What are your current fuel trims?

 

Well I have read though all the injector scaling and latecy threads but am having issues getting my used PTE880's dialed in at idle.

I started with scaling them at 770 and used the latecy table as a starting point.

my STFT ranged from 7-16%

I changed the table (14v to .871) which gave me a range of -9 to 7 for STFT

Then I changed 14v to .840 and I got a range of -3 to 6 for STFT

I decided to change my scaling to 790 leave 14v at .840 and change 11.7v to .960 and it gave me a range of -2 to 3.

This seems reasonable to everyones standard of +/-4 for STFT idle. My Fuel trim low has never left 0. I left the car idling for 15min but it never budged any ideas on that? Should I leave my STFT idle's alone and move on to cruise?

Thanks,
Aaron

Holy **** just found the supermerge for this. ::Reading::

 

Hey All,

We found an interesting problem with other day.

ID1000's

scaling ~650ish, latencies = cant remember, idle+cruise+stft trims = good!

However the car just ran crappy! and under WOT we couldn't make the fuel table lean enough ...

eventually we fixed the scaling/latencies...

but this poses an interesting question, will more than 1 set of scaling+latencies give good trims?

we now running 812 scaling + doublish the latencies as before and everything is sweet..

car = 2008 MR + ID1000s + FPGreen + TBE (stock intake, stock everything else)

any ideas?

 

Hey tephra,

I think the key is how the car is driven when trying to assess the fuel trims. I've found that many people think its fine to let the car idle continuously for 20+ minutes to assess the idle trim. I've found that gives trims that are not representative of daily driving. Was it anything like that for you?

 

Tephra, yeah more than one set of scaling and latencies can show good trims.

The way to tell if your scaling is good is to compare AFR at WOT after the injector swap, where the latencies have little effect.

 

yeah well thats how we found there was a problem - the AFR@WOT was horribly rich, even for a pretty lean map...

mrfred - umm I dont think we let it idle for that long, just long enough for the LTFT to stabilise - not for fans and things to kick on...

 

I will agree, different scaling and latencies can reach the same desired result, however scaling will determine how the fuel map will look, and latencies are used to dial in the fuel trims afterward.

 

Well the inital scaling+latency we settled on made the car hard to start/bad idle etc

even thou the trim was fine..

 

On my ID1000s, my scaling is at 835... Depends on the car really, as most will use 812...

 

Yes we used 812, but as I said we had to down to 600 at one stage (with latencies adjusted for trims to be close to 0)

 

Hey guys, can you please let me know if there is a solution to this issue? I am experiencing cruise "surging", AFR swinging and car stumbling (~3000rpm) after FIC Bluemax 1450cc injectors were installed.
My ltft low -2, mid -3, but stft 3 to 8%. Also 3 upper Maf scaling values are 250 - these stabilized the idle. Someone mentioned knock multiplier table adjustment? Is that the problem? If yes, what adjustment needed to be done?
Ive done some searching but couldnt come up with anything.
Thanks

 

This is very helpful

 

I am using these values:

Scaling: 812

latencies
4.69v = 5.328
7.03v = 3.144
9.38v = 1.992
11.72v = 1.368
14.06v = 1.008
16.41v = .792
18.68v = .624

But I have the same problem, car is not lean enough at WOT, what latencies did you end up with?

 

well that scaling is about right.

so as long as your trims are about right then you know the latencies are about right..

what other mods u got? maybe the intake needs to be scaled in?

 

I dont need to see the whole map but what values do you have in past 5k for instance? If this isnt SD, has your MAF scaling been adjusted? Made sure there are no boost leaks?

aaron