Maf issue Ls swapped 73 Camaro

[Hpsonny]

Again thanks for taking a look at seeing stuff that sticks out or advice once again but lets try this again ..

original post:
I'm having a little issue with my dad's Camaro I swapped a 5.3 /4l60 combo in. So, it started to do a backfire through the exhaust on some mild to moderate acceleration. I called my tuner who is somewhat local to me, had my dad drive it down there where they went for a drive re tuned it and fixed its issues he said. My dad drove it home and was going by my house when the problems came back, I drove it and it felt like he didn't do a thing to re tune it however my dad said it was totally fixed when he was there .. only when he came back this way and got off the freeway it started to act up .. When I drove it, it backfires and breaks up but more throttle for a few seconds and over 4k I'd say it clears up and is fine. even on a cold start, same result it and it starts to break up at about 30 to 50% throttle and clears up .. It does throw a Maf code p0101 so i changed the Maf with 3 different ones only to have the same result and code. I disabled the maf in the tune and it runs fine without it breaking up and or wanting to stall when coming to a stop. This log is a short one where i drove it and right after it broke up , i stopped the log. The tune is with me disabling the Maf everything else i didn't touch this is the tuners work . i wanted to note that the tuner said its a mechanical issue and not the tune. The car starts fine idles great , wot is good and drive ablity is good its just that one area for a few seconds that has this weird issue. I noticed that it drops timing plus airflow and goes rich as it start to pull fueling when it does this issue as well. Not sure what else i need to take a look at here..

73 Camaro

5.3 /4l60e 3200 circle d
3.73 gear
112 lsa .580 .580 232/234 @.50
headers
ls1 intake
heads milled .30
corvette filter (changed recently)

Thanks for checking this tune and log out in advance

[gtstorey]

Are the MAF numbers anything like in agreement with the MAP?

[Hpsonny]

Are the MAF numbers anything like in agreement with the MAP?

What should it generally read ?

[gtstorey]

MAP and MAF should generally read the same numbers when put into the same units. Not a single number since it's an air flow measurement, usually discussed in grams/second. If they generally match but occasionally fall out you still have MAF issues, maybe in the wiring/connectors. If they don't generally match, could be a tuning issue.

Or the air intake layout is so bad since this is a swap that there is too much turbulence in the intake and/or with a cam, that MAF isn't going to work and just needs a speed density tune.

[Hpsonny]

MAP and MAF should generally read the same numbers when put into the same units. Not a single number since it's an air flow measurement, usually discussed in grams/second. If the generally match but occasionally fall out you still have MAF issues, maybe in the wiring/connectors. If they don't generally match, could be a tuning issue.

Or the air intake layout is so bad since this is a swap that there is too much turbulence in the intake and/or with a cam, that MAF isn't going to work and just needs a speed density tune.

I see what you mean .. i need to take a look at that and see if they match at all but you bring up a point that i?ve been thinking about a-lot and that?s the maf placement .. It?s right after the 90 elbow that comes off the throttle body then tube then filter . I was thinking of moving it more toward the filter side as it?s about 5? from the throttle body now and maybe trying to get it to about 10? then tube and filter. I do kinda feel it?s turbulent air as this problem occurs in the same spot during the drive all the time ?

[gtstorey]

Probably time to just run it Speed Density.

[2xLS1]

It looks there is a lot taken out of the VE and a lot added to the MAF. That is probably the cause of the P0101 which is a predicted airflow code, not necessarily a bad MAF code. There is a table in the Engine Diag tab you can multiply that whole table by 3 or 4 and get values closer to what the older calibrations use. Overall the tune doesn't look that bad. The odd thing is it looks like they started with an 05 Escalade 6.0L file when you are using a 5.3L. A few things I noticed, the values in the idle airflow table are really high and the cracker is completely disabled, the timing in the idle tables is pretty low and in the HO Timing Table there is a bunch of timing pulled in the mid airflow and rpm area. This is all comparing it to a stock 05 Escalade 6.0L stock file with all the same segment numbers. And you didn't say what the injectors are bit it is set up for something around a 42 lb injector.

[Hpsonny]

It looks there is a lot taken out of the VE and a lot added to the MAF. That is probably the cause of the P0101 which is a predicted airflow code, not necessarily a bad MAF code. There is a table in the Engine Diag tab you can multiply that whole table by 3 or 4 and get values closer to what the older calibrations use. Overall the tune doesn't look that bad. The odd thing is it looks like they started with an 05 Escalade 6.0L file when you are using a 5.3L. A few things I noticed, the values in the idle airflow table are really high and the cracker is completely disabled, the timing in the idle tables is pretty low and in the HO Timing Table there is a bunch of timing pulled in the mid airflow and rpm area. This is all comparing it to a stock 05 Escalade 6.0L stock file with all the same segment numbers. And you didn't say what the injectors are bit it is set up for something around a 42 lb injector.

