixed. Usually it's a fuel injector or coil problem causing the fuel to go unburned in the cylinder.
08-26-15, 11:54 AM
#9
I'd say more info is needed here to figure what it is. You hear spark knock upon WOT? How can you hear anything on these cars? Windows down? And with this noise, is there a performance problem? Does it stumble or misfire?
As for flashing check engine lights, those are cat damaging warnings, which means raw fuel is being dumped into the cats where they'll heat up and actually melt the converter. It's the manufacturers way of telling you...this is a problem that will cost you a lot of money if you don't get it fixed. Usually it's a fuel injector or coil problem causing the fuel to go unburned in the cylinder.
As for flashing check engine lights, those are cat damaging warnings, which means raw fuel is being dumped into the cats where they'll heat up and actually melt the converter. It's the manufacturers way of telling you...this is a problem that will cost you a lot of money if you don't get it fixed. Usually it's a fuel injector or coil problem causing the fuel to go unburned in the cylinder.
I haven't done WOT since then and everything has been normal.
OP's case might be completely different.
08-26-15, 02:04 PM
#10
Advanced
Thread Starter
Windows up, punch it at 75 and it knocks briefly. No performance impact or check engine light. It has 54k and could use new plugs, so I'll try changing them next (without leaving any small fasteners laying on the rocker covers, of course ;-p).
08-27-15, 11:03 AM
#11
Knock sensors are there to prevent this, when "hear" knocking they adjust timing, fuel, air intake, etc to prevent it. Sounds like you have some kind of sensor malfunction Should be an easy fix after hooking it up to a scan tool.
If there is no Lexus dealership close to you, a Toyota dealer can do warranty work for you. I've done it.
If there is no Lexus dealership close to you, a Toyota dealer can do warranty work for you. I've done it.
08-27-15, 04:51 PM
#12
Pole Position
In my case, I'm not sure about the OP, I hear nothing different. The car keeps on accelerating, it doesn't really feel any different. The check engine light will flash (VSC message will come up, traction and some other lights will come on also) and stop flashing once I'm done accelerating and then (at least the last time I did this) once I dropped to around 20mph every thing went back to normal. All lights went out.
I haven't done WOT since then and everything has been normal.
OP's case might be completely different.
I haven't done WOT since then and everything has been normal.
OP's case might be completely different.
08-28-15, 07:23 AM
#13
Flashing engine light would suggest it's knocking under heaving acceleration but I'm not sure why VSC, traction control, and the other lights would come on.
08-28-15, 08:08 AM
#14
I would get your electrical system checked out. Voltage fluctuation especially with a failing regulator will cause all sorts of havoc. I had something similar in regard to idiot lights randomly coming on on my other car. It turns out that I blew the regulator by revving the engine higher then what the alternator was rated at.
08-28-15, 08:27 AM
#15
I would get your electrical system checked out. Voltage fluctuation especially with a failing regulator will cause all sorts of havoc. I had something similar in regard to idiot lights randomly coming on on my other car. It turns out that I blew the regulator by revving the engine higher then what the alternator was rated at.