Turbo 5.3 4L80 Swap encounter Knock Sensor Low Circut Issues

[phtcbra]

LM7 5.3 Swapped 66Nova
GT45 Turbo, 4L80E w/Ford 9" 3.00 gears
91 Octane, OEM GM L96 50 lb injectors with Blind squirrels GEN4 injector data
Frozen Boost A2W intercooler
P59 HPTuners 2Bar SD MOD ECU (ECU is same one from engine vehicle donor)
Stock front O2 sensors are still in use
Innovate LM-2 Wideband
DBW Throttle with deleted MAF, IAT sensor relocated in truck manifold
OEM ACDelco Truck 19418810 2BAR Map (Purchased from Summit Racing new)
Adjustable FPR vacuum referenced (unplugged reference base is 58PSI)
2600 lb street car

I had a previous thread: https://forum.hptuners.com/showthrea...ity-2BAR/page4 and got a lot of help dialing in a drivable tune. Well, I now have a 4L80 swapped in and wired up and all is well. I cleaned up some of the tune over the last few months, but still have to dial in things and am now getting into tuning in boost and keep having the same issue.

Trouble Codes:
P0102 - Mass or Volume Air Flow A Circuit Low (Pending, Current) - From Speed Density
P0103 - Mass or Volume Air Flow A Circuit High (Pending, Current) - From Speed Density
P0327 - Knock Sensor 1 Circuit Low (Bank1) (Pending, Current)
P0332 - Knock Sensor 2 Circuit Low (Bank 2) (Pending, Current)

When I went through the motor, I installed a new Knock Sensor Harness and Knock Sensors from Dorman and this problem occurred. I checked the resistance with a Fluke 87V and then tested the pick up of knock with the hammer test and all seemed fine, but the codes kept coming back. It is throwing the car into REP mode, or LIMP mode.

I then decided to go to DELPHI Sensors, and a relocation kit to try and see if the sensors/harness was my original issue. Picked up DELPH sensors from Rock Auto, installed ICT knock sensor relocation mounts and Torqued the Knock Sensors to OEM Specs. 15 ft LBS.

Problems still exist/persist. I am conservative on my timing and not seeing any knock, just wondering if anyone has any suggestions or can see anything glaring?

Thanks.

130254.hpl

NOVA Tune 2BAR MOD 13025 4L80E.hpt

[Alvin]

Are you trying to use GEN 4 knock sensors on a GEN 3?

That ECM/engine would have had the knock sensors in the valley cover. Torque is very important on them.

Outside that.. this can be a real bear to fix sometimes. Even with all new parts you'll have reoccuring issues with this. Sometimes anyway. I've heard disabling the diag for the knock sensors can still allow them to work.

When those codes are present, often the PCM will pull max timing as a default anytime you go into PE. your log never went into PE so I can't say that is the case.

[phtcbra]

Are you trying to use GEN 4 knock sensors on a GEN 3?

That ECM/engine would have had the knock sensors in the valley cover. Torque is very important on them.

Outside that.. this can be a real bear to fix sometimes. Even with all new parts you'll have reoccuring issues with this. Sometimes anyway. I've heard disabling the diag for the knock sensors can still allow them to work.

When those codes are present, often the PCM will pull max timing as a default anytime you go into PE. your log never went into PE so I can't say that is the case.

GEN 3 Sensors are being used. Delphi AS10017 is what was just installed with an ICT Billet relocation kit.. Was in an attempt to troubleshoot the original DORMAN 926084 harness and sensors installed down in the valley pan that were throwing the same code. Torque was 15 FTlbs, verified few times over..

Right about the time I think I should be entering PE is when the REP occurs, it's like clockwork almost.. Pulling the manifold and installing the new Delphi Sensors isn't out of the question, I just wonder why the same exact scenairos occur with different new parts in different configurations.

Screenshot 2025-01-31 101941.pngScreenshot 2025-01-31 102231.png

[Alvin]

There wouldn't be REP associated with this code. If its going into reduced power something else must be tripping. Usually throttle body/pedal or map / airflow codes will cause that.

[pdsq98gt]

I have run into this a few times on the knock sensor codes. Even with brand new sensors getting both knock sensors low codes. Everything checking out wiring wise. I think there is a minimum threshold we don?t have access to in hptuners. The problem is that it defaults to maximum knock retard when you enter PE. I just set them to ?no error reported? so it doesn?t set the code. The knock sensors still work and will retard timing when they see knock, but it won?t automatically take away 8* when you go WOT.

