Ive been having a really bad case of the knock blues recently.

For about the last week or so my knock has been going wild. between the 2-4K range, no matter what throttle I give it the knock will skyrocket,

I have to get completely off the gas for it to disappear. I have tried adding fuel and removing it and nothing has helped. Logger doesnt show it being too lean.

Ive found that when the car is warming up the knock isnt there. I have the EGR blocked off, and FPR Solenoid removed as well.

The only thing I havent checked is the coolant temp, but if it was a thermostat problem I would have assumed it would have been running rich all the time or something along those lines. The thermostat is also brand new, replaced during motor swap

Any other ideas?
Thanks
James

Are you hearing any ticking?

Perhaps an exhaust leak at the manifold?

Ive checked again and again for exhaust leaks and didnt find anything.

i find it hard to believe that an exhaust leak would cause this much knock

My on throttle knock went from a full count to a manageable 4-7 with a new knock sensor. Something may actually be wrong like a blown intake mani gasket or worse internals? Try easy stuff like check leaks and clean out the carbon.

Brand new knock sensor as well
and the motor has under 2000k on it so I hope thats not the case.

May not be connected to your problem but.. my knock was caused after my 6bolt swap and new engine because the front left drive-shaft was banging around the back of the block because the metal bracket that holds the shaft managed to come loose.

You may want to check behind the block for missing screws somewhere, because everything MAY look like its on tight, but if there is one screw missing from a bracket or anything similiar, it will start vibrating while driving. This is what happened to me.

Also, just for the sake of trying, go out and retard your cas and go for a drive again.

Well, 2 things happen when the car is cold...

Timing is retarted
Extra (lots) of fuel is squirted.

So Either you are lean (Do you have access to a WB?)
or your base timing is too advanced.

I would say check/reset the base timing and CAS (it couldn't be 180 degrees out of phase could it?)

Retarded the timing a little bit which helped out.
but then I ran into an issue having to pull out more fuel and getting all that timing back.

Looks like I am going to have to find that happy medium, and drop my fuel pressure a little bit as well.

Thanks for the ideas, ill keep you updated

James, give us a breif description of the mods you have and what you are using to "adjust" airflow etc. What is your FP set at, and what base timing are you trying to run?

2.5L G4CS nearly 9.5:1, 60 trim turbo@15psi, 720 injectors with supporting mods, Fuel pressure is at ~28
Stage 3 Keydiver chip, was hoping for 5 degrees base timing but looking like I'll need to run 3.

Have the MAFT but only for the air flow and blow-through, using an SAFC (until the newer DSMLink comes out) for all my tuning.

Just a question. What is the Keydiver chip set at?

If its set for 720cc@37psi (assuming stock FP)then wont you be running a little lean? Esp when you are running only 28psi on your FPR.

Obviously, if you got a 9.5:1 2.5L won't you need more fuel than say a 7.8:1 2.0L?

I'm pretty sure he's set the FP low so that he can add fuel on the SAFC to hopefully end up on a less aggressive timing map.

The chip has the stock timing maps, so it's no doubt going to be too much timing for James' monster of a motor!

Yeah I would say that FP is low (is that vacuum line on or off at idle?)

The Keydiver chip "should" compensate for the injector size, so you should have to worry about being in the wrong fuel map etc.

Keep in mind that with too low of a FP you dont get proper atomization...and when the car is cold the FPS stays closed giving you a higher FP for a while.

I would say leave everything else and bump the FP up and try it out a bit. (I run ~38psi) vacuum line off.

Thats what I thought, so when I first got the motor running I was running stock pressure
But I keep running rich. So I pull out a lot of fuel.

The Keydiver chip was made for 720s at 37psi
so its really confusing me why I need to constantly drop my pressure.

And yes thats 28 with the vac line off

I dont know much about the MAFT but could that be screwing with things? The keydiver chip should compensate for the injector size, but what it the MAFT doing to the airflow signal before it gets to the SAFC and ECU?

I know the MAFT had settings for injector size etc no?

James has his MAF-T set to stock, which should emulate a stock MAF with no airflow adjustments.

That couldn't be further from the truth. The MAF-T has an absolutely infamous history of not being able to simulate a stock MAS/MAF reliably without running -/+10% either way, or whatever ammount you endup with your particular unit.

On my car, I have had knock problems for the longest time and couldnt figure out what the hell was causing it. I had to add alot of fuel to try and compensate but it just didn't do it justice, I was running REALLY rich and alwayd has stupid 2,800-3,200rpm knock EVERYTIME, especially at part throttle, highway driving was painfull because knock would come up every now and then causing me to take my foot off the gas and re-ingage.

My timing was hitting maybe 12-14 degrees MAX at the top of the rev-range, I wouldnt get anymore, and the car was just all-around slow.

I turned back my base timing QUITE-A-BIT, and proceded to adjust extra timing with dsmlink, after the first time of retartding the timing, I took the car for a boot and it just f'ken screamed with never before seen power and ZERO knock.

I would turn your FP backup though, bring it up to 37 or 40, at least in that range. Set your cas to roughly about only 1/3rd advanced and go for a run to see any difference.

Well that just sucks then
But I will say it again, the MAF-T should emulate the stock MAF properly. If it doesn't, then I guess it isn't doing what it's meant to do very well
If only we all lived in Theory, cause it sounds like a wonderful place