MAF Frequency on throttle tip in

[Torinate]

Hello everyone.

As I still struggle to problem solve the 2 issues I’ve got, I’m seeing something odd (maybe?) with the MAF hz when I step in the gas. When I go from idle to throttle, my MAF will rise then drop then rise again again. So I see the increase in airflow then a drop then a rise again.

So, for the PD blower guys here, what are you seeing in logs? Do you see a steady climb in the MAF hz or do you also see the rise drop rise?

I guess it it could be any blower or even NA.

Have any logs you could send showing me what yours is doing?

So if this is the issue, what do you make of it?

Ideas?

Thanks for the help!!

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[horsepower addiction]

what tuning platform?

 

[Torinate]

what tuning platform?

I’m not sure what you mean?

Tuned by Lund. I’ve had a look on live link and datazap and some has looked on vlm scanner.

Car has a hesitation on throttle tip in and an idle misfire. Can’t really feel the misfire but hear the exhaust pop randomly and can watch misfires in Forscan. Occasionally a single “backfire” (only once though) on throttle closed decel. Logs are .csm through an nGauge.

Hope that helps…

 

[Proshop]

I’m not sure what you mean?

Tuned by Lund. I’ve had a look on live link and datazap and some has looked on vlm scanner.

Car has a hesitation on throttle tip in and an idle misfire. Can’t really feel the misfire but hear the exhaust pop randomly and can watch misfires in Forscan. Occasionally a single “backfire” (only once though) on throttle closed decel. Logs are .csm through an nGauge.

Hope that helps…

I think he was referring to like HP tuners or SCT etc etc. Maybe @engineermike may be of some assistance with this.

 

[Torinate]

I think he was referring to like HP tuners or SCT etc etc. Maybe @engineermike may be of some assistance with this.

Gotcha!

Wonder if the tuning platform would make a difference though. Would the platforms not utilize the same values for each? I don’t know enough about the differences to say.

Hoping someone has a little insight if the dip in MAF is normal or if this is indeed an issue.

@engineermike has been quite helpful already. Smart guy…

 

[Proshop]

Gotcha!

Wonder if the tuning platform would make a difference though. Would the platforms not utilize the same values for each? I don’t know enough about the differences to say.

Hoping someone has a little insight if the dip in MAF is normal or if this is indeed an issue.

@engineermike has been quite helpful already. Smart guy…

Anything is possible and yes Mike definitely knows his stuff or maybe even @markmurfie can chime in he does a lot of tuning also.

 

[markmurfie]

On tipin there is potentially a brief spike in MAF Hz from the air rushing in filling the manifold, not all of that contributes to cylinder filling. During this brief period the ECU will use the manifold filling model and speed density to correct the MAF lb/min value to obtain a more accurate in cylinder air mass and fuel mass. Theres a similar non-steady state in the manifold when a tipout occurs.

If you are still having an idle miss and a stumble off idle I don't think this small and brief open loop fuel correction is the problem.
All I have seen was datazap logs from July, 8-9 months ago. I did not see anything that would indicate a miss at idle or other wise. The latter half of the data and labels seem to be matched up inproperly in both those logs. What I assumed the hesitation was looked to be a slow 1-2 shift, not typical of a partial throttle shift. If you are not getting check engine codes or seeing the check engine light blink randomly, I don't think the idle miss is an issue or the hesitation is a miss.
I would be inspecting the fluid quality and its level in your transmission. This has to be done with the engine and trans hot. Engine running, car needs to be raised but remain level for accuracy. best done in a lift. Remove the hex cap and a short dip stick will be inside that you basically burn your hand on the passenger side exhaust while removing is used to check the level. You don't want to be underfilled or over filled as both can cause the transmission to shift poorly. If your level is good you might have excessive clutch wear(C clutch for the 1-2 shift). There will be lots of clutch dust in the fluid or it may even smell "burnt" like brake pads.

 

[Torinate]

On tipin there is potentially a brief spike in MAF Hz from the air rushing in filling the manifold, not all of that contributes to cylinder filling. During this brief period the ECU will use the manifold filling model and speed density to correct the MAF lb/min value to obtain a more accurate in cylinder air mass and fuel mass. Theres a similar non-steady state in the manifold when a tipout occurs.

If you are still having an idle miss and a stumble off idle I don't think this small and brief open loop fuel correction is the problem.
All I have seen was datazap logs from July, 8-9 months ago. I did not see anything that would indicate a miss at idle or other wise. The latter half of the data and labels seem to be matched up inproperly in both those logs. What I assumed the hesitation was looked to be a slow 1-2 shift, not typical of a partial throttle shift. If you are not getting check engine codes or seeing the check engine light blink randomly, I don't think the idle miss is an issue or the hesitation is a miss.
I would be inspecting the fluid quality and its level in your transmission. This has to be done with the engine and trans hot. Engine running, car needs to be raised but remain level for accuracy. best done in a lift. Remove the hex cap and a short dip stick will be inside that you basically burn your hand on the passenger side exhaust while removing is used to check the level. You don't want to be underfilled or over filled as both can cause the transmission to shift poorly. If your level is good you might have excessive clutch wear(C clutch for the 1-2 shift). There will be lots of clutch dust in the fluid or it may even smell "burnt" like brake pads.

Thank you very much for that. I will certainly look at the transmission fluid and do a change.

There is a miss at idle though. I can watch Forscan mode 6 and when I hear the pop at idle the misfire will register. It’s random, but it’s definitely there. % wise it’s not high enough to trigger a cel and it’s random by cylinder.

The hesitation on tip in is random as well unfortunately. At times you step on the gas and away you go. Other times you step on the gas and expect to go but nothing. Maybe a little “cough” from the motor. It’s been bad enough for my wife who knows nothing about cars to comment that something’s wrong my car.

I understand your logic on the MAF and what’s going on with the rise fall rise. Makes sense. Seats! No closer to a fix.

I do have more logs. I’ll pm you…

Thank you again!

 

[horsepower addiction]

different tuning software work a little different. if you had software you could tune the maf sensor. with someone else doing the tuning you just have to hope they made no mistakes. did this problem just pop up or did you just have something done?

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