Major tune issues

[GMCtrk]

Ok, here's the situation. I have a stock LQ9 in a truck, only mod is ported heads and milled...10.6:1 compression. I bought EFI live several months ago and found out on logging that I was having massive KR at wot and my LTFTs were like 10%. I sent this to my tuner and he said I had an air leak somewhere. Fast forward to today I changed out my intake manifold gaskets and throttle body gasket. Logged after that, same thing. 7-8 degrees of KR at wot. We then added 2.5% to the VE table, and 5% to the MAF table below 5000hz and 15% to the table above 5000hz. My o2 readings are looking much more suitable (.900-.930mV at wot versus .750-.800mV before the changes) but I'm still getting the KR and now at WOT around 4500-5000 rpms the engine starts feeling like the power delivery is "wavey" and or slightly surging. I'm still wondering if I have an air leak or what was going on. I dont know what could be leaking. Other than the changes I made, I'm running a stock GM 2002 LQ4 tune. The first log I am attaching is from May, the next one is right after the gasket swap on the stock tune, and the final one is with the fueling changes. If I put the truck in 2nd gear and punch it from like 40, it seemed with the final changes that it pulled good with no KR, but it only does 14 degrees of timing? :bad: Whenever it tries to bump up to the high spark table, it instantly bursts 7-8 degrees of KR.

[mr.prick]

Have you reduced the Knock settings at all?
You should not rely on NBO2 voltage for AFR and
adding X.XX% to MAF and/or VE blindly is generally looked down upon
as a tuning technique.
LTFTs don't look too high in the final log, this may indicate you don't have a leak.

[GMCtrk]

Have you reduced the Knock settings at all?
You should not rely on NBO2 voltage for AFR and
adding X.XX% to MAF and/or VE blindly is generally looked down upon
as a tuning technique.
LTFTs don't look too high in the final log, this may indicate you don't have a leak.

I will not mess with the knock settings because I dont have enough experience and want that safeguard if indeed this is all true knock (which I believe it is). I dont have a wideband, so going off the narrowbands is all I have. I really just want this thing to run at WOT without any knock. I've been running on a stock LQ4 tune forever and it's just a dog. I've been waiting to change out the gaskets almost all summer and finally got it today but that didn't change any of the problems I was having before. What are the next steps I should take? BTW, my tuner is Justin Gadberry, I'd love to have him tune it live but he's not going to be in my state any time soon I believe. This issue Ive been having is really holding me off from adding any other mods because I need to get it running right first before compounding the problem. I really did not imagine that adding ported heads and increasing compression was going to screw things up so bad.

[jetblast]

your strategy for combating kr and the lack of fuel is fine, for now. i'm assuming that you are using 93oct fuel, anything less is not adequate for the mods you posted. o2 values of less than .900mv is not good enough. since you do not have a w/b, it's ok if you just tune to .915mv using the nb o2 sensors, .920mv to or higher is probably too rich. wot tuning takes place on the last 1/3 of the entire load colums of the ve table, so 2.5% encrease is a good target. the maf table is way too high, instead, try 2% encrease from 8khz to the top. take the stock high oct. timing table and subtract 2* deg from .44gm/cyl to .120 or what ever the max is on your table and 3200 to max rpm colums. the last log that you posted seems that too much timing was removed. make a wot run with these settings, and report back. the other area that needs tuning with your mods is the low to midium load areas, which is indicative of the large positive ltfts, add 4% to the ve table in those areas, but do not touch the idle area, which is the 400 to 800rpm colums. i would not advise anyone who is in the beginning stages of learning to tune, to decrease the kr sensitivity tables. this forum will guide you in using the more sophisticated and accurate method of tuning, for now it's important that you get rid of kr. in the future, it's a good idea for you to get a w/b. the last subject i would like to mention is that the weight of a vehicle affects timing strategy, a heavier vehicle will require a little less timing than a lighter one,[ truck vs corvette]. if you could post your current tune i would be glad to review it. good luck either way.

[Doc]

What other mods do you have to the truck besides the heads? Exhaust? How many miles are on the truck? Cats/No Cats? Plugs?

