ECMlink Cant figure out where this knock is coming from!

[crash89]

Hey fellas, this is my first time posting a log so I hope it works!

Little background, Mr Peepers is the guy who usually does the tuning on the car but due to schedules I want to try and figure this out myself so Im not bugging him all the time. Last season the car was still on V3 and my 20g and was tuned to ~20psi and was great. After I got my engine installed and my Holset setup on the car I kept getting a bit of knock and we couldnt figure out why. Cruise is dialed in great but basically as soon as I get into boost I see almost 3* of knock. Ive seen the videos on ECMlink.com and have read some wikis so I kind of have a little knowledge with link, but not much. Its just so much easier for me to drive and Matt to hold the laptop.

Ive tried a couple different ways to see if this knock would keep coming up. First I eased into it in 3rd gear and started knocking at ~3800rpm.

Second pull was a WOT 3rd gear pull and still saw knock at 3900rpm..

Third was in second gear slowly increasing speed while keeping boost as close to 0 as possible. Still knocked at 4800rpm.

I was wondering if you guys would be able to take a look at these logs and give me some advise or your thoughts on them!!

Stock shortblock
BC272s
1000cc injectors and 255 pump
hx35 12cm housing, twin scroll
91 oct pump gas and speed density

 

[dsmcurse]

right click on ## log. go to combined fuel trims and click. it should put u at speed density tables with suggested values that are in bold black. click save all to ecu. now take the mouse curser and go to the top where it says ecu. click there. now hit reset fuel trims. this should help

 

[crash89]

I should do this after logging a live pull correct? Ill have to try this tomorrow.

 

[dsmcurse]

i ddo it every other time i drive the car. it keeps gettin smoother and smoother

 

[crash89]

Wait, isnt this just for dialing in cruise? Cruise is just fine, its boosting and anything more than 40% throttle Im getting knock.

 

[andrewshowers]

I may be wrong here, but it looks like you need to add a taste of fuel between 3800 and 4000 rpm. Your wb says 11.7:1. Just my 2 cents.

 

[crash89]

I may be wrong here, but it looks like you need to add a taste of fuel between 3800 and 4000 rpm. Your wb says 11.7:1. Just my 2 cents.

Your right, but Im still building boost at that point. When I hit full boost the wideband sees 10.5 or lower. Weve tried taking a bunch of fuel out too, maybe still need to take a little out.

 

[crash89]

Ok, so I saved a revised log I got from a guy on the Link forums and preceded to play with fuel and timing to try and get rid of this knock. Sometimes it seemed like I was getting somewhere then the next pull was totally opposite. Tried taking fuel, giving fuel, taking and giving timing and still am getting this knock at ~4000rpm.. I set my MaxOct table to reflect what I feel it should look like. Then I kept trying to play around with the SD table via (ECU config live button on log) .. Sometimes it seemed like it would get better so Id try and take out a degree of timing, then next it would be worse. So Id give a couple..

I did notice that my timing table and what the log was seeing for timing were totally different. No idea why!??!? Could this be the problem? Maybe phantom knock?

I finally got frustrated and just left it at the last change I made.. Im pretty sure I took a decent bit of fuel out, as my AEMwb in my log is going a decent amount lean.. I should probably add some fuel back correct??

Also, since I started messing with this Ive noticed that I am WAY lean between shifts.. For example shift from 2nd to 3rd at ~2700rpm, while starting in 3rd my WB reads --- and I feel absolutely no power at all to increase speed.. I took a log of this as well.

Thanks for any advice in advance!

 

[crash89]

Little bump here.. If youd like to read the Link forums thread between J Diz and myself >> ECMTuning User Support Forums But heres what I did today after he told me that I needed to get my AFRest and wideband to match.. Copy and pasted from that thread..

Alright guys, I made some adjustments via the formula that J Diz suggested. I for the most part understand what was done here however, at some points the formula suggested my new VE value be upwards of 103+.. I didnt put those values in, just left them how they were. I got my wideband to be as close as I could get to the AFRest. Some points Id make an adjustment and it would go from above to below and vice versa so I just left them as close as I could.

Now, during my little "tuning" session I noticed that during every pull my knock count was never the same. Ranged from 3 counts to 9+, all of which almost right at 4k. I also noticed that I my AFRest was going a little right when knock was coming in. I tried to adjust the fuel sliders slightly to maybe get that to stop but didnt do much.

So, heres a few logs from today. First one is what I started with, no adjustments. Second log is right after my first adjustments. 3rd log is my stupid high knock and last one is what I stopped with today. Questions, comments, advice!!

 

[Simadowna119]

I've never seen so much timing pulled in my life. I'm pretty new to tuning. But the more timing I pull the less power I feel. I have had pretty much the same issues. here is exactly what i did to completely get rid of knock and keep a stock timing table and close to stock base timing. Not just one of these but all of these things done together cured my knock. I have owned 4 DSMs and have learned that through a process off trying to figure out knock with all of them and not completely figuring it out untill my current car.

Each one of these is a must!

1. Installed 3g revised lifters

2. Put CAS at *3 degrees. BTDC is should be set at 5*

3. Install wideband and get A/Fs right

4. Get fuel trims dailed in.

5. Go to your timing graph and pull just 1 degree on the sliders from wherever the knock starts in RPMs to wherever you let off the throttle. Keep the "timingmaxoct" stock.

6. Go to the fuel graph and push the sliders up a little and add some fuel where you start to get knock. I added 0.5% starting at 45k RPMs going up to 1.5% at 55k RPMs (where i get the highest counts of knock)

7. Install BR9ES plugs. These plugs will foul quicker than usual. But it's either this or getting beat by Ls1 or honda boy cause your getting massive amounts of knock and have to let out.

