Why am I getting Knock Retard?

[leftyss]

I have attached a log with my tune file to see if anyone can tell if I have missed something. Not sure why I am getting knock retard? I have tweaked the knock sensor sensitivity but don't know if I have desensitized enough or not? Or if my problem is elsewhere. Any help is appreciated.


BTW not spraying in log.


Thanks.

[spike]

is it going into PE mode?

[murphinator]

the way your kr spikes look in chart display is weird - so block like and uniform , someone that has seen it look like that before will probably know just what it is caused by - false knock maybe ?

[leftyss]

why beta?

Sorry, I didn't even think about it being in beta. I will pull the tune in 2.22 and get a log this afternoon. I appreciate you trying to take a look though.

[madvette08]

I am having a look at your tune file now. Have you tried taking out 2 degrees of timing out to see if it goes away.

Ian

[leftyss]

I am having a look at your tune file now. Have you tried taking out 2 degrees of timing out to see if it goes away.

Ian

Well it was doing the same thing when I had it at 28 deg. Now it is at 24 deg and still pulling 3-4 deg. The timing part of tuning has always been something I have never gotten comfortable with so I just left the car at stock. A car with my mods, off the N2O, shouldn't be knocking with 91 octane, could it? I don't have any exhaust hitting either. The only thing that might be hitting is the header on the plasic cover for the heater core, only under heavy throttle though cause it is not hitting idling. Could this be causing false knock? Probably a stretch just thought I would ask.

[leftyss]

why beta?

Ok tune and scan in 2.22..

Any ideas?

Thanks.

[blownbluez06]

If you run the histogram and reduce the timing enough in the areas where the KR is showing up and get no results, it tells me your problem is not true knock. It doesn't have to be exhaust. I have seen cracked flywheels and loose converter bolts cause knock.

[leftyss]

If you run the histogram and reduce the timing enough in the areas where the KR is showing up and get no results, it tells me your problem is not true knock. It doesn't have to be exhaust. I have seen cracked flywheels and loose converter bolts cause knock.

Yeah, I could see either one of those causing knock. I hope that is not my case cause it was doing this before the converter install and I hope the dealer that installed the converter and rebuilt the tranny would've noticed a cracked flywheel (hopefully). Could getting a low voltage knock sensor code cause this?

[Frost]

Low voltage usually means the wiring to the sensor is bad/pinched, but I have seen this for a failed sensor as well.


Wait... this isn't real or false knock, it's what the PCM does when you have a bad sensor. You get -4deg ALWAYS when in PE if a sensor or it's related wiring are bad. It's obvious in the log file.

[leftyss]

Low voltage usually means the wiring to the sensor is bad/pinched, but I have seen this for a failed sensor as well.


Wait... this isn't real or false knock, it's what the PCM does when you have a bad sensor. You get -4deg ALWAYS when in PE if a sensor or it's related wiring are bad. It's obvious in the log file.

That is what i thought. Cause for awhile I had the PE Retard table, forget the exact name, zeroed out and never had any knock show up. When i put on the LS6 intake I also changed out the sensor that was throwing the code and after it was still there. There was however some oil down in the bowl of the knock sensor but didn't notice any on the sensor itself. Cleaned the bowl as best I could and put back together. Probably should've taken the valley cover off and resealed, but was in a time crunch when I did the swap. Would oil sitting in the bowl cause some kind of false knock? Not that it was in this case just thinking. Have heard guys changing out both sensor and still throwing this code, does anyone know why?

Is the PE knock retard table the only one that controls retard in PE? If not could I just leave this zeroed and let other parameters take timing out if needed? I guess I should probable pull the intake and reseal it up if I am still getting oil in there, huh..?

Thanks for the feedback Frost.

[Frost]

I'd pull it, replace both sensors and the pigtails. Unless you smash the new pigtails when you tighten it down, this generally gets rid of all of the issues.

Yes, you can 0-out the KR in PE and it will stop pulling until you fix you sensors.

[leftyss]

Thanks for help Frost.

How much HP do you think I could be losing with the 4 deg. timing pull? I know all cars are different, just a rough estimate on what you have seen with your experience.

Also typically what A/F ratio do you try to hit through the RPM ranges for best power when you tune? Once again each car likes different things I am just looking for a ballpark. The reason I ask is my car only went 108 mph in the 1/4 off the bottle and I am just wondering if my car just doesn't make good power with my mods or if my tune is limiting it or if that is what is should be running with the mods I have. Thanks again.

[murphinator]

Wait... this isn't real or false knock, it's what the PCM does when you have a bad sensor. You get -4deg ALWAYS when in PE if a sensor or it's related wiring are bad. It's obvious in the log file.

I knew those spikes looked too consistently flat on the tops - all makes sense now , learned something new

now just to remember that condition

[ssdungeon]

Yes, you can 0-out the KR in PE and it will stop pulling until you fix you sensors.

I zero'd the maximum knock retard vs. RPM and vs. MAP my goal is to just eliminate the knock sensors as the reason for pulling timing. I want to know ifthere is any other table I need to zero out to eliminate the knock sensors from pulling timing.

Thanks,

[bwkmaro]

ok i have a camaro with the same problem i just put the motor in im getting solid blocks of 15 ( im freaking out!) but the motor and tranny are brand new and i used the old knock sensors so you think its the senors frost? i can put up my scan file if you want

[n20kid]

ok i have a camaro with the same problem i just put the motor in im getting solid blocks of 15 ( im freaking out!) but the motor and tranny are brand new and i used the old knock sensors so you think its the senors frost? i can put up my scan file if you want

I would def change the knock sensor's out, i like putting new ones in with a fresh build.. hell i like to put in new 02 sensors when i do the hedder's if the customer can afford to..

[bwkmaro]

could it be anything else you think? at a 15 with out hearing it.. sounds fishy to me im very nervous. but it doesnt knock at all during normal driving either

[blownbluez06]

could it be anything else you think? at a 15 with out hearing it.. sounds fishy to me im very nervous. but it doesnt knock at all during normal driving either

If you want to try a "sanity" check then put some Torco or comparable octane booster in 1/2 tank and back off your timing in the area where it's showing KR. If it doesn't change, then you have a physical problem and not a legitimate knock problem. It can be in the sensors, wiring or something banging around where the sensors are picking up the knock frequency. Did you torque them to spec when you installed the sensors?

[PAT WS6]

im having a similar issue, even tho mine arent exactly in blocks of 4, most of them are 4 but around them will be 4 and 3, any one mind looking at my log?