I couldn't agree with your more.

 

OK this is what I have tried, first I hooked up a smoke machine to the car, did not find any leaks, so unmetered air is not an issue. Second I richened up my open loop AFR's by 10% (went from 14.7 to 13.2) I did this because of the fuel trims being +10%.I figured this would ball park it for me. Drove around for a while, fuel trims didnt really move ( went down 2% across the board) Next step, I rescaled the injectors down 10% ( from 513 to 472) Bingo bango, nailed the trims to -1 at idle and 0 at cruise. Just now I set my min coolant temp for closed loop to 200 degrees and what do you know, AFR at idle is in the 12's. Now since my trims were in fact at 0. How the hell could these be ? It should be 14.7 or so. Now Im really confused. 14.7 in my 3ff5 map that I created.....14.7 in my open loop map and cruise trims at 0.............but yet if I take the 02 sensor out of the mix 12.8 or so at idle. Anyone have any ideas. Im happy with the 0 and 0 at cruise and idle. Im now just trying to do a little learning about the ECU which obviously takes into account some other variables Im not thinking about.
I have also been checking my O2 feedback to make sure when I run open loop its not going into some sort of safe mode like it did when I unplugged my O2 sensor ( O2 feed went to +25% ) and it was reading 0 so that is out. Any comments are welcome.

Niko

 

Actually, I don't know if this was ever mentioned in this thread, but do you have the breather hose connected to the intake pipe? I mean the hose that goes from the valve cover to the intake pipe after the MAS. If not, or if you have just a breathe filter, this will effect your idle and cruise fuel trims, making them positive.



This sounds right, assuming that you were cruising around in closed loop. The open loop maps shouldn't affect closed-loop. (That's what Jack and I had our OT rant about. This is still up in the air.)

Makes perfect sense again. The injector rescale will affect both closed and open-loop fueling.

Makes sense again. Changing the closed-loop switchover to 200F caused you to idle/cruise in open-loop, so now your changes to the injector scaling affects your idle/cruise AFR.

I think what you don't understand is that the 14.7 you see in the fuel maps are not AFR values. The 14.7 appears to be an AFR value because on a completely stock setup, the 14.7 will match. But, when you adjusted your injectors to be 10% smaller, it made your IPW 10% larger. And that 14.7 isn't 14.7 anymore. It's just a certain amount of time for the injector to stay open. So, now you will get 10% more fuel while in open loop, which you were, since your changed the closed loop to start at 200F coolant temp.

That's why I always tell people if you scale your injectors, you must readjust your open-loop maps by the same amount as you rescaled your injector. So, in your case, if you are going to keep your injectors 10% smaller, then you have to take out 10% fuel in your open-loop maps.


Hopefully, I explained this well enough. Sometimes I gloss over things and don't use the right explanations.


Eric

 

eric that makes perfect sense to me, My breather hose is in fact hooked up. I am now back to 513 for scale and tried open loop 12.5's, Reset the battery and bam right back up to 8-9%.( im guessing 8.5 is the number cause it jumps.) So in my particular case these open loop maps do not seem to help or hurt my closed loop trims. Im actually sitting in the car right now. Dedicated todays "work" day to tunning driveability...man I love being self employed, and to Eric and Jack..........yup corporate sucks. Self employment can rattle your nerves and make you get an ulser and hate people in general, but at the end of the day, its better than working for a living.

 

Ya know.. All that matters is at the end of the day, we all learn something..

And I HATE corporate life.. Right now my job is a piece of cake, unfortunately its also unmotivating, boring, but I have an incredibly flexible work environment, the problem with corporate politics is its alot like being in a union, they compartmentalize your responsibilities to the point that you can't get anything done.. I'd much rather be working freelance again though.

 

And FWIW, I hope Eric is right about the closed loop starting point, working with those MAF tables is alot easier to deal with.. Its obvious that those tables are used, but I think its a combination of the two at this point.. Its unusual that my results have been more indicative of the background map, but I do also have more control over how the MAF operates.

 

Oh and I think it might be easier to tune open loop by setting the min coolant temp for closed loop higher than the operating temp of the car, than it is to disconnect the O2 sensor since it won't trigger any failsafes.. BUT someone has to try this since I havent yet..

 

Right, that's what EvoVette did.


Eric

 

Oh yeah, brain fart.. I misread the post..

 

Hmmm.. been there done that. I am in between jobs at the moment, working freelance is very tempting because like you I also want to try to figure out how to transition away from the corporate world.

reading about the entry points for open and closed loop is interesting. After looking at my own trim levels, it's just another task to do before attempting some more tuning.

This thread got me thinking about properly documented testing procedures. In the FSM they have specific procedures for checking the fuel trims (ironically these are also in in 13A-11 and 13A-12 )

 

Well I had a chance to drive around in low throttle ( closed loop mostly ) and I let the car idle some more. Rock solid trims that hover around 0. Now we can guess as to why this is 1) This is the way to fix fuel trims or 2) I managed to overcome a mechanical issue ( an unmetered intake leak). However wouldnt I still be chasing my trims if I had a leak? or would the fact that I am adding 10% fuel overcome it and stabilize it. Also Jack you mentioned that stock hz at idle are around 32.............I get 40-42 hz if I disable my min HZ value in ECUPlus. Basically all my tests have led to more questions then answers for me. But i have to tell you, this is actually very fun for me. Everytime I figure something out I feel like a todler getting off the training potty for the first time, VICTORIOUS!

 

The fact that you added 10% would stabilize it.

That lends me to believe that you air metering could be slightly off, which may have contributed to the problem with your trims in the first place. Do you have an aftermarket air filter or intake? If so, that can very well be it.



Eric

 

HKS RS intake, could be the culprit. Also since my trims seem to be off at idle and lower RPM's it may very well be a leak. I have noticed that at idle and low RPM ( below 3000 RPM ) my fuel trims tend to stay at 0 , however on the highway if I stay at 3500 RPM for a while the trims tend to float negative (-2 or so). My logic says this, the leak represents a higher % of airflow at lower RPM's thus needing 10% more fuel im my situation. at higher RPM's its less of the total airflow and would account for the negative fuel trims as I go higher up the RPM band. Of course my HKS RS intake could be throwing off the MAF curve all over the powerband thus causing this issue as well. If I only did this much logging when the car was stock I would be able to tell. I could have easily checked the MAF curves and then I would know for sure.
OT: I think I figured out why some people load up the maps with a sea of 8's......this MAF curve makes you bounce all over the place in the load sites.makes smooth timming a pain in the a$$. I think this weekend I may play with the "fuel" setting in ECUPlus to see if I can smooth out the MAF signal, which will smooth out the referenced loads in order to smooth out my timming and fuel............if you followed that line of thought I will be impressed.

 

Some new news.changed some of the targets in the "closed loop target maps" to 14.3. Fuel trims moved in sync. I got them to float back up to +3 % both at idle and cruise. I data logged the AFR's and when I average them out it comes to 14.5 AFR at idle. Havent had a chance to compare the average AFR from a previous log ( one where I didnt touch the 3ff5 map) But Ill report back on monday morning. Sunday is WOT tunning day, the way god intended!

 

Ok I did some more "tunning". I forced the car into open loop by setting my min temp for closed loop to 200 to force the car into constant open loop. I have been slowly creeping up to 14.7 AFR's. More importantly I have been trying to smooth out my transitions. I find it interesting that the P0300 code has followed me into open loop. Im trying to get the car to smoothly transition from 14.7 AFR to 11.5 AFR from cruise to full throttle. Another interesting little info, at 13.7 AFR's my idle sounds and feels perfect, no odd "misses" at idle like I get at 14.7.