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Open loop to closed loop transition - time related? Tephra V7

 
Old Jul 22, 2011, 05:46 PM
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Open loop to closed loop transition - time related? Tephra V7

Hi All,

Ive been doing some reading around the ECU Flash in general but could not find some information regarding the transition from Open loop into closed loop. I was curious is this is time or temperature related? Ultimately, im trying to resolve my economy issue. Ill be getting a cable and ECU flash this week so I can make the adjustments myself, but for the interim, would like to know what you guys think.

Goal: Trying to iron out my higher than average fuel consumption

Symptom:
Once car warms up to desired operating temp, AFR's are in the 12-13's (E85) at idle and cruise causing too much fuel useage

Mod: Mild Cams (Tomei 260), Apexi Pod, FIC 950cc, TBE without cat, Works fuel rail, adjustable FPR set at 42psi rail pressure, single walbro, Tephra V7, E85

Scenario 1: Complete cold start driving
Car starts off desireable and runs for about 15mins until the AFRs start dipping rich. Prior to that, the AFRs are 15-16.. If you turn off the car and turn it back on, you will get another 10-15mins or so before the AFRs start dipping rich again. This is alot of heavy city traffic driving.

Scenario 2: Freeway driving once warm
Car starts off desireable and runs for 15mins and then the AFR will start dipping rich, i.e. 13's

Possible solutions I can think of off the top of my head:

- Induce open loop early

Its hard to say without having a look at the data until I get the cable, but hoping you guys might be able to help or point me in the right direction as it could be tune related.
Attached Files
File Type: hex
BKT87Y_6.hex (256.0 KB, 0 views)

Last edited by Mr_G; Jul 29, 2011 at 02:15 AM.
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Old Jul 22, 2011, 11:22 PM
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yeh its pointless guessing until you get a datalog.
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Old Jul 26, 2011, 02:33 AM
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Halfway there... Got the cable, time to get Evoscan and provide some logging.
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Old Jul 28, 2011, 05:59 AM
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Ok guys. Purchased Evoscan the other night and did 3 logs today. Only short ones as its hard driving peak hour in Sydney to work and trying to log using laptop on passanger seat! Logs are in Post #1

Logs include:

- Cold idle where it starts of pretty lean (Goes over 18 on the AEM)
- Once the car warms up, the idle smoothens out (Sits around 13.5) so have a log of this
- Small cruise around 40km an hour once warm

I have cold start issues where the car feels like it needs more fuel to get going. The car will rev up to 2krpm to begin, but idle will drop down to 1krpm , then back up to 1.5k and setlle on 1k rpm till the car is warmed up. Pre warm up, the car feels like it needs more fuel.

Hopefully some of you can help. I think maybe I need to have my cold maps checked first before I start playing with the cruise?
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Old Jul 28, 2011, 07:16 AM
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Since you didn't have a cable and ECUFlash to begin with, who tuned your car? I see it's modded on E85, so I am assuming someone helped you and tuned it?

I only took a quick look at your cruise log and final idle log. Immediately I noticed that your fuel trims aren't even registering and for your cruise log, the STFT is pegged rich at +25, with your front O2 being pegged lean, near 0.

Also, it looks like your load is off quite a bit. The beginning of that log showed load at 357. Cruise should all be around the 100ish range, depending on how much boost/vacuum, etc. Even in your idle log, your load was mid 60s, which is a bit high.

So, before any kind of help, I think we need to see the ROM to see what has been done. It looks like there may be quite a few tuning issues at this time. My first instinct would be to look at injector scaling, maf scaling, and the open loop tables. But that would be just a start. There's something definitely way off in your tune.
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Old Jul 28, 2011, 10:56 PM
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Hey mate,

Thanks for taking the time to look at my logs. Im not too sure if my load is correct as Im abit of a NOOB. I pretty much downloaded ECU flash, Tephra V7 Xml's and Evo Scan. Plugged up Evoscan and selected a few things to log and so forth.

The car was tuned by someone else, but only for WOT and some cruising around, however i need to iron out the bad lean cold starts, the odd AFR issues it has and to increase fuel economy.

I'll upload my 9653 rom when I get back from work. Any other pointers would be most helpful but will be able to re-scale the injectors over the upcomming weekend. Im assuming you re-scale the MAF after you have got the STFT and LTFT done?

FYI, Ive tried playing with some of the settings to let it run in full open loop

Last edited by Mr_G; Jul 29, 2011 at 02:20 AM.
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Old Jul 29, 2011, 02:16 AM
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Have added my ROM file in post 1

Cheers
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Old Jul 29, 2011, 07:27 AM
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OK, I'll try to take a look later today. My XMLs are way different than what's posted on the forms for this series of ROM, so it will take me a bit to get them setup to read your ROM correctly.

