Spike of KR only happens sometimes at WOT

[Lex]

Just got back from a 2200 mile road trip through all kinds of temperatures, elevations and conditions. Had a chance to really monitor how the car behaves.

I get very large spikes of KR (6-8) only under certain conditions. Here they are:

1. Car has coolant warmed up already but has only been driven for 10 minutes or less. Getting into some boost here results in KR

2. Car is heat soaked. I have meth injection and an ETS but having the car sit in the california sun and getting on it results in spikes of KR until it cools off. This is not something unexpected and is easy to avoid.

3. What is unexpected is that at times, I would be around 3000 RPM in 5th or 6th and I would stab the throttle (WOT) to quickly pass. Boost would spike to 21-22psi (settles to 15-16psi) and I would get a KR spike of 7 or so. I would back off immediately and do it again. Nothing, no KR spike, nothing larger than 0.4. I would do this repeatedly while on the hwy but could not reproduce it. In other words, happens randomly.

I'm looking for some insight or similar experiences.

Car behaved flawlessly otherwise.

[phailerider]

i think its clear you need to seriously consider building the engine.

[Lex]

Originally Posted by palerider i think its clear you need to seriously consider building the engine.

Isn't that jumping the gun a little?

[ms3077]

Early in the day I took a quick drive for lunch (Pretty much just jumped in the car and went) and my KR warning lit up like 3 times for 3.2, 5.2 and 4.0 KR@partial throttle 4th gear just below 3k (have it set at 1,2&3) Before this the highest I've ever seen was .7 KR. I few minutes ago I took a drive and the highest my KR went to was .4 and it was mostly in vacuum cruising in gear. I think there's a correlation between the car being completely warmed up and KR. Only thing on my car is whats listed in the sig, no power mods yet.

[DaleNixon]

wtf randy?

[GQ_WhiteMS3]

Originally Posted by palerider i think its clear you need to seriously consider building the engine.

Was this sarcasm?

[Hectik1]

Originally Posted by GQ_WhiteMS3 Was this sarcasm?

LOL I hope so.

[Gr33ntumb]

i get same thing

but along with the KR of 5.9, my car makes popcorn popping sounds and stutters

what are your ltft and stft ? i get -15 to -20 at idle .. ( WOT is ~0 )

im guessing im too rich and fukin thing pre-ignites when engine is hot . or leftover fuel ignites ... not sure really what knock is but i sure know what it feels like now

im still under warranty tho and got a CEL just got to let mazda check it out , hope they can figure it out

i also read somewhere that it could be bad compression in one cylinder....

anyway i hope i get a new engine because i guess with having it knock like that i have reduced the lifetime of the engine.,., or if they get er fixed ill probly just sell it

bah this is all blabla, im fuking bored at work and havent drove the car in a few days and just cant wait to get back home and get it looked at. sucks to work on a boat... you wish half your life away .... kinda

[madvillain]

jeeeeesus are you guys serious?! 5.9, 6.0, 8.0?! i thought mine was bad at 0.4-1.1 in vacuum...

[ms3077]

Originally Posted by madvillain jeeeeesus are you guys serious?! 5.9, 6.0, 8.0?! i thought mine was bad at 0.4-1.1 in vacuum...

Yeah, freakin ticking time bombs mang! Lmfao @ Randy's comment!! Epic.

[phillyb]

i've had this happen to me, very rarely...like once or maybe twice. flooring it in fifth, spike high...low 20's or so, and 6.0 knock with an audible ping. never did it again.
this is not partial throttle kr of 6, this is under some load, right?

[phailerider]

Originally Posted by Lex Isn't that jumping the gun a little?

maybe a bit

[Lex]

Originally Posted by phaillyb i've had this happen to me, very rarely...like once or maybe twice. flooring it in fifth, spike high...low 20's or so, and 6.0 knock with an audible ping. never did it again. this is not partial throttle kr of 6, this is under some load, right?

That's exactly what I've experienced. Each time the spike was around 21-22psi right after going WOT. I usually never floor it in that gear but being on the hwy for hours on end I got a chance to play with it some in 5th and 6th. Any idea what it is philly? After this I'd try and reproduce it and I'd get no more than 0.4 KR.

