Issue with back firing

[06_apex]

Stumped. I bought a 2022 with the multi tune turbo dymanics tune with the dash flash. Upgraded clutches, intake, blow off valve, fuel pressure regulator, Has all the goodies. I’m running the 285 tune. When I hit the throttle once I hit between 7000-7300 rpm it backfires shooting flames and falls on its face and spitsand sputters. The dealer said they put a new fuel pump on it and took the closed loop out of it. But there is no change. Does anyone any thought what to look for. Is it fuel, is it over boost, or clutch set up etc. any help would be appreciated

 

[fatchance]

Not sure why they would remove closed loop unless there wasn't all the contributing components in place. Closed loop should help minimize rich conditions. Do you have an AFR module in the sled? What are your AFR's? Was it an adjustable FPR and if so what was key on pressure? What is in it for exhaust.....Muffler, Header? Sounds like it was too rich and fouled the plugs.

the more info the easier it would be to determine what's going on.

 

[sideshowBob]

You need to data log! Only way to sort this out.

 

[KnappAttack]

Sounds like it's hitting the boost cut to me. Is this at part throttle or full throttle? I don't know much about TD tunes, but a call to them and data logging would sort this out.

 

[06_apex]

So we did some testing on it. We are getting no afr reading. When sled is running and it reads 0.6 boost at idle. 46 psi fuel also piped no header and has a 3 bar sensor

 

[Fleecer]

Sounds like a lean fueling issue to me. As Fatchance has suggested, data logging would help isolate the issue.

A fueling issue with closed loop enabled, the data log would show the fuel pump operating at 125%, indicating the fuel pump can't keep up and a lean issue. In addition, I would be willing to bet that the popping shows AFRs of 25 due to the lean condition.

I've had FPRs go bad, and strangely, when they do, can ruin a fuel pump in 40-50 miles. The pump will get abnormally noisy after the sled has been run for 15-20 minutes. In my experience, when they get noisy, they can't furnish. Keep in mind, many pumps are Chinese knockoffs and are junk. Be careful when buying.

In addition, the noisy pump and/or your lean fuel issue could be due to air being introduced into the fuel system. Make sure there are no leaks in the ascending unit and hoses which house your pump/slipper and fuel socks.

What does the gage on the FPR read while the sled is idling? If running closed loop, I would set it at 50#. Better off to have the system pull fuel then add.

When you shut sled off, what does the gage read on the FPR gage? Does it maintain some pressure and slowly drift to 0 after an hour, or does the gage go to 0 right away? Going to 0 right away could indicate a bad FPR.

If you don't want to datalog and want to rule out the FPR, you could put a new high volume pump, go back to the factory fuel pressure regulator and test. At 285hp and good fuel, you can/could run sled with stock FPR to verify if condition improves. If the misfire goes away, your FPR is/was bad.

Just my 5 cents......

 

[Turboflash]

What do you mean by "they took the closed loop out?" How can they remove part of closed loop like that?! None of the closed loop tunes will run with some of the inputs (AFR, TPS, barometric pressure, coolant temp, etc.) missing.
They can't just take one out and expect the engine to run right. Closed loop is "all or nothing" meaning it has to have all the inputs it's looking for or it won't run right.

 

[Fleecer]

So we did some testing on it. We are getting no afr reading. When sled is running and it reads 0.6 boost at idle. 46 psi fuel also piped no header and has a 3 bar sensor

Are you running a header tune with stock exhaust manifold? If so, you are hitting the boost cut. Powertrail at 285hp is a header tune.

 

[Turboflash]

So we did some testing on it. We are getting no afr reading. When sled is running and it reads 0.6 boost at idle. 46 psi fuel also piped no header and has a 3 bar sensor

0.6 boost at idle is not normal.

 

[Fleecer]

What do you mean by "they took the closed loop out?" How can they remove part of closed loop like that?! None of the closed loop tunes will run with some of the inputs (AFR, TPS, barometric pressure, coolant temp, etc.) missing.
They can't just take one out and expect the engine to run right. Closed loop is "all or nothing" meaning it has to have all the inputs it's looking for or it won't run right.

With a flasher, you can disable Closed Loop. Doing so, means adjusting the FPR manually according to different temperatures. Which is how we did things before closed loop was invented.

 

[Fleecer]

0.6 boost at idle is not normal.

TD tunes, I believe .2 - .8 of boost at idle is normal. Anything outside of that would indicate bad map sensor.

 

[Turboflash]

With a flasher, you can disable Closed Loop. Doing so, means adjusting the FPR manually according to different temperatures. Which is how we did things before closed loop was invented.

Did the dealer have flasher?

 

[Turboflash]

TD tunes, I believe .2 - .8 of boost at idle is normal. Anything outside of that would indicate bad map sensor.

Did not know that. Thank you. Mine reads .1 at idle. PEFI Stage 4.