Phantom knock galore

[Jovan Ceklaj]

Well I'm about at my wits end with this damn car.  I have a pretty bad case of phantom knock that just won't seem to go away.  Almost any throttle position around 2-3k rpm will get me 0 degrees advance.  above that, it's not much better either.  For some reason, in first gear it pulls timing almost immediately.  It's really great! :roll:

Some relevent info

- Base timing at 4 degrees
- I'm using 550 injectors with no dead time compensation  (TMO chip, got it before Jeff O came out with Keydiver chips) with base fuel pressure of 42 psi
- Plugs come out being light brown so tuning doesn't seem to be the issue.
- Stock lifters but they aren't that noisy
- Knock sensor is brand new and tightened to 8 ft-lbs

I'm about ready to just ground out the knock sensor on the firewall and set up some headphones to listen for knock that way while using a wideband.  On the other hand, running this POS of a cliff wouldn't hurt either.  

Any suggestions would be appreciated.

[Andrew Steele]

Jovan and I are in the same boat ...

2G MAF
550's
3" Turbo-back (atleast I am)
S-AFC
t00ned
always 94 octane

Low load, high load, low throttle high throttle, 1st, 2nd or 3rd ... nothing's consistant, 43 (sometimes less) counts of knock around 2-3K rpm + timing retardation.

HELP!

[Martin Raska]

Stop messing around with a stock ecu.  Log, listen, watch the knock sensor, get that wideband going,  watch those plugs and egts, and keep your advance.  You know you want to, what better excuse that being at wits end?.  And we can hook the sensor up to a scope and watch it's actions.

And probably another relavant issue for Jovan is that his combustion chambers were sparkling clean, and they still did this.  Do you guys still get this same knock on C16?  Or maybe you haven't tried it recently enough?

Hopefully the chinese copycat technology market will catch up soon so we can get some $5 incylinder pressure transducers.

[Jovan Ceklaj]

While I have not run it with any leaded gas, I have run it with shitmix of 50/50 Toluene and 94 (around 105 Octane) with no change.  

While getting a standalone is the best solution, it isn't a viable one right now.  Moving down to California is starting to suck up all my money, even after just recently selling my bike.  Unfortunately, the standalone will have to wait a while. :BS:

[Chris Andrews]

What are your afc settings?

[Jovan Ceklaj]

What are your afc settings?

Unusually high.  With a 2g MAS and 550s, my settings past 3k are usually in the +20% region.  Then again, I run about 20 psi on a 14b so I guess it isn't all that unusual.

Low throttle settings are slightly above zero.  In the neighbourhood of 0-5%

[Chris Andrews]

My advice, and by no means do you have to follow it, and I can't say if it will even help...  

1. Just for starters, turn down your boost to a more reasonable 15 (pump gas, right?)
2. a. turn afc down....
2. b. lower base fuel pressure a few points
3. pull the cylinder head and clean the combustion chambers manually

I pull my head once a year, whether it needs it or not.

Your settings for high and low should be somewhere around -10.  With the possible exception of 1000 rpm, 1500rpm low throttle, which should be maybe -5 for idle/ parking lot driveability

I have 650's and I'm -20 across the board on all settings ( -14 at 1000/1500 low throttle.  

I actually suggest running about 11-13 psi on pump gas, and save the 20+psi  insanity for c-16 and the track.......

Timing is more important than boost.    :!:

[Jovan Ceklaj]

The problem really isn't with high load though.  Turning down the boost won't solve issues at low throttle when there is no boost.

Also, my cylinder head was off as recently as 2 months ago.  Piston tops are sparkly clean now.

The high AFC settings have always been a bit wierd for me.  It's definetly a lot higher than what most people with similar mods have.  Then again, every car is different so who's to say that someone else's settings will be right.

[Chris Andrews]

Only suggestions Jovan,   do what you want, and I never said they would solve your problems. All I know is that I don't have PK.

Then again, every car is different so who's to say that someone else's settings will be right.

And then again, you don't know until you try....
Seriously, how hard is it to change your afc settings?  :roll:

But 20 psi on pump is silly.  

If I lived in Vancouver, I'd put my car on Kinetic's dyno and wideband tune it.......

Don't knock (pun intended) my suggestions until you try them.

[Robin Toor]

What are your afc settings?

Unusually high.  With a 2g MAS and 550s, my settings past 3k are usually in the +20% region.  Then again, I run about 20 psi on a 14b so I guess it isn't all that unusual.

