Pinging under load need help

[ja_racing]

Just drove it and its in closed loop when pings

[ja_racing]

3 hours ago, Ωhm said:

When pinging occurs is ECU in OPEN LOOP (OP) or CLOSED LOOP (CL)?

Closed loop

[Ωhm]

Odd it finds knock during WOT, yet no knock control, while in CL, for the other modes of driving.

[ja_racing]

2 hours ago, Ωhm said:

Odd it finds knock during WOT, yet no knock control, while in CL, for the other modes of driving.

No knock at wot 

the knock/ping is cruising at 35-45 and wanting to accelerate a bit to pass a thats when it pings and timing is above 40 during these conditions 

 

i have a spare ecu thinking about trying it see what it does with spare ecu i don't know what else i can check 

[Gojira94]

No knock at WOT is probably because it's essentially going into OL briefly, in power enrichment mode. PE Ignores O2 feedback and ramps in extra fuel. PE "attack" has a period defined in the ECM probably in milliseconds, where it ramps up from a little extra fuel to quite a bit more, probably over the course of about a second and a half. When you lift, it exits PE and returns to looking at closed loop qualifiers and goes back into CL as soon as they're met (probably over about 3-4 seconds). While it's doing that, PE "decay" is dialing back the fueling to normal, for part-throttle driving. 47* of advance is a LOT. Lean fuel/ air charge requires more time/ advance to burn. If it's running like that all over part throttle, you may just be a little lean across the board. If by chance you have an adjustable FPR, you can bump it up a pound, maybe two and see what the change to part throttle timing might be.

 

Knock can be caused by a lean condition (think mini lean misfires), or pre-ignition/ detonation. Ghetdjc320 mentioned loose quench. That, or head gasket bore being too large can cause pockets of heat to build up at the outer edge of the combustion chamber in the tiny gap between the head and block. Ideally that area has the head gasket fire ring not recessed too far between head and block. Ideally, quench should be in the range of .038" - .045" but as long as the fire ring size is good, a lot of OEMs get away with quench as loose as .060" - .070" with no issues. In that range, you're mostly losing air velocity and chamber burn efficiency, and requiring more timing advance to complete the burn of the air/ fuel charge by 12-14" ATDC. Our engines are at the loose end by default, and have inefficient chambers. Half of quench calculation is the deck clearance, how far the distance the piston is in the hole below the deck. Ours is about .030" with a 6.125" rod and factory deck height of 9.450" - 9.456." So with a common .040" compressed thickness head gasket, quench is around .070." If we open up the bore, we might have to find a gasket with a larger fire ring diameter, and this is when we have to be careful. Fire ring diameter has to be larger than the bore, but not by much. Fire ring diameter .030" - .050" greater than cylinder bore is what we want to shoot for. I'm reading your specs as a 293.68CI / 4.8L, with a 4.2L crank and 4.0 rods, no overbore. I'm guessing you chose a factory style head gasket (probably ideal) and the block hasn't been decked. If the head gasket is something different with a larger fire ring, that can aggravate the conditions you're seeing.

 

Fire ring too big, deep recess between head and block:

 

            /          head

| here              gasket

======          block

 

 

Fire ring sized right with acceptable quench:

 

          /            head

        |              gasket

      ==             block

 

Fire ring sized right with loose quench:

 

          /            head

        | here     (thicker

        | here     gasket)

      ==            block

 

 

As for the knock sensor wiring stuff, have a look at this thread. Important details about the wiring and shielding of the knock sensor connector, particularly post #4.