Hey guys,

I dont understand why my car goes stupid with knock. My o2 trims I have tested between 60%-130% for low throttle and nomattter what, around 2500/2700 to 3000 rpms, the knock goes ballistic up into the low 40s. I dont understand it at all and if anyone needs more information I will be of course happy as hell to dish out more to solve this problem which makes me want to sell this pile of shit. For my setup, I have 2gmaf (turned all the way in), 550s, walboro fp, afpr set at 40psi, safc, mmcd program for logging on a palm (which sucks shit btw). If anyone needs anymore information please tell me.

Thanks,
Jacek

What boost are you running? Is it FWD or AWD? Any lifter noise? Intercooler? Engine temps? What spark plugs are you using and what is the gap?

Jacek, you just need to come up here and have it tuned on the dyno. ;)

Change your oil and test it again.

problem is it has done this even before my last oil change (1K miles ago) and i have never been able to understand why. my car is 92 awd with 19c, fmic. I am using ngk plugs (dont remember part #) gapped at .028. the and the temps are normal. car is rather quiet engine wise besides an exhaust leak but piss on that. it doesnt matter if i have my boost set at 8 or 18 at about 18-25% throttle she goes stupid. my

Could be phantom knock. Do another log. When you step on it do you start knocking right away (high counts)? If so, try it again, let off quick, and step on it right away and see if some of it goes away. Do this very quickly. If knock count drops or disapears, it is probly phantom knock caused by too much carbon in the combustion chambers. MCCC would fix that as it did for me.

That is something I have done before to see what is going on and so I will do use the MCCC.

BTW, what is MCCC?? ;)

These threads should help you out Jacek:
http://www.dsmstyle.com/forum/index.php?sh...ic=1362&hl=mccc
http://www.dsmstyle.com/forum/index.php?sh...ic=1317&hl=mccc

Mopar Combustion Chamber Cleaner. It is sold at dodge dealers, maybe others. Got rid of my knock problems.

I did a combustion chamber cleaning and it didnt do a damn thing. :razz2:

Does the knock go away at all, or is it just 40some whenever you are on the gas? what kind of timing do you have, does the car feel fast? My guess is the computer is seeing to much air flow, try taking 5-10% off the afc, see what happens. But it does no seem right to have knock down there, you should not have full boost down that low. Check the knock sensor, ither loose or dead. My car right at 6500rpm goes from no knock to 35ish, but still has 10deg of timing and made good power so I dont worry about it.

~John

does it knock if you hit a big bump? might have somthing rattleing around the engine bay. Just a thought.

the knock goes away. i tried leaning myself out so my trim was into the 120s and it still just hits that spot, takes a dump, then starts to move again. I dont have full boost down there, its when i go past a certain amount of throttle that it hits the knock and when i let off and go past that amount of throttle it just isnt there (or when i begin to boost). No it does not knock when i hit bumps.

What is the high/low throttle settings on your SAFC (the change over point)?

How you tried turning your base timing down to 0 base or lower?

Yes I tried turning my base down to 3 degrees and that didnt help.

Good news, I checked the plug gap/condition today and my gap was a little small and the plugs looked like crap so i changed the plugs and wires and from what I have tested in town is there is no knock. Tomorrow I will see what it does on the highway where the big test is.

Hey guys,
The plugs and wires situation did not solve to problem. Could the EGR valve be making enough noise to cause the situation? It is just an though.

I doubt it.Have you inspected the knock sensor itself, or more importantly the EMI shielding around the harness? Did you make sure the shielding is grounded?

What the hell is the 2g MAF screw? And why did you turn it all the way in?

Its seems to me, your karman counts are fucked up enough as it is(AFC,lower base pressure, 2g MAF, whatever screwed you turned all the way in), you should put back the 1g MAF, set your FP where its supposed to be, and use the AFC only(with mild corrections) and see if this eliminates your problem.I think its either the sensor itself or your load/timing points are just way screwed up.What timing adv are you getting around the point when the knock shoots up?

When was the last time you replaced your fuel filter? A kid on here (boostedgsx or something) was having a similar problem but he would build knock at ~4XXX rpms all the time. I was trying to tune his car and couldn't get around it (doesn't say much though...). He replaced his fuel filter and all was fine. Just a thought...

spring time i changed the filter