KR maxing out on pull

[62chevy302]

I have had a guy helping me that seems very knowledgeable. This engine is a 5.3 with 11.1:1 compression and a BTR truck norris cam. Truck runs great but when under a pull KR will max out to 9.9 everytime. Tuner thought knock was not false, but I added 50/50 mix of 93 octane and 110 octane to see if anything changed. It did not. I hear a little lifter noise at 1500rpms and I am unsure if that is what it is picking up. I have attached a log and a copy of the tune. It was pulling some time at idle and he desensitized the knock sensors at low RPMS. Im not sure what to do at this point. Desensitize the knock sensors or tear it down and replace lifters or? I am hoping on of you experts can look at this and see something. TIA

[5FDP]

C'mon brah, the reason why has been right in front of you this whole time.

The log shows you have both knock sensor codes, that is 100% the reason why it's yanking all the timing. Any pending or current knock sensor code will make the computer pull whatever the max amount of timing is set in the tune file.

Fix the knock sensor codes and it will stop doing what it's doing.


I know the tune is a work in process but that tuner is pretty rusty in his craft. The cylinder volume is wrong for a 5.3, so all the fueling calculations are wrong. The VE looks untouched. The wide open throttle air fuel ratio is very rich, the timing tables need more work. Burst knock should be disabled. The injector data is suspect without knowing what you are running.

[Fast4.7]

C'mon brah, the reason why has been right in front of you this whole time.

The log shows you have both knock sensor codes, that is 100% the reason why it's yanking all the timing. Any pending or current knock sensor code will make the computer pull whatever the max amount of timing is set in the tune file.

Fix the knock sensor codes and it will stop doing what it's doing.


I know the tune is a work in process but that tuner is pretty rusty in his craft. The cylinder volume is wrong for a 5.3, so all the fueling calculations are wrong. The VE looks untouched. The wide open throttle air fuel ratio is very rich, the timing tables need more work. Burst knock should be disabled. The injector data is suspect without knowing what you are running.

While I agree 100% on the tuning needing work, I 1000% disagree with disabling burst knock especially on a high compression engine that may have a tendency to detonate on throttle tip-in if the transition fueling is not perfect.

[Alvin]

Yeah if it has any knock sensor code it will default to max retard when in PE.

[62chevy302]

I had adjusted the cylinder volume because the engine was bored .030 over. Should that stay at the stock setting?

The knock sensors and harness are all new gm parts. I have seen others have the codes to not report and the knock sensors still work as designed. I haven't heard anything besides some lifter noise and I dont think I have any mechanical issues in the engine.

The tuner had added wot fuel to attempt to bring the knock down. We have not messed with the timing alot because of the KR.


As for injectors, they are gen 4 5.3. They where on the nnbs intake off of a 08 envoy. Im not sure if he changed the injector data from gen 4 to gen 3.

I dont know what I need to do for that.

[blindsquirrel]

3.78 + .030 = 3.81
3.81 x 3.81 x .7854 x 3.622 = 41.2942

[blindsquirrel]

Your 43.0688ci would be a 3.891" bore? Which would be .111" overbore, not .030".

The way you deal with the injector thing is, you get the part number off the injectors (most likely 12580681) then find that number in the .xls file linked at the bottom of all my posts.

[62chevy302]

Ok, I made the changes with the injector table and cylinder volume. Should I have knock sensors to not report and see how it does?

[5FDP]

I've seen new parts still cause the codes for the knock sensors. For sure non AC Delco parts will do that.

Setting them to no error reported should be fine, they should still work as normal. You can test that too, do a log and smack the block or other various hard things with a soft rubber mallet to see if they pick up the vibration.

[62chevy302]

I will do that and report back with a log.

[62chevy302]

I updated the injector data and cylinder displacement. I updated the knock sensors to no error reported. I made a pull and the KR still maxed out. scratching my head.

[GBull]

I updated the injector data and cylinder displacement. I updated the knock sensors to no error reported. I made a pull and the KR still maxed out. scratching my head.

I recently chased a timing retard problem. Did you eliminate all your knock sensor codes? Make sure all your injector data is correct? Displacement? Did you torque your new knock sensors? Assuming you did all this, have you checked your grounds? Grounds were part of my problem and ya don't know they are good until you remove them, clean them...you get the picture.
With all that said, I too have a truck norris cam in a stroked 6.0l(now a 6.6l). My compression is accurately measured at 10.35/1. This is my tune with a completed VE table and a spark table that finally stopped retarding. Your VE table seems a little lean comparing to mine-not that they should be identical or even close but I don't see anywhere in your VE where you reached 100% volumetric efficiency.
Try giving my timing a try, it shows reduced timing in the peak torque area right where you are having trouble.

[GBull]

I updated the injector data and cylinder displacement. I updated the knock sensors to no error reported. I made a pull and the KR still maxed out. scratching my head.

Also log Burst Knock. I ended up zeroing mine out.
Consider the settings in power enrichment also. are you running ethanol free gas?

[62chevy302]

I am not running ethanol free. I am running 93. Right now I have a 50/50 mix of 93/110 to see if knock is fuel related.

[blindsquirrel]

Nuke P0325, too, since it only does it in PE and when it does it goes straight to the max allowed retard, never anything inbetween.

[62chevy302]

Removed P0325 and made a pull. Still have Knock Retard. I did notice something different this time. There are a few small blips of where it is not at max timing retard. I did log burst knock with no results. Thoughts?

[Russ K]

Try these changes. Your injector flow rate table is set for a non vacuum referenced regulator, you will need to correct it.

Russ Kemp

[62chevy302]

I am running a return-less system. The fuel pressure regulator is in the fuel filter next to the tank.

[62chevy302]

I would still use the injector settings for a returnless system?

[blindsquirrel]

I would still use the injector settings for a returnless system?

Yes, but your Offset vs Volts vs VAC has all columns the same, like it would be with a referenced regulator.