2TR-FE back fire since adding magnaflow

Need some help from the 2.7 guys ever since I added my magnaflow I get a backfire almost always when I let off the throttle and get back on it like when shifting and such doesn’t do it all the time but happens frequently enough. Is this just a characteristic of having a aftermarket exhaust?

 

How much bigger is the exhaust you added over stock?

 

It is a 2.5 straight threw offset magnaflow which I believe 2.5 is the stock size.

 

You might be running too rich with fuel or lack of back pressure is causing issues. Might want to throw the OEM exhaust back on to see if the problem continues, and rule out the exhaust causing it

 

It was welded in by a exhaust shop so not so easy to remove. It did not do it before the exhaust was added though.

 

Does it do it after fully warmed up, or only when it hasnt reached and held operating temp?

 

Both

 

Normal DFCO popping on decel. You just hear it now because of the more open exhaust.

 

What is DFCO?

 

this is true ^

On my 2.7 2trfe I had a straight thru cherry bomb extreme did the same thing back fires from hell. It has something to do with the unburnt fuel in the exhaust igniting. The stock exhaust has a cat back like bend for back pressure thus eliminating back fire.

 

Decel, fuel cut off.

 

Deceleration fuel cutoff. It’s part of the tuning of the ECU. At its most simple, when the truck starts to decelerate fuel is cut off. What you are hearing is leftover fuel (stock tune is rich) igniting after the valves.

 

Gotcha

 

All makes sense now thanks. If it is normal am all good with it.

 

I’ve had this problem with a few carb’d and FI motorcycles after adding better flowing exhausts or even just slip-on mufflers.
We always called it ‘after-firing’ because it’s unburnt fuel igniting in the exhaust. ‘Back-firing’ is when it ignites back up through the carb or TB. It’s prob just running too rich since your new exhaust.

Not sure what’s available for the 2.7’s, but I imagine something similar to OVTune could help adjust fuelling for this condition(???) If not, i’ve had luck curing or lessening the after-firing by opening up (ie: getting more air in) the intake end by installing good aftermarket high flow air filters (when re-jetting or re-programming isn’t an option)

BTW- Make sure your current air filter/intake isn’t dirty or restricted in anyway before you do anything else.