Supercharged 5.7 is backfiring at heavy throttle

But its got a bypass kit

 

The actual numbers, they could be relevant.

 

I have a bully dog tuner made for the SC that I don’t use that you are more than welcome to if it helps you out. Just pay for shipping and you can have it for free.

 

I have a bypass too, there are still permanent codes. Just no CEL.

 

You may also need to verify that the block-off plates are installed, in case the PO tried to cut some corners. They can sometimes be the more difficult aspect of the kit. Any details that can be shared will help, however seemingly unrelated.

 

Code is po419

 

Secondary air injection system control "B" circuit, open in air pump drive circuit.

May be something as mundane as a broken/damaged wire. Honestly, I'm not going to be able to tell you exactly where to poke around other than that this system is on the passenger side in the engine compartment. It might not hurt to make sure that the wiring for the bypass kit looks like it's in good condition and all the connections appear to be sound. Some of the kit connections on my truck are at the coolant temp sensor at the front of the engine, and the MAF sensor on the air intake tube.

 

That’s where my bypas kit runs also and has a harness at the mass air flow

 

I guess that then maybe start taking a critical look at the wiring in the area of the SAIS to see if there's evidence of damage. Sorry that I'm not more familiar with that system to try to narrow things down a bit more. For all I know, that may not even be the next logical place to investigate. Maybe someone who's more familiar with it can make a suggestion. FWIW, I would think that you'll need to sort that out in order to have a go at the other issue.

 

I really appreciate it I have never had to deal with that type system either

 

No worries.

Maybe @Ruggybuggy has time to give your situation a thought. We'll see if he's inclined.

 

Yes, I have a 5.7 SC. Engine produces at least 550hp. Has a Bullydog tune. Had it tested on a dyno. 464hp at wheel with 475 ft lbs of torque. It's very powerful and fun as hell to drive. Check out the dyno video:
https://drive.google.com/file/d/1QckfP_kfOjhG8lK8X4cVAy8Tt6c4IVXt/view?usp=drivesdk

 

Most bypass kits just prevent the pump from running by tricking the IAT sensor into thinking it is too cold outside during the start up. This does not prevent the pump circuit check from being run by the ECM.
Thus, if either of the air pumps or the air pump wiring has an open in it, the ECM will set a P0419 or P0418 code.
To diagnose this, you would need to measure the resistance across the air pump, it should be around 1 ohm.
If the pump has an open in it, you could replace it with a 1 ohm heavy duty resistor since the pumps don't turn on anyways (as long as your bypass kit is functioning properly).
If both pump resistance is good, it is probably a broken/disconnected wire to a pump.

 

Greets Viktor!

I know that I kinda pushed that resolving the code is important, but might you be able to speculate how the code may or may not affect his tune or result in the symptoms he's experiencing, assuming that it's an atypical TRD produced tune?

 

Yes please

 

This paperwork, is it from a Toyota dealership?
Does it backfire through intake or exhaust?

 

Seems like through the exhaust kinda like bogging down

 

And no not from dealership

 

Who?

 

I’m not sure didn’t have a name so I am not 100% sure if it’s legit

 

Is there text on the invoice that describes the work that was done? You may have to find someone that can check your ECU to verify that it was updated to a S/C tune.

 

Sounds like it may be running super rich.
You need to find out what tune is in it.
Normally a TRD tune can only done by the dealership, so if your invoice is from elsewhere, it may be a custom tune.
Was it always running poorly since you got it or did it happen over time?

 

P0419 will not affect how the engine runs.

 

Not entirely true, I was able to download and install the TRD tune using techstream and some cables from a local shop. Not to say I don't agree with everything you're saying, but entirely possible someone else put the TRD tune in it. I know there were a few iterations of the TRD tune too, when I had it my AFR was in the 9s at WOT though never had any issues like OP.

 

For sure, by “normally”, I meant “generally”, but you are totally right, anyone with a techstream can do it.
I’ve also had a number of TRD tunes in my truck and even though the AFR has hit high 9s at times, they have not bogged or backfired.
Maybe the OP has a wrong intake MAF tube on it, causing it to run extra rich?

 

I have an AirRaid intake/tube (had to cut the tube down a solid 6-8" to get it to fit after adding the blower) and never had any performance issues. Again, not saying that's not the issue, but seems unlikely that would affect the truck that much? Maybe it is the spark plugs like a lot of people said, a few months back I started getting a misfire under high load and it turned out it was a spark plug that was only a year old and cosmetically looked completely fine but for whatever reason started shitting the bed.

 

WOW, thanks for the enthusiastic response. Much appreciated

 

Could it be that my bypass to the air induction pump is bad and where is joins into the mass air is giving false readings

 

Check connection...is it a "rigid" integration between main intake trunk and AIP merge pipe? Make sure you're not getting a crack or loose connections...always try the eaiest/cheapest things first...where you're suggesting is where I'd start...