EDIT: Philly are you on the stock pump?

[phillyb]

yeah, stock pump. i don't recall if pressure was low...idk. not enough fuel, lots of air, big kr number, that could make sense.
i really have no idea though

[DaleNixon]

Originally Posted by madvillain jeeeeesus are you guys serious?! 5.9, 6.0, 8.0?! i thought mine was bad at 0.4-1.1 in vacuum...

Haha! Just yesterday I got 7.7 KR in cruise control at -5 vacuum. You're a lucky bastid if you're only seeing up to 1.1.

[Lex]

Originally Posted by phaillyb yeah, stock pump. i don't recall if pressure was low...idk. not enough fuel, lots of air, big kr number, that could make sense. i really have no idea though

How did the "ping" sound like to you? To me it didn't sound like knock. I wonder if it's another noise triggering the knock sensor. The wastegate opening?

[spheed3]

I get the same thing. Usually after being on the highway for 30-40mins then getting off and punching it in fourth gear will always get me 5-7 degrees of KR. I believe this is part of the cars fuel economy strategy by advancing timing as much as possible while cruising. I've found that easing into boost after a cruising will usually result in no KR.

[phillyb]

Originally Posted by Lex How did the "ping" sound like to you? To me it didn't sound like knock. I wonder if it's another noise triggering the knock sensor. The wastegate opening?

mine was knock...you could physically feel the car hesitate for a slight moment

[Lex]

Originally Posted by phaillyb mine was knock...you could physically feel the car hesitate for a slight moment

The stumble you felt is the timing being pulled. So it is the reaction of the car to the noise, not the actual noise or knock. When a car knocks you don't feel any hesitation - you actually don't feel anything.

[94jedi]

Originally Posted by Lex The stumble you felt is the timing being pulled. So it is the reaction of the car to the noise, not the actual noise or knock. When a car knocks you don't feel any hesitation - you actually don't feel anything.

so I wonder what the delay is...from when knock occurs to the point when timing is pulled. does the ecu pull it in anticipation of knock? or is it actually waiting for the noise, then pulls timing?

[Lex]

Originally Posted by 94jedi so I wonder what the delay is...from when knock occurs to the point when timing is pulled. does the ecu pull it in anticipation of knock? or is it actually waiting for the noise, then pulls timing?

It pulls timing once the noise is detected. However, you only feel the stumble once timing is pulled which is the same time your DH will report it.

[phillyb]

ohhh...yeah, retarded timing = pinging...idk the order. that's all i'm witnessing

[KayWhy]

ALL stock cars have KR its a way of life - some have more than others. The best way to combat knock is open up exhaust, colder plugs, colder tstat meth and tune

[Lex]

Bringing this back up because I found something interesting.

These KR spikes have occurred since I installed the CPE rear mount. Turns out that the bolt that goes through the mount and attaches to the engine/tranny binds. As you load the engine, at some point it clicks/moves slightly since there no longer is much play at the rear of the mount. This causes a large spike of KR. This is the reason it happens only sometimes.

Let it sit for a while, it binds again, and releases again causing the KR. The design with the through bolt and nut at the end are more prone to this compared to the stock mount that has the nut WELDED to it.

I greased up the mounting faces of the mount where the long bolt/nut could bind and so far I have yet to reproduce the large KR spike on the hwy or in the morning.

Will keep you posted but this explains a few things:

1. Random KR spikes when getting on the throttle that are not repeatable.
2. KR spikes when getting OFF the throttle and unloading the assembly.
3. KR spike during the first little while of driving in the morning.

This is something that everyone with a non stock mount (or mounts) should look into.

[spheed3]

Very interesting. I'll try greasing mine up as I get the same thing with the same mount.

[Lex]

Originally Posted by spheed3 Very interesting. I'll try greasing mine up as I get the same thing with the same mount.

Remember not to get grease on the bushing on the CPE mount as it doesn't like petroleum products.

[spheed3]

I was gonna try my trusty 3M silicone paste as it's my go to lube for just about everything...yes everything.