fao e36 types. obc/fuel consumption question

Matt82

Matt82

Matt82

Soldato
Joined
13 Mar 2004
Posts
16,649
Hi there

The obc gives a for fuel use in litres/hour in the hidden functions. Mine reads 1.5 to 1.6 idle but I want a few ideas of whats normal.

Anyone?
 
cheers fellas. trying to get my head around the ecu with the aim of getting everything operating as it should.

it is definitely running rich at the moment, things arnt right.

need to get some diagnostic hard/software setup and a way of monitoring the ecu's inputs.

i want new lambdas and MAF but im not sure whether i should forego the MAF and just get an "alpha-n" remap which e36 types harp about a lot
 
from what ive gathered so far they remap the ecu to no longer rely on MAF input, it uses throttle position and engine speed instead. apparently it can net more power

new MAF is at least £200, so im wondering if its worth considering this "alpha-n" job
 
Matt, my 328i used to read 0.9 - 1.0 Ltr/hr

It averaged around 25 mpg - e36 328i auto

Hope this helps? :)
 
that goes a fair way to explaining why it smells at the tail pipes end

need to find out as much as possible about the ecu and how it operates. if i get some scans from autodata, ill post them up
 
from the info i get from the bosch website, those particular lambdas are wideband, but i dont know yet how the ecu uses the info (ie wideband or not)

with 30% off at euros (more than my normal discount) it works out at £300 ish for the set which isnt too bad
 
image.jpg

Litres per hr @ idle - my Scania, 13ltr diesel, its 2 l/hr consumption makes your M3 seem relatively thirsty by comparison!!
 
http://www.megamanual.com/v22manual/mtune.htm

something to read there

seeing as ive not seen any sign of a MAP sensor on my E36 i cant see how it would work

Tuning with Alpha-N

MegaSquirt can be converted from speed-density to use RPM , temperature and TPS only. This is called "Alpha-N". Alpha-N uses the only throttle position and RPM to calculate the amount of fuel to inject as opposed to using the manifold absolute pressure and RPM to calculate the amount of fuel to inject.

With boosted engines, you MUST use the speed density algorithm with MegaSquirt® EFI Controller, because the throttle position bears little relationship to the amount of air going into the engine. Alpha-N is for naturally aspirated engines ONLY.

Using the speed-density algorithm, MAP is the main variable and VE is a 'tweak'. On alpha-N the VE table is the main variable, as TPS is used as a lookup into this table. Actually it is a fuel map rather than a VE table.

Alpha-N is useful for long duration cams where the resolution of manifold air pressure (map) would be small. It is also useful to get smother idle on engines that have erratic map values.

For example: On a flat part of the torque curve, going from half to ¾ throttle might not require the value to change in the VE map on speed-density if the air/fuel ratio is the same for the 2 loads as the change in MAP will do this. On the alpha-N system the map bins will be different as this is the only way the MegaSquirt can find out about the higher fuel demand.

You must have v2.0 or higher of the embedded software installed. Start up the tuning software, go to the Constants dialog and change speed density to Alpha-N. Then you 're-map' your VE table.

In Alpha-N mode MS still makes 02 corrections (i.e runs 'closed loop'), if you have it enabled.

One thing you have to always remember with alpha-N that you don't actually know where the effective WOT is anymore (i.e., when you have enough throttle that opening it further doesn't affect the amount of air being ingested). At low RPM WOT could be only 20% throttle.

As an aside, there has been a change in the way v3.000 alpha-N works, it now multiplies in TPS as a factor, where v2.0 did not multiply by TPS.

In V3.00 embedded code the fuel equation (minus the enrichments and open/close time) looks like:




PW = Req_Fuel * tps * VE(tps,rpm)
Click to expand...
 
Clarkey said:
what mpg you getting? should be about 25 average. I don't think l/h at idle means anything really, you don't drive idling.
Click to expand...

it seems to vary quite a bit but so too has my driving patterns. going to work today OBC said 26mpg+

if its left for quite a while it seems to settle to 23-24mpg, which seems reasonable, but it smells rich at the exhaust and also my bum dyno says the torque is tailing off too early.

so the aim of this stage is to regain the missing power and in turn get it running properly. i suspect it is running rich due to the smell
 
Have you checked and reset/redone the fuel settings on the obc?

It's been a while since I had the 18 Button OBC but to get the most accurate figures you need to ensure that the settings are correct. I don't recall where the settings are or what they should be though...helpful I know. :p
 
3.0 and its a 1994, obd1 with the round connector.

so far i am considering carsoft or inpa. i was to see fault codes and i want to see "live data" from the ecu too as its useful to see if the data is all plausible
 
You must log in or register to reply here.
Back
Top Bottom