Gen1/Gen2 Part throttle/cruise knock Discussion Thread.

[Roddiy]

@btstarcher @Stealth01 @G26


The discussion caught my attention, and it seems that it's not uncommon for your genJuans to get 5+ kr during crusing/part throttling.

I'm pretty sure this doesn't happen to GenPus.

ECU Logic perhaps?

something that crossed my mind was the "smiley" piston design. Maybe that helped?


Discuss.


mention edit: Because knowledge

@phate @rfinkle2 @Daddy Chinkus @driver311
@djuostein

[exentix]

subbing for further investigations. also, hopefully a solution.

[rfinkle2]

The first generation MS3's definitely have more pt kr. I've heard various ideas about why Mazda designed the ignition maps that way, and although I'm not 100% sure, tend to agree with the idea that the ecu is hunting for max fuel economy.

[3Gee Tee]

Would AP solve 100% of KR issues?


Sent from my iPhone using Tapatalk

[Stealth01]

Originally Posted by 3Gee Tee Would AP solve 100% of KR issues? Sent from my iPhone using Tapatalk

I have an AP and custom tune and I still get it.

[PapaSmurf]

With my built motor/fully mounted/no bsd. I see a shit load of PT knock around 3k (like 5.0 or so) when the engine is cold, when its warm its not as much (2.0-3.0)

My fix,

Dont watch knock. lol

I figure I'm putting no stress on the engine anyway, so why let it bother me when I'm cruising.

[NavySailorMS3]

The first thing i noticed when i got my AP was look at my knock and it was fine when i did some logs, but when i was cruising, i shit a brick when i saw i was getting around 5 counts of knock. I was scared of driving it at the time, but after talking with @p057 help told me it was common for the genwon.

[easy]

Originally Posted by PapaSmurf With my built motor/fully mounted/no bsd. I see a shit load of PT knock around 3k (like 5.0 or so) when the engine is cold, when its warm its not as much (2.0-3.0) My fix, Dont watch knock. lol I figure I'm putting no stress on the engine anyway, so why let it bother me when I'm cruising.

your pistons are cold and hasn't expanded yet causing piston slap that gets picked up as KR, you have to warm her up a little before driving and you can set your kr sensor to come on at a hotter coolant temp so its not pulling timing from false knock on a cold motor.

-------------------

aside from that, the last map im running i get no pt knock, even in high gear going up hill crusing ... only kr i got was usually noise from shifting and once in a while small blips of 2-3*, but i think that might be gas related

[skiptowncat]

Little log I did of it, you can see the KR happen right after load/boost drop off and going part throttle. Ignition timing is advancing through the whole thing, it just can't be real knock otherwise we'd see the ignition retarding.
/thread

[breakfstincluded]

subbed, I'll get this cruising 75-80 down I-5 south on my 80 minute trip.

I'll get a very slight less than 1 KR on acceleration after being at steady speed for a while. I lift off and it goes away.

It would make sense to me if it's for fuel economy.

[TiGraySpeed6]

show you're timing tables. this conversation is worthless without solid data points, and the tune will provide these.

I see no pt kr.
edit to add: changes to the kr sensor table too...

[410ms3]

I always get pt knock when i go on my first drive of the day no matter what the weather is like. I always let my car warm up but it seems once it reaches its peak temp i always have pt knock in 5th and 6th gear no matter wut. Anywhere from 5.9 to 7.0. If the motor only partially warmed up it wont do it but once coolant temps reach 175+ it starts. It will only do it a few times and then my pt knock subsides.

[speed14]

I'll ad this as a data point.

Gen pu and i never see the dreaded 6.0 part throttle knock. However, when i am accelerating slowly (not WOT) i will sometimes get .7 to 1.0 KR right around 3k rpm as i get up to speed.

[speed23]

On my 07 speed 3, I would get an event of KR starting at about 5 then decaying to zero as soon as it came up to operating temps everyday. It was only noticeable for me because I drive on the highway so it was always consistant speed, throttle, etc. This consistancy means that the ECU was asking for this.

Interestingly, this does not happen on my 06 speed6.

[410ms3]

Same thing with my 08 ms3. Its like clockwork when i get on the highway. It use to freak me out but im use to it now.

[86AmishMs3]

Don't get this pt knock very often. When it's colder in phoenix...i'll always get it in the same spot about 1mi from home...but I don't let my car warm up so i'm attributing it to possible engine noise (maybe piston slap). It's usually 2-3* then I let off...gone, after that I never get it.

[dooderek]

if its a 2010 genpu then your cursed!!!

[easy]

as per cobb help file:

"This ECU will constantly try to run more ignition advance than is necessary at part throttle conditions. It does this in order
to allow the ECU to detect MBT for each individual vehicle. Once the ECU exceeds MBT, the ECU will remove excess ignition
advance through the Knock Retard function. This is normal and should not concern you, cylinder pressures at part throttle
are not high enough to cause any damage. If consistent Knock Retard is reported or audible detonation is present, you are
welcome to remove ignition advance during part throttle conditions, although your fuel economy may go down during
these conditions."

[kimura]

I used to get the typical PT KR all the time. especially getting on the highway in the morning before the car was fully warmed up. was an everyday occurrence to see 3-5* KR at PT

it went away completely after I did EGR delete, coolant bypass + gasket, TIG, injector seals, VTCS delete and OCC.

I run my DH all the time and I have it set up to alert me whenever I get KR over 1*

no more PT KR. I'm guessing the EGR is the culprit but I really don't know because I did so many mods at once