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OK, I am 95% sure I have a bad Boost Regulator... I am hearing a chattering noise from the engine and felt uneven acceleration when applying almost full throttle from a stop. I am going to take this to the dealer tomorrow...
I am talking out loud here... but since the MAF is at the intake, I am guessing that the bad Boost Regulator would send surges of air mass into the cylinders for combustion, which would cause knock and make the ECU adjust the KCLV accordingly.
OK, I am 95% sure I have a bad Boost Regulator... I am hearing a chattering noise from the engine and felt uneven acceleration when applying almost full throttle from a stop. I am going to take this to the dealer tomorrow...
I am talking out loud here... but since the MAF is at the intake, I am guessing that the bad Boost Regulator would send surges of air mass into the cylinders for combustion, which would cause knock and make the ECU adjust the KCLV accordingly.
Does that make sense??
Like marbles rattling in a can?
Does it car feel like surging while you are on boost high load?
Timing might be getting pulled back.
Sound like injectors for direct injection.
I though you hear the noise under load.
But if you feel the surging past 3k, ECU is definitely pulling some thing.
A broken boost regulator would pull timing if you're boosting more than the ecu can compensate.
There is a service bulletin for the boost valve, the key description is “surging” after a delay of throttle response. Tell them that and it will be replaced .
regarding knock, there are always false knock from rattles in the engine bay to other factors and small adjustments are made, however if you are seeing knock learn or global adjustment then it means the knock has occurred either at the same rpm and frequency or over a large rpm range for it to make the global adjustment, this is done to prevent engine damage due to bad gas or sudden elevation/temperatures changes.
Sounds like your your issue is with the diverted valve in question which is throwing off the incoming air and effecting fuel ratio/timing.
So I sent my car back to the dealer after running through 3.5 tanks of Chevron. They checked the KCLV value and it was sitting at 19.2; the factory tech noted that this should be greater than 20 still, but was passing. They also duplicated surging while accelerating so they went ahead and replaced the boost regulator.
Anyways, I got home the next day and decided to hook up my new OBDII to check out techstream. I saw that my KCLV decreased to 18.1... I decided to do a couple of drives and record the data to see what happens. My car seems to be knocking quite a bit at high load, low load, high RPM, low RPMs... it seems to be knocking almost randomly. At one point, it drops to 17.5 degrees but does eventually come back up to 19.1.
Any experts want to chime in on this? Is this normal (it doesn't seem like it to me)? Are there any signals I should take a look at specifically?
Do you have any local gas stations with E85 available? If so, wait till your gas tank is empty and then try blending 3-4 gallons of E85 and filling the rest of the tank with 91-93 octane to make an E30 blend. Spend some time to let the ECU accommodate to the higher octane (about a quarter tank worth) and then check to see what your KCLV value is. Mine was previously hovering around 20-22 and after using the E30 blend, my KCLV shot up to 26.
Do you have any local gas stations with E85 available? If so, wait till your gas tank is empty and then try blending 3-4 gallons of E85 and filling the rest of the tank with 91-93 octane to make an E30 blend. Spend some time to let the ECU accommodate to the higher octane (about a quarter tank worth) and then check to see what your KCLV value is. Mine was previously hovering around 20-22 and after using the E30 blend, my KCLV shot up to 26.
At 20-22 and even at 26 deg KCLV, would you say it is normal for the Knock F/B to go beyond -4 regularly under load (20%+)?
At 20-22 and even at 26 deg KCLV, would you say it is normal for the Knock F/B to go beyond -4 regularly under load (20%+)?
Seeing the KFB go to -4 to -5 under mid/heavy load (while the KCLV is at a healthy range) is normal from what I've recorded on my datalogs.
I've observed from real-time viewing that the KCLV the ECU displays will vary depending on the engine load (one for low loads and one for heavier loads). For example, when coasting on the road, the KCLV can read 23 while the KFB is stable at -3. When applying more throttle (i.e. 20+%), the KCLV can immediately jump to a different figure (let's say 25 or 21) without the KFB making any drastic changes. When the KFB starts to creep a digit or two higher or lower than -3, you'll slowly see an incremental change to the KCLV for either the heavy load value and/or the low load value.
