Need help

[joshw4]

I am new to Hp tuners. I have been taking my ultra 4 car to a local shop for tuning but I always leave with the same issue. From idle when you try to go WOT it backfires through the intake. I know this is a lean issue but we have been unsuccessful at figuring out the cause. Here is the tune and a log of the lean backfire.
buggy tune 10.hptbuggy lean backfire 8.28.14.cfg

[10_SS]

I see the .hpt for tune, and .cfg for config... but no .hpl for log file.
what motor, mods? Fule system?

Plus your MAF table doesnt look stock... two big flat spots, one at 8600hz and another at 11,000hz. Usually a bad sign of the overall health of that tune.

[joshw4]

I see the .hpt for tune, and .cfg for config... but no .hpl for log file.
what motor, mods? Fule system?

It is titled buggy backfire 8.28.14 that is my log.
it is a turn key motor ls2 4" bore 4" stroke. I am not sure of the cam. The fuel system is all -8 line regulated to 60psi stock injectors walbro 225 pump.

[joshw4]

I see the .hpt for tune, and .cfg for config... but no .hpl for log file.
what motor, mods? Fule system?

Plus your MAF table doesnt look stock... two big flat spots, one at 8600hz and another at 11,000hz. Usually a bad sign of the overall health of that tune.

What should I do on the MAF table?

[joshw4]

If anyone has a base tune for a drive by cable ls2 stroker from turn key. I think I may have a better chance starting there as I am a rookie. I just purchased HP tuner cause I have not had and luck with the tuners in my area.

[10_SS]

there may be a stock tune in the repository... if it runs good most places you may want to keep it... but your log file is not attached. "It is titled buggy backfire 8.28.14 that is my log." The file you included ends with .cfg... that is the config file... that is the thing that holds all the parameters you are logging.. it's only 5kb. .but it's not the log file. Log file ends in "xx.hpl". Keep looking.. when you click on the log file, it should open up in the scanner and show you the data.

[joshw4]

there may be a stock tune in the repository... if it runs good most places you may want to keep it... but your log file is not attached. "It is titled buggy backfire 8.28.14 that is my log." The file you included ends with .cfg... that is the config file... that is the thing that holds all the parameters you are logging.. it's only 5kb. .but it's not the log file. Log file ends in "xx.hpl". Keep looking.. when you click on the log file, it should open up in the scanner and show you the data.

Sorry here is another log fileBuggy backfire 8.29.14.hpl

[10_SS]

yea it just looks lean everywhere. Your Long Term Fuel Trims are off? I see when it's idling your Short Term Fuel trims start to max out.. in the short time it's idling/logging the short term fuel trims are climbing up past 18%! So for starts your fuel pressure or injector tables could be wrong assuming your MAF/VE tables are somewhat stock... but if you want to just take your entire MAF table and multiply by 15%... (1.15) then that might make it run better right off the bat but this likely isnt the "problem", just a quick fix.

An alternative to that would be reducing what your injectors say they flow by 15%.

You should look into the injector flow rates/pressures, etc make sure all that is right. If you get that right then you may not have to mess with the MAF too much. Looks like it needs some work but it doesnt look that bad.

If they are stock injectors then that part should be easy... just compare injector section to a known stock injector tune. If your fuel pressure is adjustable then that could be off compared to what the tune is expecting. If you can ajust fuel pressure to stock, then that could fix the problem too. Also compare the MAF and VE tables to that of a stock file... should be close.

If it starts good and all that seems right, then you may just want to figure out why the LTFT arent working, and just disable VE, and tune the MAF for now. Usually the easiest fix. Just make sure it starts good after any change you make since if it starts good then that's a good sign injector settings are close..

The reason it's backfiring is because the Short term fule trims likely max out in what they can add... which should never happen (Long term or short term). This just means that it's lean most likely everywhere... including any transients like when you mash the throttle. Increasing fuel pressure 15% may also bring it in line.

[joshw4]

yea it just looks lean everywhere. Your Long Term Fuel Trims are off? I see when it's idling your Short Term Fuel trims start to max out.. in the short time it's idling/logging the short term fuel trims are climbing up past 18%! So for starts your fuel pressure or injector tables could be wrong assuming your MAF/VE tables are somewhat stock... but if you want to just take your entire MAF table and multiply by 15%... (1.15) then that might make it run better right off the bat but this likely isnt the "problem", just a quick fix.

An alternative to that would be reducing what your injectors say they flow by 15%.

You should look into the injector flow rates/pressures, etc make sure all that is right. If you get that right then you may not have to mess with the MAF too much. Looks like it needs some work but it doesnt look that bad.

If they are stock injectors then that part should be easy... just compare injector section to a known stock injector tune. If your fuel pressure is adjustable then that could be off compared to what the tune is expecting. If you can ajust fuel pressure to stock, then that could fix the problem too. Also compare the MAF and VE tables to that of a stock file... should be close.

If it starts good and all that seems right, then you may just want to figure out why the LTFT arent working, and just disable VE, and tune the MAF for now. Usually the easiest fix. Just make sure it starts good after any change you make since if it starts good then that's a good sign injector settings are close..

The reason it's backfiring is because the Short term fule trims likely max out in what they can add... which should never happen (Long term or short term). This just means that it's lean most likely everywhere... including any transients like when you mash the throttle. Increasing fuel pressure 15% may also bring it in line.

I compared the VE tables to a stock ls2 and they are the exact same. I increased the MAF by 15% across the board and it got better but still back fired a little. So I increased it by 10% more and it woke right up. it looks like I still have a issue on bank 2 at idle my STFT gets up to 41% and bank 1 goes between -2 and +1. Maybe a bad injector?

[joshw4]

I am going to invest in a wideband. what do you recommend?

[10_SS]

I am going to invest in a wideband. what do you recommend?

NGK AFX for sure... Rock solid analog outputs.

Something's messed up no question, try swapping all injectors from left to right bank.

We had leaky injectors on a truck, and a leaking regulator into the vacuum tube on a minivan, they both dumped extra fuel into engine and made the stft and ltft go max lean (-25%) only at idle... So ran strange... But maybe yours are clogged...

Suppose it could be an intake leak also... Keep us posted

[10_SS]

I am going to invest in a wideband. what do you recommend?

NGK AFX for sure... Rock solid analog outputs.

Something's messed up no question, try swapping all injectors from left to right bank.

We had leaky injectors on a truck, and a leaking regulator into the vacuum tube on a minivan, they both dumped extra fuel into engine and made the stft and ltft go max lean (-25%) only at idle... So ran strange... But maybe yours are clogged...

If that does 0, maybe try swapping O2 sensors.

Suppose it could be an intake leak also... Keep us posted

[joshw4]

NGK AFX for sure... Rock solid analog outputs.

Something's messed up no question, try swapping all injectors from left to right bank.

We had leaky injectors on a truck, and a leaking regulator into the vacuum tube on a minivan, they both dumped extra fuel into engine and made the stft and ltft go max lean (-25%) only at idle... So ran strange... But maybe yours are clogged...

If that does 0, maybe try swapping O2 sensors.

Suppose it could be an intake leak also... Keep us posted

Awesome thanks for the input. I am going to swap injectors today and see what happens.