accell enrichement problems

[Bimmerjim®]

im using 2.25b541 MT. MSII and EDIS6

last night was the first time since the msII install that the car was crusing at a fixed speed for an extened period of time. i made a trip from lincoln to omaha. (about 1 hr) and after about 10 min of crusing i discovered a few things.

i noticed the car was bucking anytime it was crusing above 2300 rpm (5th gear 75 mph) a datalog revealed the tps accell was turning on at random. i have the o2 corection turned off, but air fuel was staying around 14.0. when the tps accell light would come on it would spike 12.5, then pop back to 15.0, then back to 14.0ish.

so, i started playing with the acceleration wizard.. mixing MAP and TPS made the problem slightly worse, if i moved the bar to only TPS acell then TPS accell light wouldnt come on, but it would still buck only slightly less. i increaced the tps dot threshold to 200v/sec and it didnt change anything. i also changed the map dot threshold to 300 with the same result.

i also cleared both tables to 0 and it would still do it.

im going to go back to MS1. the MSII just hasnt been worth it. iv been fighting it ever since i installed it. i dont have the features in the code that i want, and it just seems to be to flakey.

[Bimmerjim®]

well i converted back to the MS1 and all the issues i had are now gone. the car runs better already. still sorting out the ignition timing again after switching firmware versions and having different settings to mess with, but now i have all the options of the extra code

[78Spit1500Fed]

...a datalog revealed the tps accell was turning on at random. i have the o2 corection turned off, but air fuel was staying around 14.0. when the tps accell light would come on it would spike 12.5, then pop back to 15.0, then back to 14.0ish...

Why don't you post that datalog (and your MSQ) so the developers can help? There's probably an answer, it might not be obvious...

-Brian

[Bruce Bowling]

im going to go back to MS1. the MSII just hasnt been worth it. iv been fighting it ever since i installed it. i dont have the features in the code that i want, and it just seems to be to flakey.

For the TPS accel enrichment kicking in, somehow noise/signal is exceeding the threshold and generating an enrichment, this is what will cause this effect.

You indicate that the old MS/MSSnS does not exhibit this, but you see this on MS-II. I have noticed that I also had to increase the threshold on MS-II compared to original MS. I attribute this to the inrease in resolution of MS-II's ADC and the fact that the ADC acquisition simply runs faster, so there may be a need to increase the averaging or maybe look at another averaging technique or combination. This may be a case where having a processor running too fast is causing issues.

Thank you for testing the MS-II in your vehicle - even though you are having issues, the operational feedback is invaluable so that we can enhance the code. There are not a lot of MS-IIs running out there right now so you are very much a test bed for testing functionality, and if the ADC averaging is not sufficient (as it may be in your installation) then it needs to be corrected. These "growing pains" that MS-II are experiencing are not unlike those that th original MS went thru. I remember a period of about 9 months when the original MS was released where there major issues - burnt-up flyback components, tach trigger problems, resets, etc. It took a while to recitify these to a point where things became stable. MS-II needs to also go thru this growth period, and we have a bunch more code and options to test and work out.

- Bruce

[Kevin Wood]

> You indicate that the old MS/MSSnS does not exhibit this, but you see this
> on MS-II. I have noticed that I also had to increase the threshold on MS-II
> compared to original MS. I attribute this to the inrease in resolution of
> MS-II's ADC and the fact that the ADC acquisition simply runs faster, so
> there may be a need to increase the averaging or maybe look at another
> averaging technique or combination. This may be a case where having a
> processor running too fast is causing issues.

I've noticed worse noise issues with the MS2 on the battery voltage,
temperature and MAP signals with the MSII compared to MSI. My car still runs
great on the MSII but I can't help wondering if the ADC signals could be
improved. As I see it there are 2 possibilities:

1) There is no averaging on most of the signals in the MSII code (MAP
excepted) whereas the MSI code averages over 2 samples on every channel.

2) Could the ADC in the MSII CPU be more sensitive to noise? Maybe the
conversion technique used gets really upset when there is noise on the
inputs. Maybe there's no sample and hold in front of the ADC whereas there
was with the older processor (I 'm speculating here. Looking at the data
sheets is my next step)

1 can be cured by averaging in software. 2 requires more filtering of the
signals in hardware. Either way it's probably something that needs
investigating.

The problem on my car seems to be more one of the occasional rogue value
that's way off rather than just wider variation of values around the mean.
This makes me tend towards thinking that it's noise on the input or power
supply that sometimes throws out a conversion totally.


Kevin



Posted by email.

[Bimmerjim®]

unfortunately my labtop is a cluncky old 486 pent 166 made in the mid 90's. and i dont have any way to transfer data from the labtop to my home pc.

i put the board on the stim on my home pc using the same 2.25b541 and it wont do the tps acell thing that it did while in the car.. so maybe it is noise? the datalog shows that i was holding steady throttle of 15% or more when this would occur.

my main reason for going back to ms1 is because i like to think of my BMW as a race car, and the MSII simply dosent have the functions writen into the code that the MS1 does.

[kalvinlk]

I do not have any experience with ms1, only ms2, but in my install I notice noise in the TPS signal as well. At least I can only call what I am seeing "noise", which is the tps signal flickering between 0/1% and even 0/-1% at an extremely rapid pace. I was reading an excellent article on the innovate website on proper grounding techniques which covered sensors and where they should/shouldn't be grounded, and how with two wire sensors it is necessary to twist the signal and ground wires together and tape/secure them, as the ground acts as a shield. I plan on doing these sorts of things when I complete the install (maybe I will hold out until I get a relay board, I REALLY need some terminal blocks like the relay board provides).

Here's the link if you are interested:
http://www.innovatemotorsports.com/reso ... unding.php

[TimMoman]

Bruce
I also increased noise on the TPS when I switched to MSII. I actually had it somewhat tuned with this TPS flutter. Was not paying attention to my Accel Only noticed when it started surging as I leaned it down for cruise. My setup uses telecom T1 cable which is shielded twisted pair that perform farely well to resist the noise. The coolant also sees noise, After driving around with MT running, I will see the high mark where the coolant has maxed on the gauge. And I am certain the engine has maintained temp. Also using the same telecom cable on all my sensors.

bimmerjim
I believe the early version 1.0 has issues with the TPS/Accel enrichment. Are you running 1.31?

[Bruce Bowling]

OK, there appears to be a common theme with TPS noise on MS-II. Good feedback, I'll put Al to work on this right after he finishes up the issue with the IAC stepper code not operating. Sensor averaging is a pretty easy thing to add to the code - if anyone wants to take a stab at it go ahead (download Codewarrior or use GCC), or wait 'till Al gets it in the code.

- Bruce

[Jim Blackwood]

I've noticed the noise thing too. It's not really caused me any problems so far though. I raised the MAP dot threshold to 300 and run full TPS accel and it seems to work OK that way, though I'm still fine tuning the accel and some other things. There seems to be a lot of noise on the battery voltage line too, probably more than anywhere else.

The truck is really starting to run good. Today I crossed the threshold between having to drive it to tune it and driving it because it was fun. That's a biggie.