Seeing the KFB go to -4 to -5 under mid/heavy load (while the KCLV is at a healthy range) is normal from what I've recorded on my datalogs.
I've observed from real-time viewing that the KCLV the ECU displays will vary depending on the engine load (one for low loads and one for heavier loads). For example, when coasting on the road, the KCLV can read 23 while the KFB is stable at -3. When applying more throttle (i.e. 20+%), the KCLV can immediately jump to a different figure (let's say 25 or 21) without the KFB making any drastic changes. When the KFB starts to creep a digit or two higher or lower than -3, you'll slowly see an incremental change to the KCLV for either the heavy load value and/or the low load value.
Hmm, from my experience, the same KCLV is used for any load condition with the KFB changing under load, which seems opposite of what you are seeing (KCLV changing, KFB constant). What car are you seeing this data from?
Hmm, from my experience, the same KCLV is used for any load condition with the KFB changing under load, which seems opposite of what you are seeing (KCLV changing, KFB constant). What car are you seeing this data from?
This is with the 2nd Gen IS350. Zero-to-Light throttle input will provide one KCLV # and mid/high throttle application will yield a slightly lower or higher KCLV figure before a change in KFB having a gradual effect on the overall KCLV.
The engine has one Knock sensor on the block below the intake runner for cylinder #3.
I think changing fuel is definitely a good first step considering it was Costco gas.
Originally Posted by redspencer
This is with the 2nd Gen IS350. Zero-to-Light throttle input will provide one KCLV # and mid/high throttle application will yield a slightly lower or higher KCLV figure before a change in KFB having a gradual effect on the overall KCLV.
I believe the KCLV does not change based on load for the 3IS due to the ignition timing outlined in the chart above that uses "most retarded timing value" to compensate for different load conditions.
I am bothered that knock is being sensed through low to high loads and resulting in my KCLV to sit between 17-19 degs. In any case, I am bringing the car to service tomorrow to let them figure it out. I am looking to see if I can get this car bought back due to my many trips to the dealer with only 8k miles I've driven on this CPO...
UPDATE: I've been using Costco gas for the past ~6 months and after my 30k service a couple of weeks ago, I saw that my KCLV was still hovering between 17-18 degs. I finally got around to dumping a can of Seafoam into my fuel tank with about 5-6 gallons of gas last Friday and drove pretty hard for the next ~90 miles.
I've been monitoring my KCLV for the past couple of days and it is now at 20 degs! It has been pretty steady and I have not seen it drop below ~19.5. I am guessing the previous owner of the car allowed deposits to build-up in the system due to either regularly using bad fuel or "bad" driving habits (service history shows the car was driven less than 1k miles in the last 9 months of the lease).
The KFB value does seem to act up quite a bit during my drives while I am monitoring, but the KCLV remains around 20. I am planning on replacing my spark plugs soon and I am hoping this will help even more.
UPDATE: I've been using Costco gas for the past ~6 months and after my 30k service a couple of weeks ago, I saw that my KCLV was still hovering between 17-18 degs. I finally got around to dumping a can of Seafoam into my fuel tank with about 5-6 gallons of gas last Friday and drove pretty hard for the next ~90 miles.
I've been monitoring my KCLV for the past couple of days and it is now at 20 degs! It has been pretty steady and I have not seen it drop below ~19.5. I am guessing the previous owner of the car allowed deposits to build-up in the system due to either regularly using bad fuel or "bad" driving habits (service history shows the car was driven less than 1k miles in the last 9 months of the lease).
The KFB value does seem to act up quite a bit during my drives while I am monitoring, but the KCLV remains around 20. I am planning on replacing my spark plugs soon and I am hoping this will help even more.
high load and high rpm will in most cases bring your KCLV up, knock tends to occur more in high load and low rpm situations like on the highway at a steady pace while going up hill.
I would monitor your knock while on cruise control and relatively low rpm.
01-28-19, 07:46 PM
