wouldn't the cylinder show some too? there are signs of that happening on cylinder 3...the walls of the valve cover in that cylinder are white. all the paint is gone. that was what prompted me to change all the injectors. that cylinder looks fine though, as far as the piston and the plug.

it's the number 1 that's clean.

You say you have been babying the car. Maybe your only pushing coolant under boost which is why your coolant levels have not changed.

I haven't been babying the car at all

BUMP... $5 in EVOM gratitude money for anyone that can tell me why I've got one clean cylinder.

Did you ever try race gas or a different knock sensor?

waiting on the knock sensor, and tactrix cables to come in. as soon as my cable gets here and I can start logging again, I'm going to give race gas a try.

well, finally got my tactrix cable in, so i'll be able to do some new logs today. I'll be filling up on race gas as soon as I run some of the gas out of my tank, then flash back to my old tune and see if the knock goes away.

okay, update. I tried a couple things.

First I ran a couple logs with the tune that's currently on the car. both 3rd gear pulls. then I ran a log of the car just sitting still and revving.

then, I flashed back to the more aggressive tune that was on the car at the time that the knocking first started, and I added the race gas. about 5 gallons of 93 in the tank, and I added 5 gallons of 109 unleaded. then I ran a few logs all in 3rd gear, and I did one sitting still revving again. I also did a log in 6th gear on the hwy just cruising then getting on it, letting off, getting on it, letting off.

I've attached the logs below. input?

Have you tried swapping injectors around in the cylinders to see if there is a dead/clogged injector?

all 4 injectors are brand new. i found one that looked like it might be bad, so i replaced all 4 with bigger FIC units. 750cc.

thank you for taking the time to try to help, but please read through the thread before offering advice. everything i've tried so far has been covered and I need new ideas. thanks again though.

you also didn't try my suggestion. :P

no, I didn't swap injectors around because they are all brand new. this issue started on the original injectors, so when I found one showing signs that it was bad, I replaced all 4. there's no point to swap brand new injectors around when there are no signs pointing to any of them being bad.

the only sign that anything isn't right is the fact that my #1 cylinder is clean, but I have no idea why.

also, please comment on the logs. the race gas SHOULD have cleared the knocking up if it were real knock, but the knock is still there. also note that the knock voltage doesn't really move at all, even when the car registers knock.

did you edit the logs or are the gaps in data always 2,000rpm? It looks like depending on what the actual boost level is the timing is about right...for 22-24psi. If its higher than that something is definitely not right.

cant remember if I asked already but you did check to make sure the EGR was hooked up right?

aaron

Knock doesn't look that bad to me. Looks like it has a tendency to start knocking while the AFRMAP still is showing a pretty lean value. Perhaps the tune is just a bit lean in that area. Not sure that race gas can stop the knock if its really lean.

as for the gap in data, are you talking about at the beginning of the pull? I didn't do any editing of the logs.

the EGR itself, or the vacuum line on the EGR? the vac line was loose, but that was fixed long before this.

I see. I'll have my tuner take a look at that. two different tuners had the car, and with both tunes it did this.

also, which tune were you talking about? did this problem happen with both tunes, or just the one with the racegas?

I don't have access to the logs right now because I'm at work, so that's why i'm asking questions about your findings. thanks again for all the help.


oh, and does anybody have any ideas about why my #1 cylinder is clean? so far does this look like real knock? if so, what about the knock voltage not spiking?