04SCLariat

i have an 04 5.4 SCrew, gotts mod, aem dry filter, borla exhaust and edge programmer. Does anybody have the specs on what the maf g/s should be reading at idle, acceleration, and wot? Thanks in advance

F150Torqued

Loaded question! Grams per second is a pretty fine measurement - and even sensitive to Idle RPM. I can give you a small table - but at WOT, I usually have something else much more important on my mind. From screenshots of my Torque Pro monitoring screen for live O2 & Fuel Trim data, I know it is not 'exactly linear' - because of BARO(), IAT and Vacuum. You can not just simply multiply the 1850 RPM reading by 3 and determine what it would be at 5550. The OBDII system does some 'calibration' on it and reports it in g/s pretty darned accurately to keep F/A ratio right.


My 2004 5.4L Triton looks like this:
RPMs - g/s
590 - 4.22
610 - 5.04
860 - 9.6
1715 - 33.8 - 70% load
1850 - 23.45 - no load reving




MAF Reading @ 1850 RPM
*NOTE - to avoid confusion: Cats were NOT warmed up and working yet. Had 'just' gone into closed loop. Rear O2 readings would normally be relatively level at around .6 to .7 volts.

04SCLariat

Sorry for the extremely delayed response. My worry now after seeing your figures is the fact I'm at least double that on all of them. I'm reading around 8g/s at idle, around 50 g/s at 50% throttle and well over 110 g/s at WOat. I'm on my second engine which now has 45k on it. At 145k my factory engine rapped out from running too rich. It burned a whole through the piston and literally broke a connecting rod. I don't want anything else to happen as I love my truck plus who can afford to keep replacing engines? Am I just breathing REALLY well? Or is there possibly an underlying issue here?

04SCLariat

Also, my "performance" mods include a gotts mod, borla muffler with 2 1/2" pipe ending before the axle, arm drop in filter, and edge tuner on level 2 "tow/haul mode" I also have a slight "ping" ever since I got the muffler put on at about 50% throttle. Took it to a ford dealer when I had full factory exhaust + just the muffler and the tech said the "air in the exhaust was making the noise due to restriction" I've never in my life heard of such a thing but took his word of removing the dual tip and it never went away. I've shortened my pipe even more and it still does the same. Not sure if that's related or not

F150Torqued

And you have a slight 'ping'???.


Your post left me curious enough to start doubting myself. So I did a little test on my truck today.


As I mentioned previously, Grams/Second is a very fine measurement of air flow. It is difficult to talk about what is "Normal", because almost nothing is 'Normal". _EVERYTHING_ effects it some - often greater than one thinks it should. While it seems on the surface one should be able to calculate what it should be by multiplying RPM by engine displacement, that doesn't work out because of IAT, BARO(), VACUUM (which is a function of load) and probably some other stuff I haven't thought of or don't understand gets involved.


With those above mentioned MODS, all bets are off. One thing for almost certain, the edge tune likely has altered ignition advance. Increased advance increases the engine load at idle. Increased load (even though RPMs decline) increases throttle plate position - effects vacuum - and therefore G/S MAF.)


To verify my thinking, I grabbed two screenshots today. Engine at full operating temperature, 100 degrees outside air temp, Baro() 29.92. First screenshot is idling in neutral with A/C on - showing 650 rpm. The second - everything same except in Drive - idle went to 606 rpm, BUT G/S went up from 6.21 G/S to 7.06.


As for your 'ping', that may have something to do with timing advance via that tune. You might use Torque Pro and monitor your Knock Sensor Volts on both banks.


They are at PID #16E6 and $16E7. Extended PID/Sensor definitions as follows:


Mode/PID : 2216E6
Long Name: Knock Sensor Bank1
Short Nm : KS_1
Min - Max: 0 - 5
Units : Volts
Equation: ((A*256+B)/1024)*5
Header: Auto

Mode/PID : 2216E7
Long Name: Knock Sensor Bank2
Short Nm : KS_2
Min - Max: 0 - 5
Units : Volts
Equation: ((A*256+B)/1024)*5
Header: Auto


Mine bobbles around 1.2 to 1.4 at idle or light cruising. If you get on it, they'll go crazy - and monitoring timing advance by them you will see the PCM jerk timing back when they get over about 4 volts.