Idling problems

[Amien]

Hi Guys the only way I can get my vehicle to idle @ 14.7 is to set the target AFR ratio low.12.8
Vehicle drives fine at 3000rpm in 4th gear= 14.7ish
Injector latency 770
Injector multipier 23300

SR20det S14 1996
Stock turbo
Q45 airflow
740 Deatswerk injectors
What is still wrong

[Fordy]

shouldnt latency be 580us for the injectors as they are just rebored stock injectors?

also i found great success after rescaling my maf translation to my cars intake setup
i found my sr like to idle smoothly at 14.5

[PL]

I've also heard that problems at low load/idle can be fixed by adjusted the VQ map. I've not tried this but I'm gonna give it a go next time I have a problem car...

PL

[all shal perrish]

also i found great success after rescaling my maf translation to my cars intake setup
i found my sr like to idle smoothly at 14.5

maybe you could go further in depth on this?
do you just play around with were it is accessing at idle or what?

please write how you went about doing it

thanks

[Legionnaire]

A wild guess - isn't big bore 4.5l V8 AFM a bit too big for 2l engine? I mean, to idle smoothly VH45 consumes air 2.25 times more than your motor hence AFM curve optimization for that. possibly VQ map adjustments can help?

[Fordy]

a q45 afm will loose your low down resolution but you should at least be able to get it to idle correctly

start again completely
i think your k constant should be 27398
and latency should be 580 unless there is data showing there is a different lag time compared to stock injectors.
set ttpmax to 255 all across
and ttpmin to 0 all across or i found 2 kept it steady

then basically make your map completely flat in target afr's
14.7 to the middle then 12 afr to the end.
now open the maf translation map and with the car running you will which cell its in highlighted in green

you want to highlight the green cell and the 2 to the left of it
then you need to press -, it may take a while but it should bring your afr's to 14.7 as commanded in the fuel map

i've found while on the road you need to highlight the cell in green and the 2 to the left to keep it all smooth

now adjust a few low sections of the map translation parked up from idle to 3000 ish till you get the commanded target afr in the fuel map

now the hard bit where its alot quicker with 2 people one driving and one adjusting

before you go driving make sure you map is safe by taking out a few degrees across the whole map.

then simply drive the car at various speeds and throttle positions and adjust the maf translation map till your getting the target afr in the fuel map on your wideband.

when you start getting to bigger numbers we went down or up in 500s etc

before you do this tho make sure all your boost pipes are tight and exhaust isnt leaking

when you get this sorted you will be able to command a target afr on the fuel map and get it on the wideband this makes things hell of alot easier

also the car will drive alot smoother as the map isnt rough anymore
here's an example of map fuel map now its been fixed

[louiswun]

Hi Fordy,

Please see the chart I have attached, I'm tuning a S14 using Z32 AFM with unknown 555cc injectors (purple side feed, looks like a stock injectors but flow more) on S14 SR20DET, the behavior of the injector is weird.
I cannot get a flat or close to flat A/F line.
I'm using a map like yours, all 14.7 on the low load area.
Stock O2 sensor is un-pluged.
O2 feedback disabled.

The blue line is 1100 injector lantence and 184 at Volt lantance change.
The purple line is 1300 injector lantence and 184 at Volt lantance change.
The yellow line is 1300 injector lantence and 255 at Volt lantance change.
(I have also tried 0 in Volt lantance change, A/F read out is the same as 255)
Any lantence value under 900 will lean to almost stall.
The A/F is checking while engine with no load. rev up slowly.
Do you think if changing the maf translation map will fix this problem ?