Backfires while going WOT?

[Msfitoy]

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.

I have one...just can't ever hear it inside...

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[TxOTRRanger]

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

Not a boomer, Dad is, it seems like we all have the same warped sense of humor though.

 

[NotBudule2]

Well you can tell by the way I drive my truck
Ive got the pedal to the floor, no time to talk
Turbo loud and engine warm, when i kick it down , a star is born

But now it's not right, it's not okay
It just back fired yesterday
And now to help us understand
It's Airline Tech and he's the man !

Whether you're a brother or whether you're a mother, keep the memory alive, memory alive
If you feel the Ranger breakin' and the engine starts shakin',
Check your memory alive,memory alive
Ah, ha, ha, ha, memory alive, memory alive,
Ah, ha, ha, ha, check your memory ALIVE!

(Blame Chris, he's at fault here, NotBudule)

 

[LB'sTremor]

we oops I mean the too cool kids we called them the squeegees

LB

 

[Msfitoy]

Well you can tell by the way I drive my truck
Ive got the pedal to the floor, no time to talk
Turbo loud and engine warm, when i kick it down , a star is born

But now it's not right, it's not okay
It just back fired yesterday
And now to help us understand
It's Airline Tech and he's the man !

Whether you're a brother or whether you're a mother, keep the memory alive, memory alive
If you feel the Ranger breakin' and the engine starts shakin',
Check your memory alive,memory alive
Ah, ha, ha, ha, memory alive, memory alive,
Ah, ha, ha, ha, check your memory ALIVE!

(Blame Chris, he's at fault here, NotBudule)

Ahhhh....memories...

 

[Bertie321]

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...

I think you answered your own question..
Muffler delete
Without a muffler you will hear what an engine does

 

[skrumpe]

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

or at least Gen X. I saw that movie when it came out and I would have been 5 at the time.

 

[Msfitoy]

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.

Thank you for your very precise description...your depth of knowledge is most appreciated...this fuel trim adaptation is connecting some dots now...I recall immediately after the muffler delete, the truck dropped 1-2mpg...probably too rich of fuel trim...I'll need to add AF gauge to my OBD display and see where it's at...then do a KAM...

 

[Motorpsychology]

Ahhhh....memories...

 

[WSD42]

One more for the solutions...all potentially valid. But add fuel type.. 87, 89, 91, etc. Is your choice a top tier fuel...quality. I was having issues similar to yours, stumbling on WOT or semi hard acceleration. Was getting fuel at BJs (mid tier fuel) then back to Costco (upper tier fuel). Solved our issues on both 2019 Lariat Rangers. Still plan to remove plugs for anal check...lol 28k+ and 32k+ on them. Also need to clean air filter on one with Roush CAI. Plan to install one on the other. Will be interested in your outcome and trouble shooting solution. Cheers...

 

[RedDakooter05]

So your engine is finally going to join your oe transmission in the afterlife eh?

 

[TJC]

I think you answered your own question..
Muffler delete
Without a muffler you will hear what an engine does

You are getting oxygen moving up the opened exhaust at the same time the lack of back pressure is allowing gases to flow faster through the catalytic converter, which no longer has the time to efficiently covert the unburnt combustibles.

A long time ago before catalytic converters, that popping was quite common with big free flowing exhaust systems. FWIW, backfires come up through the intake track out of the carb. Remember the burned eye browse!?! (I do). That burbling is fuel mixing with O2 in the exhaust. Way back when, we worried about bent valves from cold air making it way up the exhaust track cooling the valves too quickly. All from free flowing exhaust systems (or no exhaust systems). Add some restriction (muffler) and problem is solved.

 

[Msfitoy]

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.

One more thing...if I did nothing, would the fuel trim automatically adapt over time?

 

[airline tech]

although yes the PCM may relearn on its own, you have altered something that the PCM may not account for as its looking for (As-Stock) parameters and may continue to adjust fuel trims as if the muffler was installed.

Basically what I (THINK) may be happening is that the O2 Sensors are seeing a faster exhaust flow and its interpreting that as a higher oxygen reading - so the PCMs reaction is to increase fuel delivery (+ Fuel Trims) - so inducing a False Lean condition and the PCM is adjusting and adding more fuel than it actually needs.
So my theory for the KAM reset is to allow the PCM start from a new normal, it may or may not help with the backfire, but will at least force a new learning curve for base values on the trim tables.

I never got into Tuning - so a tech who does tuning and knows the PCM parameters better than I do could shed a deeper explanation that I can, I just know that when something is replaced or altered that alters engine performance and fuel trim tables - its recommended to do a KAM Reset and let the PCM learn new values.
The Main Ones being - The LTFT and Idle Air Trims, The STFT's are adjustments to the LTFT's - Long Term Fuel Trims and Idle Air Trims are stored into the PCMs fuel trim memory tables. The STFT - Short Term Fuel Trims are quick on the fly adjustments to the LTFTs and are reflected in the LTFT tables.

 

[Colo_Ranger]

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

not with that attitude.

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