real or phantom knock... you decide.

[Coldandafraid]

got my keydiver chip installed, and I have to say, I love the knock gauge. I also have to say... I hate that my car is knocking (randomly) during easy acceleration.

My low fuel trims are perfect. Yet, during very mild acceleration (20% throttle), only after warmed up, about half the time my knock gauge goes through the roof and timing drops. The rest of the time, very nice acceleration, no knock.

Good news, I now know why my car has "good days" and "bad days", and I definitally recommend the keydiver chip to anyone with a 2G for the knock gauge feature alone.

So, are we all in agreement that this is phantom knock? I dont have the classic symptoms of knock at idle, only during mild acceleration. Also, if I see knock, and I let off the gas and try again, half the time the knock will stop and I can accelerate as usual.

 

[JiveMasterT]

my car has the same problem, but i dont have a new chip. ive been looking for an answer for the longest time. so if anyone knows... tell us!

 

[doug]

I vote for phantom knock. Unless it's "rich knock" which even the very existence of is debatable.

 

[L2RTSiAWD]

Moved to tuning talk

 

[90AWDTalon]

got my keydiver chip installed, and I have to say, I love the knock gauge. I also have to say... I hate that my car is knocking (randomly) during easy acceleration.

My low fuel trims are perfect. Yet, during very mild acceleration (20% throttle), only after warmed up, about half the time my knock gauge goes through the roof and timing drops. The rest of the time, very nice acceleration, no knock.

Good news, I now know why my car has "good days" and "bad days", and I definitally recommend the keydiver chip to anyone with a 2G for the knock gauge feature alone.

So, are we all in agreement that this is phantom knock? I dont have the classic symptoms of knock at idle, only during mild acceleration. Also, if I see knock, and I let off the gas and try again, half the time the knock will stop and I can accelerate as usual.

I'm having the same problem. Ton's of knock at mild exceleration, none at idle or WOT. Seems to happens somewhat randomly. I vote phantom knock.

 

[Coldandafraid]

well, I dont trust my aftermarket O2 sensor, so I am getting a mitsu one. And, a new knock sensor just to be sure. And, Im wondering if I should get a fuel pressure gauge, and an fpr as well.

No amount of fuel will make the knock go away. It will still knock randomly during mild acceleration. Also, if I see knock, but keep the throttle constant eventually the knock will go away and the car will pick back up again.

 

[HighPSI TSi Guy]

real phantom knock is rare under accel...

 

[Coldandafraid]

yeah... that is what I was thinking. But my trims are right on, at least at low throttle... and that is where this strange knocking is at.

Its random... 1 out of every 4 accelerations it will knock. Then, if I let off the gas and try again, it will stop knocking. Or, I can accelerate constantly, all the while its knocking, and then out of the blue it will stop knocking.

 

[doug]

real phantom knock

Yeah, I hate that fake phantom knock.

 

[Coldandafraid]

fake phantom knock... thats like a double negative... so it must be "real" knock.

 

[HighPSI TSi Guy]

yeah... that is what I was thinking. But my trims are right on, at least at low throttle... and that is where this strange knocking is at.

Its random... 1 out of every 4 accelerations it will knock. Then, if I let off the gas and try again, it will stop knocking. Or, I can accelerate constantly, all the while its knocking, and then out of the blue it will stop knocking.

trims mean nothing under hi throttle. it sounds kinda like tip in to me which is a bi*** sometimes. what are your mods?

 

[Coldandafraid]

trims mean nothing under hi throttle. it sounds kinda like tip in to me which is a bi*** sometimes. what are your mods?

I know... and I have not even gotten into high throttle yet... this knock is during low throttle, even during perfectly balanced trims.

what is "tip in"?

 

[HighPSI TSi Guy]

tip in is a quick drastic change in throttle that can sometimes cause knock that is difficult to tune out. if you're knocking like that at part throttle i'd have to say check your knock sensor, or you may have a fuel delivery issue

 

[Coldandafraid]

Ah... ok, well its definitally NOT a drastic change in throttle. It can start knocking if I just crack the throttle from a roll.

I have a new knock sensor coming. And as for the fuel, the logger still says that I am good while knocking, but I am getting a new o2 sensor anyways... and was wondering if an apfr would be a wise thing to have.

 

[Coldandafraid]

One thing I noticed, that I may just be imagining...

During the accelerations, when it doesnt knock, my trims balance. But when it knocks, it seems like the short term trim is about 5% less that what it was when it doesnt knock. Its like the ecu, for some reason, decides not to correct as much that time. So I let off, and try again, and then it doesnt knock. Then again, this could all be in my head as I search for an answer.

Another thing, if I let off, but not all the way, and then get on it again, it continues to knock. Like, I have to completely close the TB and then open it again for the knock to go away...

very odd...

 

[Coldandafraid]

Another update.

It runs virtually knock free on the first drive of the day... doesnt even matter how long I drive it for.

But the next time I start the car, and every time after that until the next morning, it drives with the previously described knocking behaviour.

 

[reyvin]

I think I've got the same thing going on. So what's the final verdict on fixing this? Anyone?

 

[moonstation2000]

i've been watching my car behave in this way since i got my logger. you will find it's worse in hot weather, try logging air temps too and you'll see. first drive may show less knock because it's cooler out.
my ig lifters were really bad until i got this tip, and i'm saying this trying not to sound like an idiot (because this is my secret shame) but i used v-max (oil & fuel additive).
the first time i put it in it completely cured my knock. for one day.
the next time (they give you about 4 bottles) it lasted for a week, the last time lasted throughout winter, which always improves things anyway.
summer came and my knock was much better than last year.
2 weeks ago i switched to 3g lifters. i had bad knock for a couple days, now they're about the same as the vmax cleaned ig lifters.
next oil change the vmax goes back in, along with a heat shield for the air filter, my intake temps even on the highway are about 15-20 deg higher than ambient, in thaffic i routinely see 105-120 degrees, and it's not even that hot out yet.

 

[my_gst95]

Might wanna try swapping with a friends working MAF, and also try swapping ECU's. I know the 2g ecu's don't have caps, but I do know that on my 90's chipped ecu, I recently changed out to a friends TMO'd ecu, and it seems to have fixed the high counts of knock on light acceleration. Another thing to check would be your fuel filter if you haven't changed it recently. My car was running leaner then normal on partial throttle, due to a fouled filter, and thus causing knock. You can tell also by looking at your spark plugs, and if each plug looks leaner and leaner the further you get from filter (ie plug 1 is leaner then 2, 2 is leaner then 3, etc), then it would be a good idea to change it out. Good luck finding it, partial throttle knock SUX.

my_gst95

 

[Coldandafraid]

I have a GM maf... so air temp has nothing to do with it for me.

However, I did a penzoil engine flush the last time I changed my oil, and for about 3 weeks, no (phantom) knock at all.. ever. Then after that, the (phantom) knock started slowly coming back on the odd drive, but still no where near as bad. So... penzoil engine flush for me from now on every oil change.

 

[1fast97gsx]

Maybe you all sucked in birds through your turbos? What turbos are you guys running? :laugh:

 

[kpt4321]

If anything with oil changed it, then it's probably not real knock. Sounds like a mechanical noise.

If any of you still have the old HLA's ("lifters") then swap them out now. It's totally pointless to troubleshoot phantom knock problems if you have clackers in there.

I had a nasty phantom knock problem in my car; it was undoubtedly not real knock, there is simple no way it could have been. I'm modifying fuel and timing maps right at the ECU, so I was able to make everything VERY conservative. No changes. It wasn't real knock.

Now I programmed the ECU to just zero the knock count out at very low loads. It's freaking nice.