[dunnjrallen]

I had a REP problem when trying to get into boost and it was Calc Airmass in the Engine Diag-Airflow tab.

[phtcbra]

There wouldn't be REP associated with this code. If its going into reduced power something else must be tripping. Usually throttle body/pedal or map / airflow codes will cause that.

So I am miss-assigning what is occurring when the codes generate and show pending, but yes, the timing is being pulled 8 DEG causing the car to fall on its face, and I need to reset the MIL/DTC codes.

[phtcbra]

I had a REP problem when trying to get into boost and it was Calc Airmass in the Engine Diag-Airflow tab.

I recall trying to edit this out from occurring during the first round of troubleshooting the problem. I currently have my base settings the same as stock, for the boosted tune.

Was this for a REP specific problem or Knock Sensors Circut codes? TIA

Screenshot 2025-01-31 160926.png

[phtcbra]

I'll look further into this.. would love to keep everything working like it should, so I'll take another look at the wiring/setup of everything.

[Alvin]

So I am miss-assigning what is occurring when the codes generate and show pending, but yes, the timing is being pulled 8 DEG causing the car to fall on its face, and I need to reset the MIL/DTC codes.

The 8 degrees out isn't what most people think of as REP. When the dash shows Reduce engine power you might only have 5 % of total available power. Not enough to drive on.

[phtcbra]

Yes, this is exactly what is occuring.

Well, I did some more troubleshooting and I am getting the right data/resistance/AC Voltage to the ECU.. So now I am stumped.

If anyone has any suggestion or ideas Im open to them.

[2xLS1]

Set the codes to NER. The sensors will still work at actually detecting knock in their original location. If you relocated them somewhere else then I would say it's a crap shoot.

[abc]

I recall trying to edit this out from occurring during the first round of troubleshooting the problem. I currently have my base settings the same as stock, for the boosted tune.

Was this for a REP specific problem or Knock Sensors Circut codes? TIA

Screenshot 2025-01-31 160926.png

Yes, this is a problem. Raise this to 3.0 g and get it out of the way for now. This won't fix your knock sensor issue but it very well may solve your REP issue.

[phtcbra]

Set the codes to NER. The sensors will still work at actually detecting knock in their original location. If you relocated them somewhere else then I would say it's a crap shoot.

I tried this, and still have the issue.. So I'm starting to think that my issue is not actually knock sensor related.. I am going to double check but the last few logs where I entered the "REP" -8deg timing pull safety the codes DO NOT SHOW in HPTuners.


Also, I still have my original Knock Sensors installed, so I can swap back to them with just a flip of the plug on the manifold. I may try this and see what occurs. Thank you for the suggestion, its got me thinking.

[phtcbra]

Yes, this is a problem. Raise this to 3.0 g and get it out of the way for now. This won't fix your knock sensor issue but it very well may solve your REP issue.

The entire Graph or just the first box? Have a feeling its the whole box but just want to make sure.

TIA

[2xLS1]

I tried this, and still have the issue.. So I'm starting to think that my issue is not actually knock sensor related.. I am going to double check but the last few logs where I entered the "REP" -8deg timing pull safety the codes DO NOT SHOW in HPTuners.


Also, I still have my original Knock Sensors installed, so I can swap back to them with just a flip of the plug on the manifold. I may try this and see what occurs. Thank you for the suggestion, its got me thinking.

As already stated, knock sensors have nothing to do with REP. REP is a fail safe for the ETC system. You have 2 separate issues.

[phtcbra]

As already stated, knock sensors have nothing to do with REP. REP is a fail safe for the ETC system. You have 2 separate issues.

Yes, agreed. Im not sure how to describle the -8 DEG Safety that occurs, I keep calling it "REP" when it is not Reduced Engine Power mode.

First log and test drive out the issue did not occur of -8 DEG Timing Safey with the Calculated Airmass adjusted to 3.00g so this means progress..

[phtcbra]

I had a REP problem when trying to get into boost and it was Calc Airmass in the Engine Diag-Airflow tab.

So I've been poking around the tune, and it seems that this was they Key to BOTH issues. I no longer am running into the -8DEG timing scenario that was occurring, and then also, after editing the CALC AIRMASS value and drove around a few time I have had ZERO problem.

So, HTH someone. Both the issues are now gone..