Backfires while going WOT?

[Msfitoy]

I only use WOT when necessary, such as shooting for a gap to merge in traffic. Recently, I've experienced backfires at full throttle at over 5k RPM...not misfires, but audible muffled pop pop pop from back of exhaust while accelerating hard. Didn't give it much thought as I was about to replace my plugs anyway. Fast forward, month later, I needed to go WOT and heard the same backfires again.

Anyone have a lead on this type of issue? I've heard tightening plug gap down to .028 helps...replace coils...IC weep hole etc...I've had to do a muffler delete recently due to rusted muffler which makes everything more audible...I'll check for codes next...

Otherwise, everything seems to be running normally...

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[confused]

Take a video we want to hear it

 

[My12SecRanger]

sounds like a small exhaust leak to me, but would like to hear a video of the noise

 

[TJC]

Or lack of back pressure due to muffler delete

 

[airline tech]

If I understand correctly - it started after the muffler delete.
The backfire is from the now changed air fuel ratio and is unburned fuel burning in the exhaust.

You may try a (KAM) reset - this will force a new idle air trim learned value as well as tightening the gap of the plugs.
Basically you have taken away some back pressure that the muffler was producing in the air fuel balance.
Another would be to have a tune set for the muffler being removed.

 

[Msfitoy]

If I understand correctly - it started after the muffler delete.
The backfire is from the now changed air fuel ratio and is unburned fuel burning in the exhaust.

You may try a (KAM) reset - this will force a new idle air trim learned value as well as tightening the gap of the plugs.
Basically you have taken away some back pressure that the muffler was producing in the air fuel balance.
Another would be to have a tune set for the muffler being removed.

Interesting...I hadn't thought about how muffler delete would affect the state of tune...I currently don't use a tune and would prefer to stay stock...what is a KAM reset?

In your opinion, @airline tech , is this backfire harmful in any way?

 

[Msfitoy]

KAM, keep alive memory...

 

[Chris M]

KAM, keep alive memory...

And in my head I immediately heard "Stayin' Alive" by the Bee Gees.

Im sorry.

 

[DukeCanBuildit]

Get a BOV and then be on and off the gas all the time. You’ll be the envy of all the cool kids down at the AutoZone parking lot.

“Hey, everyone, here comes Sid!”

Pssshh, pakka, pakka, pakka, pak.
Pssshh, pakka, pakka, pakka, pak.
Pssshh, pakka, pakka, pakka, pak.

 

[airline tech]

Yes - (KAM) Keep Alive Memory
I like to do it with a scan tool, but it is the same as disconnecting the battery for a (length of time???) as the modules will hold some residual power - normally about 15 minutes or so.
some techs suggest to (touch the disconnected battery terminals together) to drain off that residual power or place the headlight switch to headlight position and drain it through the switch.
(Power - Ground)

I prefer the scan tool method.

The KAM Reset - resets all adaptive learning in the PCM, such as Fuel Trims, Idle Trims and Emission Monitors - so its best not to do the reset, just before a state emission's test as the emissions monitors take some time driving for them to run.

The Good or BAD (depending) is that the Transmission Adaptive Learning will also reset. good if it has learned bad behavior, the bad is it will take some time to learn the new shifting strategy and may show some rough shifts at first.

Basically it would be the same as if you just drove the new truck off the lot with a few miles on it.
and the KAM Reset, may hopefully adjust the fuel delivery to account for the unrestricted airflow, in a way you have created a tune adjustment that the engine is not adjusting for and the KAM reset should adjust for that exhaust flow difference it is reading from the Exhaust Pressure Sensor

The relearning process is mostly automatic, however Idle Trim while can be auto learned.
It helps to get the base adjustment by:
Idle for 15 Minutes
Place in (N) - AC- ON / AC-OFF
Place in (D) - AC-ON / AC-OFF
The manuals do not specify times for each position, I have always used a few minutes in each position for the other vehicles I have done. I have yet to do the Ranger, I have thought about it just to see if I could get any noted difference in how the truck drives (No issues-just curious) if the MPGs would increase any. I am holding in the 19-21 MPG range and curiosity has me wandering if I could increase it a tad by resetting KAM.

With that said, sometimes a KAM Reset will create a very high idle at first, first few minutes of start until it leans the new idle trim.

 

[NotBudule2]

And in my head I immediately heard "Stayin' Alive" by the Bee Gees.

Im sorry.

Damn you !!!

 

[TxOTRRanger]

And in my head I immediately heard "Stayin' Alive" by the Bee Gees.

Im sorry.

Good call!

 

[DukeCanBuildit]

Damn you !!!

 

[NotBudule2]

It's not happening , I cant sing that high...

 

[Msfitoy]

And in my head I immediately heard "Stayin' Alive" by the Bee Gees.

Im sorry.

Yeah...looks like most of us are Boomers lol...

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