[GMCtrk]

your strategy for combating kr and the lack of fuel is fine, for now. i'm assuming that you are using 93oct fuel, anything less is not adequate for the mods you posted. o2 values of less than .900mv is not good enough. since you do not have a w/b, it's ok if you just tune to .915mv using the nb o2 sensors, .920mv to or higher is probably too rich. wot tuning takes place on the last 1/3 of the entire load colums of the ve table, so 2.5% encrease is a good target. the maf table is way too high, instead, try 2% encrease from 8khz to the top. take the stock high oct. timing table and subtract 2* deg from .44gm/cyl to .120 or what ever the max is on your table and 3200 to max rpm colums. the last log that you posted seems that too much timing was removed. make a wot run with these settings, and report back. the other area that needs tuning with your mods is the low to midium load areas, which is indicative of the large positive ltfts, add 4% to the ve table in those areas, but do not touch the idle area, which is the 400 to 800rpm colums. i would not advise anyone who is in the beginning stages of learning to tune, to decrease the kr sensitivity tables. this forum will guide you in using the more sophisticated and accurate method of tuning, for now it's important that you get rid of kr. in the future, it's a good idea for you to get a w/b. the last subject i would like to mention is that the weight of a vehicle affects timing strategy, a heavier vehicle will require a little less timing than a lighter one,[ truck vs corvette]. if you could post your current tune i would be glad to review it. good luck either way.

I greatly appreciate your input and help. I am attaching the current tune (blackGMCtune) and the original base tune which was a stock GM 2002 LQ4 tune. Indeed I am using 93 octane.

[GMCtrk]

What other mods do you have to the truck besides the heads? Exhaust? How many miles are on the truck? Cats/No Cats? Plugs?

Just 4.10s and a trutrac limited slip out back. Everything else is stock down to the air filter. I actually just finally ordered a CAI.

[GMCtrk]

your strategy for combating kr and the lack of fuel is fine, for now. i'm assuming that you are using 93oct fuel, anything less is not adequate for the mods you posted. o2 values of less than .900mv is not good enough. since you do not have a w/b, it's ok if you just tune to .915mv using the nb o2 sensors, .920mv to or higher is probably too rich. wot tuning takes place on the last 1/3 of the entire load colums of the ve table, so 2.5% encrease is a good target. the maf table is way too high, instead, try 2% encrease from 8khz to the top. take the stock high oct. timing table and subtract 2* deg from .44gm/cyl to .120 or what ever the max is on your table and 3200 to max rpm colums. the last log that you posted seems that too much timing was removed. make a wot run with these settings, and report back. the other area that needs tuning with your mods is the low to midium load areas, which is indicative of the large positive ltfts, add 4% to the ve table in those areas, but do not touch the idle area, which is the 400 to 800rpm colums. i would not advise anyone who is in the beginning stages of learning to tune, to decrease the kr sensitivity tables. this forum will guide you in using the more sophisticated and accurate method of tuning, for now it's important that you get rid of kr. in the future, it's a good idea for you to get a w/b. the last subject i would like to mention is that the weight of a vehicle affects timing strategy, a heavier vehicle will require a little less timing than a lighter one,[ truck vs corvette]. if you could post your current tune i would be glad to review it. good luck either way.

Ok, here is the tune with the suggested changes you have recommended

[GMCtrk]

Just took a log, looks like those changes made me go lean again and still knock.

[jetblast]

that's ok, revert back and do 4% to the ve from 13.8 to 15.2 and select the linear blend feature, select blend colums only and encrease max blending. revert back add 4% from 8khz to 12khz. the mv o2 sensor values are still lean with the previous 2% and 2%addition of fuel. you want to contnue this balanced strategy until you get the desired .915mv, don't do anything more to the timing, it looks fine under the last wot run you made. once you get the .915mv you should not have anymore kr. and if in fact you don't have anymore kr then add timing 1* at time until you see kr, then back off 2*. this is just a ballpark figure, and in colder air you may need to back off a tad more. the w/b will tell you more accurately were your target afr should be. 12.8afr is my personal choice. make another run with the added 8% total fuel addition and post the run.

[GMCtrk]

No changes I have made helped. I changed all of my spark plugs with new tr55's. my old plugs looked GREAT. I also bought a set of new coils to try out.

One thing someone mentioned is a crank relearn. I have never done one, my truck has had at least 5 pcms in it, and 1 engine swap. But I've never thrown a code or anything related to a crank relearn. Could that be somehow causing this? I'm baffled.

