ECMlink Random Knock Low RPM

[Vdubzr32]

1). Any boost, vac, or exhaust leaks? Boost leak tested 5psi above your max boost with no leaks? YES

2). Verified mechanical timing? YES

3). Verified base timing? YES

4). Ignition system
COP or Stock Coil: STOCK
Wire brand and Age: NGK NEW
Spark Plug brand, type and Gap: BPR7ES .024

5). Motor health (Compression Test)
Cylinder 1:
Cylinder 2:
Cylinder 3:
Cylinder 4:

6). Performed basic throttle body adjustments?
Idle Switch: YES
Throttle Cable: YES
TPS: YES
BISS: YES

7). Compression ratio; 8.5:1

8). Any known bad sensors or brittle wiring? NO

9). Any DTC/CEL codes? NO

10). Electrical system
Car off (not running):
Car running: 13.5

11). Base fuel pressure and injector values
Base Fuel Pressure: 47
Injector Size (cc/min): 880

12). Properly calibrated and configured wideband sensor
Sensor Brand: LC1
Calibration Date: 1 month

13). Type of fuel
Type: 93
Percent of Ethanol: NA

14). Watched ECMlink how-to videos YES


I'm getting random knock at low rpm sometimes while cruising in 3rd or 4th gear on a slight incline or on flat road. on the log you can see at 355 sec. I hit knock which went as high as 3 degree. Am I missing something in the tune or mechanically that can fix this. I've been getting help from "Tony TMONEY20g" awesome guy very helpful but we are both baffled to the fact that knock exist at this point.

Knock sensor is brand new installed when motor was built. I don't get knock on WOT pulls.

 

[tmoney20g]

correction on his plugs, they're gapped at .024" and they look good. another set of eyes on this or some ideas would be great

 

[Vdubzr32]

correction on his plugs, they're gapped at .024" and they look good. another set of eyes on this or some ideas would be great

thanks for chiming in

 

[93'colttsi]

Have you tried dropping the timing in the area where the knock is occurring?

 

[Vdubzr32]

Have you tried dropping the timing in the area where the knock is occurring?

timing was dropped by 2 degrees as per Tony

 

[Vdubzr32]

Anyone else have advice

 

[DroopYeyeS]

I actually have this same issue going on in my '91. I've noticed that I get this right around the 25% - 40% throttle range and always between 2500 - 3200 rpm. only mine has gone as high as 15 degrees. also a new knock sensor. But i can go full throttle at the same rpms, and get no knock all the way to redline.

 

[BoostedBeaver]

The knock you are seeing shows up under non boost (Vacuum) conditions at low load, throttle position and RPM. I suspect that this is phantom knock produced by some noise at that rpm/load range.

I would suggest altering the knock sensor values in the ALS/Knock tab. Try something like 2200RPM and 50% throttle.

 

[jakk220]

Sounds a lot like phantom knock to me as well especially since it doesn't respond to pulling timing. Could be caused by a lot of things such as exhaust leak, lose bolt rattling around, things like that. Mine was an exhaust leak and went away after I fixed it. Those knock sensors are picky...

 

[DroopYeyeS]

I've always wondered if it could be phantom knock, as no amount of tuning changes when and under what conditions it happens. The only change is the amount of timing that gets pulled, and it falls on its face when it happens. The only difference for me is that it does tend to be in low (5-10psi) boost. Not sure if the OP is having this issue as well.