But I'll take a look to see what I can find and go from there. I'm halfway around the world from you, so it will most likely be overnight for you as I'm starting work right now.
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Old Jul 29, 2011, 07:47 AM
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Thanks for this as this fuel and drivability issue has been bugging me! Tomorrow morning, I will revert back to running open and closed loop instead of the full time open loop setting and do some logs to see if the the values differ much to the ones I posted earlier.

Dont work too hard now, after all its almost the weekend for your where as Ive just started mine
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Old Jul 29, 2011, 11:43 AM
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Yeah, that's right, so don't expect too much

More logs will definitely be beneficial. Be sure to log the fuel trims, both long and short, load, Hz, wideband if you can, etc. The more data there is, the easier it will be to tune.

Your main goal, though, should be pretty easily attainable. Turning back on closed loop will tell us how much extra fueling is being taken away and we tune the injectors from there. It's that simple. The rest of the issues can be tackled one at a time. E85 is a different animal, so IPW tables can be used to tune better starting (hot, cold, warm) and MAF decay tables can be used to richen the warmup period if need be.

Last edited by l2r99gst; Jul 29, 2011 at 11:46 AM.
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Old Jul 29, 2011, 12:26 PM
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Load may be off because of the 1byte multiplier in Tephra V7 and EvoScan may not be the same. Just a thought.
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Old Jul 30, 2011, 12:52 AM
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Comments above are a bit of a relief Ive changed a crapload of parts to try and figure out this issue and its driving me nuts! (Fuel pump, injectors, rail, FPR, Water temp sender, TPS, AFM)

Im currently in the process of setting up the AEM to log through Evoscan so ive installed the appropriate cables and just trying to ensure it logs on evoscan.

In the interim, did 3 logs today going back to normal open and closed loop setting, no forcing the car to stay in open loop. 1 warm idle, 1 start up idle about 1hr after driving the car where it goes lean and one drive of around 80km/h for a few mins.

Thanks heaps for the help, more than appreciate!

FYI, The car seemed to target the 14.7 mark alot better on idle once warm today. It really didnt defer much away from that which was something different. Mind you, today has been a little warmer than the last few days.

Attached are the logs and current Rom hex im using today
Attached Files
File Type: hex
BKT87Y_4.hex (256.0 KB, 0 views)
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Old Jul 30, 2011, 10:39 AM
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OK, won't have a lot of time until the start of the week to help, but a couple comments confused me.

You said you are setting up the AEM, yet you are posting ECUFlash Roms. Which is it?

Anyway, took a quick look. Either your fueling is way lean or your o2 feedback and fuel trims are simply not working. At cruise and warm idle, all trims are 0 with STFT pegged rich at +25%.

But that goes against what your main goal stated. You said that your car is running rich during cruise and after warmup, correct? That doesn't make sense with the log that was posted. The log (if correct) is showing the ECU adding 25% fuel trying to get to stoich, because it is too lean. The front O2 sesnor is reporting near 0 (lean).

So, if your car really is running rich and your wideband is accurate, then your front o2 sensor is dead and needs to be replaced, or possibly disabled somehwere in the ROM (but I think you wouldn't get any reading that way, not sure). If your front o2 sensor is working, then your AFR readings make no sense. Based on the logs, your car should be running very lean or at least stoich. The logs would suggest you need to change your injector scaling down by a good 20% or so.

I'll take a better look after the weekend, but if you can answer those couple questions or provide some clarification, it would help out.

Last edited by l2r99gst; Jul 30, 2011 at 10:45 AM.
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Old Jul 30, 2011, 05:59 PM
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Hiya,

Definitely running ECU flash. The AEM comment was in relation to the wideband which I have managed to setup now to start logging by putting the cable together and turning on the settings in Evoscan.

With regards to the goal im trying to achieve, im trying to get my mileage back to where it use to be and also have iron out a better cold start.I was told by some friends who help do the initial tune that they would load the tune, and we would go cruising on the freeway to test. Then randomly the car would start throwing fuel out of no where causing excessive fuel consumption for no reason. They said it would start out fine but then all of a sudden it starts throwing around 20% more.

If the 02 sensor was running properly, what should the reading be in the log under the'O2 sensor' column on idle? Im assuming around 14.7? Is there other ways I can test to see if the 02 is working properly?

Now that I have the wideband setup for logging, I will try and get some more logs done today for warm idle, pure cold start and a cruise
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Old Jul 30, 2011, 07:36 PM
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You're running 713 scaling on 1000cc injectors on E85?
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