Hi there!

I made some strange experiance today for the first time:

After drivening on the highway and then standing in trafic my CEL came up, most probably due to some O2-Sensor-thing with 100-cell cat.
Anyway, as I dont like this I just disconnected the minus pol of the battery and switched on the lights to make sure every electric capacity would be gone, reconnected and started the car.... oh-oh! Unpropper ideling and the car would run much leaner than befor in open loop.
Afer all I had to rescale the injetors from 450 down to 380 to get it right again...

As said, looking back this already happend befor when I had to rescale from 550 to 450 (they are actually 780er running on E85)

I read the file from the ECU and saw nothing special. I tuned the car with OpenECU on E85 with works great.

Does anybody of you know this effect and can anyone explain what might have happend here and how to fix it...

Best regards
Kunz

 

It sounds to me like the injectors weren't scaled properly to begin with and the trims reset when you pulled the power. This could have happened because you were scaling the injectors with the trims in action and it was giving you erroneous results.

For instance ... you could have started with the scaling too high causing the trims to rise. You then changed the injector scaling without resetting the trims so the positive trim was still in place. When you pulled the power, that positive trim offset went away and you are now running lean again.

 

I agree with TouringBubble.

 

Thanks for the replies!
This sounds reasonable to me! I thought about the ECU having some corrections saved that were thrown out now. The only thing that made me doubt was the fact that it happened twice; once at the beginning of wintertime and once now...
So partly removed corrections?

 

Get your scaling and injector latencies tuned better and you won't have that issue.

 

Exactly.

And this is exactly why I hate scaling injectors on a VIII.

 

Also, 780cc might not be enough for E85. Because my scaling values on 1050cc is 585 for E85.

 

So if I all got you right, you would now not wait until the ECU learnd the correction again but would tune the scaling right away so correction done by the ECU is close to zero...


teanaive:
Yes, thas what I thought in the beginning too. But I can easily run ratios down to 10 and lower (fuel rated) but tuned the car to about 11.5, so should have some space left.
But right, as soon as I will start to play around with cams or turbo, I will get to the limit.
By the way, what are your experances concerning spool-up - especially at low revs - with the cams you drive; laggier? more aggressive?

 

I think what this is refering to, is the fact that every time you make a scaling adjustment on the VIII you have to disconnect the battery for a few minutes to reset the trims, correct? On the IX's every time you reflash it, it resets the trims for you. If my understanding is incorrect, someone please correct me as I am learning this also. Thanks

Josh