racecar

Finally got the wideband connected to HPTuners. Before that I would watch the wideband at WOT, it was right on 12.7. Now I'm road racing with the HPTuners data logger and getting some strange numbers at WOT.
PE 1.10 AFR 10.5 O2's 900
PE 1.06 AFR 11.5 O2's 868
PE 1.045 AFR 11.0
PE 1.03 AFR 13.4
PE 1.02 AFR 13.5 O2's 660
PE 1.00 AFR 13.6
This should be linear, does anybody know what is going on here?? Last week, the 1.10PE was 10.5AFR. Yesterday on the track, I was running 1.03PE 13.4AFR, so I changed to 1.06 and blew a 11.5. A small PE change made a huge AFR change. Today I tried the 1.045 thinking I should be right between 11.5 and 13.4, and it ran a 11.0?????
My engine blows some oil due to a ring problem, is my Wideband O2 fouled?
The LTFT's are usually maxed at 25. Any ideas of what is going on here???

JoeyGC5

iTrader: (24)

Oil will make your readings all kind of scewed. The more oil in the exhaust the more it will tend to show a rick condition (at least it seems that way to me anyway).

SUPRYZE

I'm not 100% sure, but my theory is this:

In HP Tuners, you have a table for Open Loop EQ Ratio, which determines the A/F multiplier based on MAP and ECT. When in PE, I think the PCM is going to use the richer of the two tables. If you lean out your PE table, and its leaner than the Open Loop EQ Ratio for your given MAP and Coolant Temp, it will ignore the PE table and use the richer EQ Ratio.

Again, just my hunch (I'm going through the same thing).

Bink

correct^^^^

racecar

Oil on the O2's read rich, that makes sense that they would not read right.
Wow, I have never seen this Open Loop EQ before. Does it override the PE, or do they work together? Most of EQ is 1.13, that would drop 14.7 down to 13.00, then a 1.025PE would give you 12.7 if they both work together, but you guys are thinking that it is using the richest one. Look at the PE numbers that I have tried, it was all making sense until I tried the 1.045 today. Does that look like it is using the EQ table???

RedHardSupra

iTrader: (1)

open loop and pe are often in contest with each other. usually the only area where they're not is cold startup. the moment you WOT it, it goes open loop, and it compares OLFA values vs PE values, and the richer one (higher numerically if you use EQ as units) wins. so if your OLFA is set to 1.13 in WOT regions (usually is on many OS's) and you dictate 1.17 with PE, then PE is gonna win. but if you're trying to lean it out past(less numerically) 1.13 with PE, then the change is never gonna take place, as it's gonna take the richer OLFA number as the final fueling divider.

dont compare wb numbers to nb numbers, nb are completely useless for wot.
if you have to change PE that much, i'm betting that your VE(or MAF depending what you use) is way off. now that you have a wideband hooked up, that can be fixed up in few sessions. also, did you check your injectors and fuel pressure? they can be very easily a cause of radical changes in AFR. last time we talked you mentioned that you have small injectors, you might wanna upgrade that.

www.allmod.net/hpt/VE2IPW.exe is my newest tool to demonstrate how little changes in AFR, air density, injectors not flowing what they're rated at can influence the final pulse width. I'm working on a more flexible version of this tool where you'll be able to ask for different things to calculate, in your case it would be the AFR. This is mostly an educational tool to see relationships between different variable, but it can be used to approximate your fueling needs as well. take a look at it, it needs .net 2.0 to run, so you might wanna install that if you dont have it already.

Johnv

If your LTFT's arn't o 0r - ve when you go into PE mode (WOT) extra fuel from positive fuel trims will be carried through to PE giving inconsistant PE AFR's.
When fuel trims are -ve they go to zerrow at WOT (PE) therfor not affecting PE fueling giving you consistant AFR's.

jimmyblue

iTrader: (11)

Those PE values are all well below the ones in a stock
OLFA (EQ Ratio) table at higher MAP. So you will just
be using the latter (which should make for about a
1.13, 13:1 AFR presuming your airflow and fuel delivery
are modeled straight-up). But with the trims jacked
that far you are nohow straight-up and you'll have a
very variable "contribution" based on the cell you last
were in, before stepping into open loop.

This is why you have to chase the LTFT weasel
around the mulberry bush. You can't tune WOT in a
meaningful way when the basis shifts 0-25% every
launch.

racecar

Right On to everyone. That is a good analysis of what is happening here
OLFR is competing with PE, LTFT's are way high and screwing up both, and oil on the O2's is not helping. Now it makes sense.
The solution is to tune the VE table so that the LTFT's hit zero?? or is there a way to bypass them. Every time I try a SD tune, my car runs crap
BTW, at 6500rpm my injector duty cycle is at 80% so they must be right on, and fuel pressure is 58psi, I'm thinking that that is all good.
Thanks guys.

racecar

I logged over an hour on the race track this weekend. The LTFT's look pretty good at part throttal. It's just at decel and WOT they go to 25. What's up with that??
Has anyone tried to adjust the LTFT min learn time or anything like that to keep them from overreacting. It looks like they just are not geting much signal on decel, and then the max at WOT. Any ideas??

RedHardSupra

iTrader: (1)

if you have a WB, the only reason to look at LTFT's is for a double verification of stoich at non-WOT areas. post your logs and tune, we'll look at them

racecar

How do I upload, when they are ziped, the hpl and hpt are still 390KB and 400KB, I get a message that the max file size is 100??

RedHardSupra

iTrader: (1)

you can just post them on some website and link them. or you can just email them to me