Low throttle settings are slightly above zero.  In the neighbourhood of 0-5%

Turn down the boost and lean the piss out of it. +20% fuel is ALOT. You are probably getting rich knock since you have so much fuel going into the motor. Turn the boost down to 15psi, and go down to the negatives in the AFC, that's how my car used to be with a big 16G and 550s, I was -15% pretty much across. You are way to rich. Lean it out until you see real knock, then richen it up a bit and leave it. Throw the wideband in while you are doing it as well, then you will be able to part throttle tune it to 14.5 afr.

With a 16G and 550's running 20psi, I was -15% on the afc, and my fuel pressure wasn't as high as yours either, mine was 38psi. You are way to rich.

[Jovan Ceklaj]

Only suggestions Jovan,   do what you want, and I never said they would solve your problems. All I know is that I don't have PK.

But 20 psi on pump is silly.  

If I lived in Vancouver, I'd put my car on Kinetic's dyno and wideband tune it.......

Don't knock (pun intended) my suggestions until you try them.

Sorry Chris, didn't mean to seem like I was bashing your suggestions.  I most definetly am going to try it, however I'm not going to rule out other options at this point.

Then again, I must stress that my problem is with low throttle when there is no boost.  The problem arises when the TPS shows 10-20% so how much max boost I see is somewhat irrelevant.  

Time to get off my lazy ass and wideband it.

Turn down the boost and lean the piss out of it. +20% fuel is ALOT. You are probably getting rich knock since you have so much fuel going into the motor. Turn the boost down to 15psi, and go down to the negatives in the AFC, that's how my car used to be with a big 16G and 550s, I was -15% pretty much across. You are way to rich. Lean it out until you see real knock, then richen it up a bit and leave it. Throw the wideband in while you are doing it as well, then you will be able to part throttle tune it to 14.5 afr.

With a 16G and 550's running 20psi, I was -15% on the afc, and my fuel pressure wasn't as high as yours either, mine was 38psi. You are way to rich.

Robin giving tuning advice, LOLOLOLOLOL .  Just kidding, I hate you.  

Seriously though, I wish I could turn down my pressure.  My B&M regulator (Read: stock that you can turn up but not down) is no match for the Supra pump.

[Jovan Ceklaj]

So I changed my fuel filter and sure enough, it was absolutely filthy.  I changed it and the car started running disgustingly rich, like undrivable.  Lean it out, to about -5 to -10 and it runs a lot nicer.  Thanks a bunch for the help there Chris, much appreciated.

Unfortunately though, this still hasn't fixed the issues I'm having with my low throttle.  It still pulls timing like a sonofabitch between 10-20% throttle and 2-3k rpm.  I'm thinking this sounds like deadtime compensation.  Any suggestions here?

[Paul Chernoff]

But 20 psi on pump is silly.

hmmm i run 24 on pump, water injection helps with that though  :wink:

[John Hartman]

Jovan, even if your chambers were clean a few months ago, if you have been running really rich for even that short a time(big pressure, big pump AND high SAFC) it will carbon it up quickly.

Take alot of fuel out with the SAFC, I know it goes contrary to what we normally do, but it works. When I first put in upgraded injectors, I was out a ton in my math, so I was at like +5 when I should have been at -15.  Car was HORRIBLE.  Knock, bogging, horrid response, and I got a 15.5 at Mission!

And water injection will work, I betcha.  Not an easy one to do quickly and it will take a few weeks/months to fully steam clean it out, but I immediately saw a drop of half my knock, on the first drive. from 40-43 down to 20-25.

Oh and if you are going to Cali, prepare for horse piss gas.  everyone out there hates it.  Water injection seems to work wonders for the shit gas crowd.

Throwing in a couple of gallons of C-16 WILL tell you if its pk or the real thing.  that shit is magic

remember I've been thru this.  It sucks harsh, and it is frustrating as hell.

[Mitch Delmer]

Sounds like rich knock to me. You said you had the head off?  By chance did you install the CAS 180* off?  I did this in Steves car and it would knock all over the place for no reason.... seems that the INJECTOR timing is based from this, and they were firing on the power stroke and not the intake stroke. It's worth a check.  The two lines on the CAS should line up when the dowel pins on the cams are up and sprockets aligned in the middle, TDC #1.  Hope this helps.