8. Don't run 91 octane! Don't run 93 or 95 octane! Run nothing less than 100 octane. I run 102 unleaded. cost me 7.25 per gallon. If you don have access in your town you can order online for a lot cheaper than 7.25 per gallon. You should'nt eat mcdonalds every day, and neither should your car. you have to pay to play!


Like i said not just one of these but all combined got rid of my knock. i have tried all this stuff to previous DSMs and it helped a little but i did'nt COMPLETELY get rid of knock until I did ALL this to my current car.

Somethings you may have to vary a little for you car/set up like how much fuel you add with the sliders or maybe you only have to put the CAS at 4*btdc to get the same results. But i believe this is a good and not to costly start to anyone with knock issues.

My friend was getting massive knock on his GST and we got rid of it entirely with the same process.

the setup i described up top is me doing JUST wait i can and nothing more to get rid of MY knock. Example is if i use bpr or br8es plugs i'll see a count or two of knock at 55k rpm. if i run 95oct ill get a count or two of knock. my friend runs bpr8es plugs. but like i said ever car is a little different and you may have to vary away from what i did exactly to match your cars needs. This is just a good place to start.

I'm on 16lbs of boost. my buddies gst is on 18lbs. before this setup the only way i could get rid of knock without pulling mass amounts of time (like you have) making the car way slower is to turn the boost down to 8lbs. yeah.... #### that.. now the car feels great!


Not saying this will, But boy I sure hope this helps you or someone after all that typing.



By the way, parts on my car are,
2g maf
3" turboback exhaust
tubular o2 housing w/open waste gate dump
3g lifters
hard 2.5 IC piping
2.5 to 3' injen intake pipe
16g turbo
rebuilt OEM ported polished head.

 

[boost97gst]

^^^ yup, nothing like high octane to get rid of knock!! . I do agree about the colder plugs. Im getting problems out of my br7s, switching to br8s tomorrow. 91 oct is shit. It may be ok on a hx40 or 52 but i think you need to try adding a couple gallons of e85 to the tank on fill ups. I know its just guesstimate type shit but it works and doesnt hurt anything. What you will mainly notice is your fuel trims will be off during cruise, it will have to dump more fuel in to hit stoich. But i would really target 11.0 and under heavy load with 91, i would be looking for an even richer afr. Dont ever lean out to get rid of knock, unless your like 10:1 or something crazy. Then you COULD be getting rich knock.

btw, im commenting without looking at your logs, just what you wrote. This cold weather is what we all wait for too. Sucks youre knocking. Im pushing 53lbs on straight 93 tonight no knock cel(didnt log but it had to be under 2*) Stock evo 8 mod 1 timing. On hotter days ill add roughly 20% e85 in the tank and that really kicks ass. I DO have to slide my mafcomp up a bit in the higher hz to compensate but its pretty easy to quickly bump em up 5%.

Just checked 3rd log in latest post: You need more fuel. It really really looks like your vac line to the afpr or fuel filter may be having problems. I can tell youre asking for more fuel but the afrs go all the way past 12 under heavy load. No bueno

 

[crash89]

We dont have 100oct fuel around here and no way in hell Im paying 7+ dollars a gallon for a DD car. We do have E85 but I wanted to see where I could get on pump gas. Theres been a bunch of people who've had pretty good results. Im still on a 7 bolt so no CAS adjustment here.. And I do have BR8 plugs.

BOOST07: I dont understand why you say pump gas would be ok for an hx40 or larger but not an hx35?? A buddy of mine in town is on the EXACT same set up as I am, tuned on e85 and dynoed at 511whp.. Just threw in 93oct on the way back from MOD just because. Dialed it in on the drive home and is now back up to 27 psi with no problems..

Regardless, I'm really thinking about flashing one of my logs from earlier this summer and starting over from wastegate pressure. So Im not chasing my tail like I feel like Im doing. And if I still knock down there I know something is wrong. The car never had this issue on WG pressure so something could be loose and creating a phantom knock scenario.

 

[boost97gst]

I dont know alot about holsets, i was just stating the fact that larger turbos tend to knock a bit less on pump cause they throw out colder air(relatively speaking), than smaller turbos. I have a 5858 which should flow around 60lbs peak, and i have no idea how i would max it out on 93. Im just not that good of a tuner . Nonetheless, on the log i looked at, you were lean.

 

[crash89]

Hey there guys.. Great news. I finally kinda figured things out and believe Im getting a decent grasp on this stuff!! A while ago right after I got link I found an article about how to tune but forgot to bookmark it so I forgot about it. Well I stumbled across it the other day and re-read it. Decided to just start fresh with my WOT tune. So, I flashed one of my first logs on the Hx35 on low boost and cranked down the boost controller. Good news started there. NO KNOCK!!! So I knew it had to be something in the tune itself that was messing things up. So, with going back and forth between reading and tuning I got this thing back up to 21psi with no knock! For the most part. Still a little bit of tweeking left to do, little more fuel and less timing in some areas but I think Im well on my way!! Heres a couple logs!! All of this was done in an hour or so!

Oh heres a link to the article I read by Dr Turbo! How to Tune a 1G V3 SD ECM LINK with no MAF V1-3 I know it says for a 1g but its V3 so its the same damn thing!

 

[TSITurbo95]

Your AFR's are all over the place. But other than that, it's alot better than before. After you adjust your cells, be sure to smooth them.

 

[crash89]

I know things arent quite perfect yet. This was my first time actually successfully "tuning" the car. Im pretty happy with the way things went. Hopefully will do some more tinkering with it today or tomorrow then going to the track on thursday. Hope to see some pretty decent times.