You're right....I didn't even notice this was an old thread. I was just replying to new posts.

You Maf scaling solution should work fine. Or, if you want, you can even try to use your open loop fueling map for the loads/RPM that you are at when you cold start.


Eric

 

Funny thing is, I think my car has been doing this for some time as well. Since I just got my datalogging stuff, I havent played with it much yet, but I do know what I feel when driving. on cool mornings(it been 50's here last couple of days) the car has a very bad tip-in hesitation on accel until the temp needle starts moving. once the car has warmed just a little, car drives fine. Looking at my high octane map, the bottom numbers are all in the 14.7 range, except the very corner is at like 15.x. Would richening these numbers up help any?

 

Yeah, that would be the easy way to do it I just have an aversions to doing that cause I have seen soooo many maps where injectors were scaled via the fuel maps that it just nags at me to do it that way.

Eventually I will get it sorted I just keep changing stuff so often that I figure I may as well wait till I'm done modding... but they like most of us.. that will probably never happen.

 

I very well could, but you have to watch the fuel trims and see where they are at idle with the car warmed up good. If they are more than +5 or so you should probably adjust the injector latency and or scale to get them as close to zero as you can.

Are you running an after market intake or upgraded injectors?

 

If you don't mind sharing, what's the update on this? Have you changed the maf scaling table or did you change the afr map? And if you used maf table, what values did you end up with ? I assume 19 to 75-100 values need to be changed for idle...

 

Bump here...

I got the same problem as well now that i installed my 1000cc injectors.\
When i first start it, it runs in the region of 17-18 AFR on wideband and the settles down, must be as the ECU is catching up and doing the fuel trim.

I have Apexi intake with 1000cc injectors, MAF has not been scaled...
My STFT and LTFT were at 2 and 4. so i think they OK!

how can we fix this ???

 

My logs indicate that only the values below 50 hz affect idle. Idle w/o AC on is around 28-30 hz and idle w/ AC is a little over 45 hz.

 

Yeah i changed the values a while back in my 19 - 100 range. I know it idles at round 37-45, but i changed them all to make the transition smooth, otherwise if you increase only 50 value, the car will stumble once it passes 50hz if the value is higher then the next one.

So after bumping the values, my cold start on 1000 injectors and E85 and a cone filter is spot on -- 14.7-14.9. From 16-17 that i had before.

 

It settles down because O2 warms up and starts working and puts you into closed loop. Until that you idle in open loop, so you need to adjust your MAF scaling. So rescale your MAF and put these values in.
19 160
25 175
50 180
75 181

Basically it takes 10 or so minutes of changing values little by little and reflashing until you get the idle right. Make sure to do it with cold O2 (you'll know it's cold and inactive if you log it, it will show 0 (o2 feedback))

 

Thanks a stack bud i will give it a try and see.
when it warms up and the O2 catches up it settles down!

and these figure are in the MAF scaling table right?

should i change it in the MAF smoothing Table
my values are
192 114
256 114
512 116
768 119
1024 119 etc

 

Don't worry about the smoothing table. Change values in the MAF scaling table. Before you do though you will need to rescale your MAF scaling table, so you can use the values i referenced. (pretty easy and quick https://www.evolutionm.net/forums/sh...d.php?t=249388)

 

What if your warm idle is lean, would adding latency help?

I have added alot of latency but my fuel trim is -2 mid and +5 for idle. How can I lower my idle trim more?

Also, if adding more latency, how does this affect my fuel map?

 

If you don't have your breather hose connected (the one that goes from your valve cover to your intake pipe after the MAF), then that is your problem.


Eric

 

Unless you have changed injectors i would leave the latencies alone.
If you changed your intake then i'd look into MAF settings.

 

Bigger injectors. Strangely, when I fitted bigger intercooler my idle went very lean. Since, I have increased latency by x7 and now it idles alot smoother but my trim is at +5. Do I keep adding latency?

Also my hoses are all connected.

??? Any ideas?