[Big Mike]

No changes I have made helped. I changed all of my spark plugs with new tr55's. my old plugs looked GREAT. I also bought a set of new coils to try out.

One thing someone mentioned is a crank relearn. I have never done one, my truck has had at least 5 pcms in it, and 1 engine swap. But I've never thrown a code or anything related to a crank relearn. Could that be somehow causing this? I'm baffled.Then in that situation I'd without a doubt be doing one asap.

[Chuck L.]

Any fuel pressure check[s] been made?

[GMCtrk]

No, but I have recently put in a brand new OEM fuel pump

[vxchev8]

Lower your PE mode from 90% throttle and disable cat protection

[Chuck L.]

No, but I have recently put in a brand new OEM fuel pump

check it to see if it's maintaining PSI @WOT....:hihi:

[jetblast]

No changes I have made helped. I changed all of my spark plugs with new tr55's. my old plugs looked GREAT. I also bought a set of new coils to try out.

One thing someone mentioned is a crank relearn. I have never done one, my truck has had at least 5 pcms in it, and 1 engine swap. But I've never thrown a code or anything related to a crank relearn. Could that be somehow causing this? I'm baffled.

did you add more fuel as i suggested? you were not very far off from the first tweak i suggested to you. trust me kr will go away once you reach that magic .915mv or so. your tuner took out way too much timing. if you noticed the kr almost went away when you added 2.5 to the ve and 15 to the maf but it was too much and too little timing giving you a very inefficient burn, hence you had some minor kr. in n/a configuration, it will be very hard to hurt the motor as long as you maintain a conservative timing curve of not more than 22 on your wot runs. if you are worried about kr ruining the motor than why don't you just do 6 and 6 for the ve and maf tables respectively and work your way down.

[joecar]

Bump for OP.

What is the stock compression ratio.

Now with milled/ported heads your compression ratio is 10.6...?

Do you have pics of the ported heads...?


From log posted below, KR shows sawtooth pattern:

15354

[GMCtrk]

the LQ4 is 9.4:1, the LQ9 is 10.1:1. Both of those engines use the same VE table and MAF table from the factory. I dont have any pictures of the heads. They are just standard CNC'd heads. I will purchase the LC-1 now to monitor AFR and then if it knocks still with good AFR I will add race gas and see what happens. I did the calculation and with the stock cam's lift of .470" I am getting 30 cfm more flow with the ported than stock heads. I also added a catch can.

[Chuck L.]

Referring to post # 16.. Did you check the FP @ WOT??

[GMCtrk]

Just put a mechanical gauge on it today.

It reads 55 psi with the key on, engine off. 49-50 psi at warm idle, and 58 psi at WOT. It's a return style fuel system.

[GMCtrk]

Im attaching a copy of logs as well as the tune. One thing I've noticed through all of this is that my KR always comes on between 3800-4100 rpms.

[Mr. P.]

On your log, does the KR look like a sawtooth pattern (a bunch of repeated spikes) or like a plateau, or a single 'attack' of KR that smoothly decreases to zero?

Mr. P.

[GMCtrk]

mostly sawtooth

[Chuck L.]

Truck intake?
Any leak at the intake where the MAP sensor plugs in?
U using the stock crankcase venting?
Any leak at the plug, upper dr side rear of the intake?

[GMCtrk]

Nope, no leaks. I put on a whole brand new intake and everything (fuel rails, injectors,etc) like 2 weeks ago. I use a catchcan with the normal routing from the driver's valve cover to the intake.

[Chuck L.]

Nope, no leaks. I put on a whole brand new intake and everything (fuel rails, injectors,etc) like 2 weeks ago. I use a catchcan with the normal routing from the driver's valve cover to the intake.

you have the can plumbed? There's a "right way" to do that.:hihi:
Here's some "food for thot" type reading. Oil pulled into the engine will make it knock.
http://www.ls1tech.com/forums/generation-iii-external-engine/1054089-my-catch-can-routing-ok.html

[GMCtrk]

the truck pcv setup is different than the ls1's. I've got the catchcan between the dirty side (driver's rear valve cover) and the intake manifold. It should be catching the oil. I've only had it on for a couple days now. I'll check it in a month of so and see if there's oil in it.