can anyone give me the value of their MAF sensor value at idle when the car is in operating temperature(warmed up)? I need to compare it with my xjr6's maf reading.
Thank you so much!

 

As I recall, the reported OBD MAF parameter was so far "in the weeds" from a reasonable value even when running right that a consensus developed the assumption that it was scaled wrong. I therefore never felt it was of much use to chart. Unfortunately, I do not have a running 300 to measure for you.

 

Yes, i was shocked at the value comparing it to my mazda, so i was curious to see what the values are from other member.

 

I just filtered my 1.5 hr drive home from the Ballpark in Arlington for Engine RPM<700 and OBD Speed=0:
MAF values were predominately 0.48 and 0.4, with some 0.32 and 3 odd 0.56 points. (cfm) and data taken at 1 second intervals.

 

Yeah, those are the numbers most of us read. BUT...if the engine is producing 10 HP under some very normal conditions, you would need a theoretical 13 scfm or so of air.

REQUIRED AIRFLOW (scfm) = 2.723 x HP x BSFC ( BSFC about .5 or so)

I do not believe that the X-300 engine can turn the engine and auxiliaries at idle generating .3 HP!

Or, do I have some math error?

 

@sparkenzap interesting equation I had no idea about that, u just opened up my mind to something brand new

 

thank you so much aholbro1! the maf reading seem similar on mine so i'm gonna say its good! any chance you can give me the STFU and LTFU value too? at idle?

 

I'm not sure about "STFU"....well...I am, but I suspect you mean something else, and likely related to ECM data, anyway, here's what I *think* you mean:

From left to right, it goes Bank 1 Long Term, Bank 1 Short Term, Bank 2 Long Term, Bank 2 Short Term.

(you can read "Fuel Trim Bank..." in the header of the pdf file, but I don't think the Long/short part is visible)
Everything is at idle - as it is still filtered for rpm and speed

Edit: Oopsies! I just reviewed that pdf and it looks like the last 60-80 pages or so might be after I shut the car off and walked into the house - guess I forgot to secure "Torque" ..sorry, but anything prior to 6:15 pm ought to be good data.

 

i was reading the log, is there a % or something ? all i see is number.

 

Yeah, sorry, all the fuel trims are in % - also listed in the column header and unreadable

 

Thank you so much! that helped me alot!

 

Excellent points all around, Ross. I perceived Frozen was more interested in whether the values he was getting were similar to anyone else's x300; whether they made any sense or not, and needed some for comparison. So there you have it.
I HAVE noted that my X300 MAF values always seem to be several orders of magnitude less than what I get from the S-Types. Inasmuch as I'd just recently obtained a $12 ELM327 Clone that seems to work (my higher-priced ScanTool version freezes up after 30 sec or so on all 3 X300's!....no problems on the S-types, however) I have been logging trips again so I had that handy.

BSFC? B....Specific Fuel Consumption? Help me out.

 

B= brake. Units are lb (of fuel)/ HP hour. It's a measure of how efficient an engine is.

 

Yes, to some extent comparisons are in order, but I doubt you could legitimately condemn or confirm good a MAF with the readings, as long as it seemed to track higher and lower in response to rpm.

The equations are actually only relevant for near WOT throttle. All kinds of things come into play, like how much the air is changing temperature as it is pulled in, how much it relatively heats as compression occurs and on and on, but the point is the X-300 OBD values are orders of magnitude away from realistic.