Looking for some guidance on a tune

[fijiblue1]

looks like there's fewer knocks now 18 on #4. similar to revision 01. Seems to be running leaner then before and i see there's spikes in the AF around 4300 and 6000, what cause that?

[EFICU]

Yeah it's a little interesting because we are now 6-8* lower than normal ignition I've found on these and still getting the knock, though the count is lower which makes me more curious. You might drive it again like before, where the count went down and then came back. What octane fuel are you running?

Those lean areas are something I've been watching, though it's not considered lean really in an unsafe AFR, but I have been watching how the AFR never seems to smooth out for the entire pull. That and that and the knock makes me curious if there is something going on in cylinder 4 that we can't see in the datalog. It might be something you want to look at again and either replace the injector, or see if something is still strange in that cylinder physically.

[fijiblue1]

Should I be worry driving around with it being 6-8* lower then normal? I'm in Ca so we only have 91. What do you mean drive it again like before? Do more runs or try the rev01?

[EFICU]

No there is nothing to worry about with lower ignition, especially for testing. We don't want to put negative ignition in of course, but lower ignition from what I normally run is no problem. We are basically just gathering data and testing scenarios to see what we can determine. I always try to find the issue instead of bandaiding things. I'm not a fan of bandaiding things, we want to try to find the issue so you can enjoy the car with no worries.

Gotcha, yeah 91 sucks I know, especially when it's over $5 a gallon right now, sigh. I just mean to drive it again with the same calibration, and let's see what knock count we get. Like before, our knock count was a lot lower that before, then it jumped up again. So lets see how it looks with data from two datalogs and see what we get. If the second datalog only has 18 knock, then we might be on the right track. If it jumps up again, then we can discuss the next move then. Drive it like you have been in the most recent datalog, I don't want you doing a ton of pulls if the knock is real and excessive.

[fijiblue1]

Did a few run this morning and just now. Seems like the knock is coming back up.... ugg. Could it be ghost knocks? I noticed it's a bit sluggish between 5600-6k. I assume there's a correlation with the AF ratio spiking up in the 13s.

[EFICU]

Since you don’t have the typical mods to cause false knock, it would be unlikely to be false. And also that you are concerned about that cylinder anyways I think there might be something with that cylinder. The sluggish feel is from the reduced timing I put in it to test, right now my focus is on the knock, not so much performance.

The afr changes don’t seem to be very consistent. You might want to set aside some time and look at cylinder four again. What exactly happened again with that cylinder, the injector might have been damaged or stuck?

[fijiblue1]

the only thing i did was when i pulled the injectors out, #4 was pull out at an angle instead of straight out.

[EFICU]

I see. Seems like such an innocent thing so who knows honestly. Normally on something like this I have guys swap parts from one cylinder to another to see if the issue follows. With a potentially slightly damaged injector though I’ve never done that. Might be worth a shot though, or swapping coils or plugs to see if the issue follows. That might be something to test.

[fijiblue1]

yeah, going to have to get that done, swap out the with another cylinder and see how that goes, then do another datalog run.

[EFICU]

Sounds good man. Sorry, I don't know what else to do but start there. Just keep me in the loop, and in the mean time, stray away from too many WOT pulls while you await swapping parts. Then we will see how it looks once you swap parts.

[fijiblue1]

When we are talking about cylinder #4, are we talking about the the 4th cylinder on the right facing the engine next to the air box or the firing order which is the 3rd cylinder? I don't know which cylinder FP is referring to for the knock

[MM082001]

When we are talking about cylinder #4, are we talking about the the 4th cylinder on the right facing the engine next to the air box or the firing order which is the 3rd cylinder? I don't know which cylinder FP is referring to for the knock

Another thing to check is your spark plugs while you are there. I had one with a bent electrode on my last change.

[EFICU]

When we are talking about cylinder #4, are we talking about the the 4th cylinder on the right facing the engine next to the air box or the firing order which is the 3rd cylinder? I don't know which cylinder FP is referring to for the knock

Cylinder 4 should be the closest to the driver side of the car, cylinder three would be the one to the left of the #4 cylinder. So yes, the closest one to the airbox is cylinder #4.

[fijiblue1]

Looks like I'm still getting knock on #4, switch out the injectors, did a run, same knock, also switch out spark plug and same. I do noticed there's a 1-2% Strim correction at some point. Not sure if that matters. Anything else you think I can do?

[EFICU]

Yeah that's strange then. Might be something with that cylinder, though that wouldn't make much sense. Can you post a datalog you made after swapping everything, then I can look it over and see what it looks like?