LvR

I agree with you - a "skewed" MAF sensor can easily be corrected for by having the O2 sensor sit there watching over proceedings - one reason I would have liked to have the animal on our cars here.

ITO the question with the oil/dirt on the sensor and response times being influenced - there is no O2 sensor that can compensate for mis-measured transient air flows - ie - something like a fast throttle position change ...................... by the time the O2 sensor sees something wrong with the combustion product and can react to it, the actual transient may already have passed and the operator already had a cadenza because of ****ty throttle response.

I am totally with you wrt my ECU simply permanently operating in non-closed loop mode because of lack of O2. That said though, at 300000km on the original motor with proper maintenance, it still returns way above avg fuel consumption and performance figures quoted in threads on this board - where as far as I can see all are running with O2s

LvR

I simply love this guy's whole site and the way he approaches and documents experiments.

ITO improved airflow in the intake, restriction, pressure drop etc etc you may find this 5 part article very informative

CapedCadaver

iTrader: (8)

that may be in part to people not having good 02 sensors, or the way they drive, etc. One boosted member has reported tank returns of 31mpg when he chose not to gun it all the time.

1992maximase30

okay first off i know how the maf works i know of two types and i know the 3rd gens.
i did'nt really wanna make a long *** post about how the maf works.
and yea the adjusting i reread his post so i take that back too.
sorry for sounding like an idoit!

i say extend the pipin and leave the maf where it is and it should work...

LvR

That basically vindicates the South African version of the ECU to not run with an O2 I guess.............. and that post changed exactly what? ............... IMO you still don't know the first thing about the MAF's operation or you would never have suggested what you did - long *** post or not.

CapedCadaver

iTrader: (8)

so you know how some have said that the 02 sensored maximas will snap rich once you hit WOT and it opens the loop? have you heard that before?

LvR

Heard that and its probably true since WOT is mostly a transient condition where the O2 would be useless to react timorously anyway and would just confuse the whole fuel quantity delivery system. Most all injected vehicles I have seen, operates in open-loop mode (wrt O2 sensor) during WOT so the Max's ECU is nothing special there

Wiking

FSM states that O2 is not used at WOT, results via TPS-ECU control.

LvR

I knew I read it somewhere but couldn't find it with a quick FSM search .

I do wonder about that unused WOT switch on the TPS though - is the ECU perhaps running open loop way before WOT already?

CapedCadaver

iTrader: (8)

the WOT switch is for the power valve

Wiking

If only there was a FSM with txt [search]

FSM states that neither TPS switch is used - except on TCU/TPS diagnostic phase. Its easy to verify, just plug out...

Also the TPS internal configuration has to be universal for other vehicles, other ctrl sysems.

My guess is that open loop starts 'at 3000rpm'.

LvR

Not according to this on EC12


The power valve is driven from the ECU directly and I very much doubt that the power valve only operates at WOT since the functionality of the power valve is governed by engine load and throttle position as well as engine speed - see EC24

ustfdes

iTrader: (5)

my previous VE maxima, if i pulled the air box, and let the air enter at the MAF sensor, it wouldrun like a beast.....but with my old 240sx, if i tried the same, the MAF got too much air and it would stall and sputter and have crap for power.

but the IACV, imho, should only really affect you at idle, or during cold engine conditions....but im not 100% on that.