Help with too much KR...The car, a 01 C5Z LS7 H/C

[Rudolph]

Hello,

I am here a bit more than just desperate. The point is that, it is being almost 5 months since I had the chance to finish the assembly of my completly new LS7 motor (new block, new rotating assembly, TSP LS7 265cc heads, SLP headers, LS7 lifters, Vararam, 11.7 SCR, etc.), which was installed into my 01 C5Z. The car already has 700 miles in the odo, and as you would imagine I have been working with street tune up of the PCM, using HPT.

The PROBLEM, KR by 2,400 rpm till 4,800 rpm (sometimes even further). And let me tell you that I have more than clear the point that I have to adjust the setting of the KR sensors, which as you would imagine, I have...Nevertheless, the situation is present, and the level of frustrationg is getting high

I have played endlessly with calibration, parting from Knock sensor level in Tip in, RPM, as well as with Global Gain.

Would you mind to take a look into my HPT files, and suggest me a fix? Is going to be appreciated big time.

FYI, the car is using NGK TR6 (colder plugs), here in Mexico City we have 92 octane gasoline, Racetronix fuel pump as well as the harness upgrade. The fuel injectors are the LS7. The Knock sensors are new and were installed by modding the block (different bolt pattern), the puter is the one that came with the car, as I used a 24X reluctor ring, as well as 1X cam sprocket. BTW, the Knock sensor?s harness is Katech, and bought new.

Thanks in advance.

Rodolfo LPC5 Z06 with 427ciLS7 Lingen timing 03 noviembre 2016.hpt04 diciembre 2016 19 02 horas.hpl

[5FDP]

I'd make sure your airflow tables are dialed in before trying a whole bunch of other things.

Currently that VE table is all sorts of jacked up, not even sure how it could have ended up that way but it's for sure not helping you here at all. I'd spend some time speed density tuning the VE, then work on the MAF to know the airflow tables are good.

[Rudolph]

I'd make sure your airflow tables are dialed in before trying a whole bunch of other things.

Currently that VE table is all sorts of jacked up, not even sure how it could have ended up that way but it's for sure not helping you here at all. I'd spend some time speed density tuning the VE, then work on the MAF to know the airflow tables are good.

Thank you so much for the replay.

I would like to share with you, that I just saw in my log that the car is going way lean at WOT... I am checking in my tune if it is something I completly overlook, or a huge mistake(most likely). I have even consider that a wiring problem is there, or the pump even tought it is new, might be not working properly. I look into the tune first (crossing finger for not finding out it is mechanical).

Rodolfo LP

[schpenxel]

Yeah, VE table def needs work. It should be fairly smooth.. yours has huge spikes/dips all over the place

[Rudolph]

Yeah, VE table def needs work. It should be fairly smooth.. yours has huge spikes/dips all over the place

Thanks a lot for the comment... Now, my point is, does the "un-eveness" in the VE table could case the PE mode not to trigger???? I will be looking for a mechanical / electrical situation causing the lack of fuel at WOT, but I am more incline to think there is a problem with the tune...

Thanks a lot.

Rodolfo LP

[schpenxel]

Nah PE should trigger regardless. I'll check out the other settings for that shortly.

[schpenxel]

It is going into PE..

Have you tried adding something like torco (octane booster) along with lowering the time drastically to see if the knock is not real?

Add O2 sensor B2S1 and also add both injector PW bank 1 and bank 2 to the list of channels you are logging

[Rudolph]

It is going into PE..

Have you tried adding something like torco (octane booster) along with lowering the time drastically to see if the knock is not real?

Add O2 sensor B2S1 and also add both injector PW bank 1 and bank 2 to the list of channels you are logging

Thank you a lot for the time and attention shared by looking into my files and comment.

About the octane booster, is difficult to get TORCO down here (Mexico City), as the only thing I can get is the NOS octane booster sold at Autozone... Would it help? It is only MTBE, right? I would give it a try.

As for the timing, I will try to reduce it drastically, as I have already try reducing 2 -3 degrees at most (sometimes helps, some other no). Also, sometimes the KR comes present in one line the engine load chart, such as 0.40 gr/cyl, but other times it is present as the attached file (all over the place).

I will load the variables you are asking me for, during the week; come back, soon, and seek for your help.

Thanks again.

Rodolfo Lara

[Rudolph]

Hello again.

Guys, after taking care of some things (mechanical) of the car, such as new Racetronix fuel pump (had a Walbro conventional that was indeed failing), checked all the grounds from the upgraded fuel harness. I took care as well of the tune up, which in my opinion is now "more" refined... But after all the work, I am still getting lots of horrible KR, but it based on the Maximum Knock Retard vs. RPM (PE) table, and not other table.19 de marzo de 2017 17-34 horas still MORE of PE KR with PCV fix (once well).hplC5 Z06 with 427ciLS7 Marzo 04 de 2017.hpt

I have searched with a fuel pressure tester that there are valleys while under WOT, and it is fine. WHYYYY am I getting this much PE KR... Some insight will be more than thanked.

Rodolfo Lara P

[Lakegoat]

If you are having a lot of knock, it looks like you should have your Low Octane timing table lower than the High Octane table. You have no safety net when it knocks.
It looks like in this log, the first two wot runs, you have no knock. It is after you let off the gas. Is that correct? Do you have anything like an exhaust pipe rattling against the frame?

[Rudolph]

I will set the low octane table lower as you suggested... Good point.
Now, as you saw I have a problem with the car knocking suddenly, and the funny thing is that it does it even when not in throttle as you mentioned.
It is important to mention that I have a PCM code P0332 in Current status, which refers to the Knock sensor, and I replaced it, and still the DTC persist... I have read that this problem should not set KR, am I correct?

[Lakegoat]

Is the knock sensor wiring ok?

[Rudolph]

Is the knock sensor wiring ok?

The harness looks fine. It is a Katech adapter for the side knock sensors, and installed new with the motor.

[jc052685]

knock sensor data is not the same between the two types of sensors.

[Rudolph]

knock sensor data is not the same between the two types of sensors.

I know that there is a difference between the Resonant type to the Flat Response on regular 4th gen cars, but I have taken measures accordingly as to modifiy the sensibility of them... But, the point is that the engine's car sometimes knocks under light loads and some others under high stress or revs, does not... This is the interrogative I bring into this forum for some insight.

Thanks a lot.

Rodolfo Lara