Engine load

[dcb]

What is on the horizontal axis on the VE chart? What scale?

Also I assume the second picture uses seconds on the horizontal axis.

[mwebb]

for the calculated load PID to be accurate
real time fuel trim MB 33 on VW Audi OR
STFT short term fuel trim OR fuel trim on the front 02 sensor on America or Asian

must be within +/- 5% from zero at WOT , wide open throttle and at idle and 2k rpm

MB 32 on VW Audi or
LTFT long term fuel trim (American / Asian) MUST also be +/- 5% from zero
================
intake vacuum
is
useless for this
- the car above has either Under reporting NEW MAF sensor OR restricted fuel delivery , based on Calculated Load at 80% at WOT with
real time fuel trim adding over 15% at WOT .

test
do
not guess - graph or log the data to play it back

do not attempt this with tinker toy scan tools - they can not do it.
OBD-2 Vehicle Explorer Scan Tool Browser this is the cheapest real scan tool
Escan is better AutoEnginuity is very much better. VCDS is outstanding for VW Audi and
has ISO 9141 2 , OBD2 generic for lesser cars

vacuum
is only a portion of the load calculation , Calculated Load or ENGINE LOAD
is the sum total of all the LOAD PIDS as processed by the ECM in real time .

fuel delivery is determined by
CALCULATED LOAD or ENGINE LOAD .... not intake vacuum

[mwebb]

Originally Posted by dcb

What is on the horizontal axis on the VE chart? What scale?

Also I assume the second picture uses seconds on the horizontal axis.

i would have to log it or save the graph data
which i did not do and usually do not do , i just grab a screen cap after the WOT pass , which lasts from about 20 mph to about 65 mph in as long as it takes the car in question to cover that change in speed at WOT ..... the data a cruise before and decel after is also included .

the AE info was logged , then played back, same thing
i could look up the time in the csv file to see , but it really does not matter , i am looking for peak values at WOT ... most of the time.

[mwebb]

i have an MPGuino on my steering column , it works very well to display real time FE and trip FE along with the other things it does , on an OBD2 car
a Geo Metro. the VW and Audi have real time FE things in the factory instrumentation .

i do NOT use a vacuum gauge excepting when testing engine condition

imho
for most cars for most users
in it's present form
the MPGuino is the best bang for the buck to determine real time and trip fuel economy
even if the car in question is
an OBD2 car

it is a KISS (keep it simple stupid )tool and it is outstanding