How To Stop Pre-Detination Rattle?

[ppc]

@ppc
It is constant if throttle held at a specific RPM range. It's from about 1,600-2K slowly accelerating or about 3,800+ when floored.

Just to clarify is the pinging present constantly while accelerating or only the first few seconds?

 

[Azca]

Does it ping when the engine is cold? Air temps when you first hear it?

 

[LFD2037]

@ppc
Just for 1 second. None at all if I floor it from a stop.

@Azca
Does not ping when its cold. Air temps have to be above 85ish. Intake temp above 105ish.

 

[hammerheadfistpunch]

@ppc
Just for 1 second. None at all if I floor it from a stop.

@Azca
Does not ping when its cold. Air temps have to be above 85ish. Intake temp above 105ish.

This sounds like whats happeneing to mine, Im following this thread now. Just had the whole top end rebuilt.

 

[Azca]

Ditto with mine, Octane does not resolve it, timing is good, temps are good. I am going to bring it to one of our local experts to help diagnose. Ping, rattle or knock ends around 1200 RPM (or it is just not audible). Does not begin until engine is at full operating temp and air temps are in the 90s...

 

[hammerheadfistpunch]

Here is some audio I took of mine driving home yesterday, no problem when cold, but as it heats up.

its no the best recording but you can here it as the same noise as the OP

 

[Alleycats]

Maybe if you can get the engine temp. down some or the intake temp. that might help, if not eliminate the problem?

 

[hammerheadfistpunch]

Maybe if you can get the engine temp. down some or the intake temp. that might help, if not eliminate the problem?

Cooling system is basically brand new (new rad, thermostat, waterpump, etc) and so I don't think the engine temps are super high. I was thinking it could be valve clatter (top end recently rebuilt) or piston slap. Im investigating the piston slap right now with some 10w30 I changed in last night, didn't hear it on my commute this morning.

 

[LFD2037]

My temps are good via UltraGauge. Cliff notes:
Doesn't do it cold
Doesn't do it on deceleration
Doesn't do it WOT from stop
DOES do it below 2K RPM from stop
DOES do it above 3,800 RPM WOT
92/93 octane makes it 90% gone
Not smoking
Not overheating
Oil level good
No CEL but 'pending' O2 codes
Started about 2-3 months ago
Does the same at 3* or 6.5* timing
Sounds like marbles in a steel can

 

[1972FJ55]

I've been experiencing this same issue, so I just received the "Amazon" snorkle to see if cooler intake temps will alleviate the pinging. Will post results after installation, hopefully this weekend.

 

[ppc]

@ppc
Just for 1 second. None at all if I floor it from a stop.

@Azca
Does not ping when its cold. Air temps have to be above 85ish. Intake temp above 105ish.

If it is only lasting for 1 second that means the knock sensors input to the ECM is working properly. The bad thing when the ECM drops the timing back it does in large increments which means lower performance and higher fuel consumption.

I'm guessing its because the engine is running lean. That puts carbon buildup, O2 sensors, faulty/dirty injectors, fuel pump and fuel pressure regulator in that order as possible causes.

What happened 3 months ago when this started? Any maintenance that was done or other problems? Does the Republic of Texas switch over to summer blend fuels at that time? If that is the case there may have been a problem starting earlier but the change in blends just made it more noticeable. Has gas mileage dropped?

I would run some Seafoam or BK44 through the engine as a first step to try to clean out the carbon.

 

[hammerheadfistpunch]

My temps are good via UltraGauge. Cliff notes:
Doesn't do it cold
Doesn't do it on deceleration
Doesn't do it WOT from stop
DOES do it below 2K RPM from stop
DOES do it above 3,800 RPM WOT
92/93 octane makes it 90% gone
Not smoking
Not overheating
Oil level good
No CEL but 'pending' O2 codes
Started about 2-3 months ago
Does the same at 3* or 6.5* timing
Sounds like marbles in a steel can

question: do you have the manafold heat shield on or off?

 

[NLXTACY]

question: do you have the manafold heat shield on or off?

Or better yet, is it cracked and loose and now vibrating? What about cat heat shields?

 

[hammerheadfistpunch]

Or better yet, is it cracked and loose and now vibrating? What about cat heat shields?

Actually I was curious because the shop that did my work removed the heat shield and I am wondering if the heat soak off the manafold is causing the issue. Mine is off and I have the same issue.

 

[NLXTACY]

Removing it just makes the AC work harder and raises the air intake temps. I'm sure it will bring other issues as well down the line.

 

[LFD2037]

If it is only lasting for 1 second that means the knock sensors input to the ECM is working properly. The bad thing when the ECM drops the timing back it does in large increments which means lower performance and higher fuel consumption.

I'm guessing its because the engine is running lean. That puts carbon buildup, O2 sensors, faulty/dirty injectors, fuel pump and fuel pressure regulator in that order as possible causes.

What happened 3 months ago when this started? Any maintenance that was done or other problems? Does the Republic of Texas switch over to summer blend fuels at that time? If that is the case there may have been a problem starting earlier but the change in blends just made it more noticeable. Has gas mileage dropped?

I would run some Seafoam or BK44 through the engine as a first step to try to clean out the carbon.

I'm ordering new O2 in the morning. I guess about 3 months ago they changed the fuel blend????? MPG's have not changed.

 

[LFD2037]

Heat shield is in place and does NOT rattle. This isn't a rattle of vibrating metal. 100% sure about that.

 

[Azca]

I've been experiencing this same issue, so I just received the "Amazon" snorkle to see if cooler intake temps will alleviate the pinging. Will post results after installation, hopefully this weekend.

Have snorkle, temps range up to 127 intake, still rattles though...

 

[Azca]

Same here, shields in place. Ran seafoam through mine, again, no changes. I have not tried the fuel filter and for what they cost I am just going to throw new plugs and wires in mine, even though I have less than 12k miles on them...

 

[LFD2037]

I have less than 10K on my plugs/wires/cap/rotor (all OEM).