The computer i have for it is i guess from a 05 escalade and it?s been that way for a while now . I guess from what i?m reading here is maybe i could start playing around with the airflow slightly and timing in that area see if that helps .. Yes they are bosch injectors from a g8 actually 42 lbs

[abc]

Not logging enough data, no rpm trace?
Looks to me like you need to pick a direction to tune first, the VE table looks soft to me. If it were mine, I would put it in SD, get the VE table correct then tune the MAF.

[2xLS1]

If you hadn't said it doesn't backfire and break up with the MAF disabled I would have guessed you have an ignition problem like a cracked plug or two. The symptoms you describe sound like that I did notice that all the misfire tables appear to be stock. You could try logging individual misfiles by cylinder and misfire history per cylinder and see it any particular cylinder or cylinders are causing it with the MAF enabled.

[Hpsonny]

Not logging enough data, no rpm trace?
Looks to me like you need to pick a direction to tune first, the VE table looks soft to me. If it were mine, I would put it in SD, get the VE table correct then tune the MAF.

I?m not 100% sure what to log i just did things i thought needed to be looked at .. And the guy who tuned it had done a few of my cars and does this for a living so i assumed its tune is in the right spot on this one.

[Hpsonny]

If you hadn't said it doesn't backfire and break up with the MAF disabled I would have guessed you have an ignition problem like a cracked plug or two. The symptoms you describe sound like that I did notice that all the misfire tables appear to be stock. You could try logging individual misfiles by cylinder and misfire history per cylinder and see it any particular cylinder or cylinders are causing it with the MAF enabled.

That was the first thing i looked at were plugs then noticed the wire was melted so i changed them both. With the Maf disabled , it runs ok and no hiccups /breakups

[bk2life]

Your PE is set to come on at 15kpa, and the PE added is set 'flat' across the board from idle to limiter

If you have hptuners, id fail the maf, and get a good log of the actual VE table, spark advance, retard, and adjust as necessary.
then turn maf back on and log it.

Your tuner has a few things set differently then i would.

But also for thought, thats a big cam, you might want to go full time speed density

[Hpsonny]

Your PE is set to come on at 15kpa, and the PE added is set 'flat' across the board from idle to limiter

If you have hptuners, id fail the maf, and get a good log of the actual VE table, spark advance, retard, and adjust as necessary.
then turn maf back on and log it.

Your tuner has a few things set differently then i would.

But also for thought, thats a big cam, you might want to go full time speed density

I believe i failed the maf and able to drive it without it breaking up or backfiring. I have a log of it with maf enabled as well just not with the maf disabled but i can log it without the maf and see what happens .. Yeah i have heard to go S D but won?t i need the intake temp sensor ?

[2xLS1]

You don't have to actually remove the MAF to run in SD. You can just fail it and leave the IAT in place

[SiriusC1024]

Engine>Torque Management>General>Transmission Torque Mng.>Max Torque is 640. That value exceeds max. ECU does weird things when max values are exceeded, and your original problem statement sounded like torque intervention.
max tq value.png

Put in 639.

Hell all the values down that transmission torque management column exceed max. Maximum Torque>RPM vs. Gear, too. Fix them.

[Alvin]

This would do better in speed density. Driveabilty should improve without a MAF.

[Hpsonny]

Engine>Torque Management>General>Transmission Torque Mng.>Max Torque is 640. That value exceeds max. ECU does weird things when max values are exceeded, and your original problem statement sounded like torque intervention.
max tq value.png

Put in 639.

Hell all the values down that transmission torque management column exceed max. Maximum Torque>RPM vs. Gear, too. Fix them.

Ok let me change those to that lower number and go from there . Is there a reason why this was changed to 640?

[Hpsonny]

Ok let me change those to that lower number and go from there . Is there a reason why this was changed to 640?

I changed the values to 639 so ill load this up and see what it does in the next couple of days .

[Hpsonny]

I ended up driving my dads Camaro today with no good results as it breaks up / backfires through the mufflers under moderate acceleration and wants to die when the maf is enabled coming to a stop .. Maf disabled drives much much better and barely barely breaks up, won?t stall slowing down to a stop . I have enabled and disabled the maf today and moved my torque numbers like Sirius said to change with no gain in fixing this .. Im at a loss because the guy who tuned it said it?s ?mechanical? plus you guys have looked over the tune with not seeing if anything sticks out.changed out 3 mafs same issue .I feel it?s in the tune where the tuner says it?s not but physical .. He knows more then i do there so i can?t argue but i have no idea what else i need to do to get this car happy. Idle great , part throttle not great , Wot great. Tune is same as posted and the short log is where it breaks up then stopped the log right after .. As noted it drops timing loads up with fuel and looks like it looses maf air at that time in the log file