AlwaysinBoost

iTrader: (17)

I'm in the process of re-adjusting my injector scaling/latency values using the info found on the forums and I think I hit a wall.

I'm running RC1000's and used some scaling/latency figures found in the huge INJ scaling thread

scaling = 860
3.312
2.184
1.560
.936
.624
.384
.288

Inputting those values and logging trims for a 20+ minute cruise gave me LTFT values of -6.x mid and -7.x low.

So I upped my inj. scaling from 860 to 886 and did another 20+ minute cruise and as a result my LTFT mid went from -6.x to -.6x (perfect).

Next it was time to work on my LTFT Low (idle). So I started the car and sat for 20+ minutes while I watched the idle trim drop to -12.449x (maxed out) and stay there. Mean while the STFT (o2 feedback) was pegged @ -25 (also maxed out). I figured next I would adjust the latency values DOWN to reduce the amount of fuel being added @ idle.

In four different flashes I went from a value of .624 @ 14v all the way down to .552 without the LTFT Low trims moving at all. How can this be? I know for sure my LTFT Mid tirms were effected, because on my drive home my cruise trims went positive from their initial value of -.6, but the LTFT Low values stayed the same.

One thing to mention is that I didn't pull the NEG battery cable to reset the trims after each flash, but I didn't think that mattered if you were allowing the car to run for 20+ minutes to cycle the trims. I also didn't pull the NEG bat cable when I did the cruise trims and that worked.

So I'm kinda stumped here. I'm thinking about just making my idle be in open loop and adjust it that way, but I kinda feel like that is cheating/giving up in a way and I want to fix this problem, not put a bandaid on it, lol.

Boosted Tuning

iTrader: (12)

Disconnecting the ground and reseting the trims will help a lot. Especially since the went so far off so fast.

Jack_of_Trades

iTrader: (17)

Its possible that your trims are just so far beyond adjustment that even with the latency change, its still out of range perhaps. Definitely do a reset and see if the problem persists.

AlwaysinBoost

iTrader: (17)

thanks guys, I will try pulling the NEG cable and report back.

l2r99gst

iTrader: (2)

There is no need to sit there and idle for 20 minutes. Just look at your LTFT Lo and STFT and you will know what your LTFT Lo will eventually settle at.

You haven't touched your low end maf scaling by chance, have you?

AlwaysinBoost

iTrader: (17)

after pulling the NEG cable my trims still went to -12.4xxx.

Eric, my stft is -25 and ltft low is -12, so that means I'm -37 or way out of the scaling range on my settings. No, I haven't touched the MAF scaling settings at all.

AlwaysinBoost

iTrader: (17)

suggestions?

l2r99gst

iTrader: (2)

If you know youre scaling is correct, meaning your WOT AFRs are the same before and after the new injectors at your scaling, then your issue could be a leak anywhere from the map to the IM, possibly from the turbo to the throttle body.

Check all IC pipe connections, DV connections, etc. Are you running a breather filter or do you have it routed back to the intake pipe, etc, etc. Check any hoses on the back of the throttle body, too.

If everything checks out OK, a bad O2 sensor could be possible as well. If that checks out, you can try reducing latency a lot. But I don't know those injectors or the true latency values. If others have used the values you are using OK, then I would think one of the isses I mentioned above may be the culprit.

Of course, this is assuming that the scaling is correct as it sits now.

AlwaysinBoost

iTrader: (17)

I don't know if the scaling is correct or not. I just took these values from the huge injector latency/scaling thread and used them as a fresh starting point. These aren't new injectors, I've been running them for a while now (4 years or so). It just that I recently started tuning again after a hiatus and I want to take care of all my driveability issues.

my previous scaling was 813 for injectors and I believe my latency value was .4xx @ 14v.

The difference between where I am now with regard to my AFR on the fuel maps and where i was with 813 scaling is that I'm about a full 1 to 1.5 points leaner on my wideband now compared to my old scalings.

I'm pretty diligent about leaks, I boost leak test often. Right now I no I have only a small one on my JMF FMIC where the core meets the end tanks. I don't use a breather on the valve cover, that line is plumbed back into my intake post MAF.

I don't think my front o2 is bad. it was replaced not too long ago and I don't use leaded race gas. Cruise trims seem fine, its just the idle trims. wouldn't a bad front o2 mess both trims up? is there a way to tell if is def bad?

I have a race coming up tomorrow so I'm just going to load my old scalings back in for now until I can readdress this issue over the weekend.