Members Page/Jim W - VEMS wiki www.vems.hu

MembersPage/JimW (2006-03-16 04:43:08)

Switching to Genboard on my Golf racer before next season, because K-Jet isn't cutting it. Later on I will be doing forced induction, so I need room for change.

Pictures and some info:

http://proton.shadowflux.com/vwracing/

email james at shadowflux dot com

I have edited a config file and would like to submit it for review. I hope it will be an improvement on the one everyone has been using.

the uptodate config is found {{```[http://proton.shadowflux.com/vems/test_config.txt]```} http://proton.shadowflux.com/vems/test_config.txt

Notes about subsystems (to verify/justify config variables) on pages below

MembersPage/JimW/config

My installation to date:

Testing, experimenting, and learning with Genboard/PC.

Starting a new job, so time and money have been in short supply. More parts and testing are necessary before installation is complete.

When uploading the firmware via avrprog: Click 'Exit' after finished uploading, window greyed and only available action is to click X to close (no matter how much time passes). Was worried that the upper bits would not be written to flash, but everything seems okay. Update (3/18): Have repeated this several times and everything works out okay.

I am trying to learn how to edit the XML manual. Tonight was the first night I've even had a chance to look at it, and it doesn't seem too bad. A few questions that probably aren't appropriate on the manual pages:

what is the preferred editing method/program? I'm using Morphon and its very slow (on computer .... MHz, ... RAM and OS .... ). P4 1.4ghz, 384mb rambus rdram, win2k. Not a slow machine, never have trouble with anything else I want to run (don't play games on this machine, so exclude those processer hogs)
- Morphon was preferred, but any text or XML editor works. Just keep to the DocBook format and it'll be fine.

Please split historical info from the uptodate project pages: the latter must be thematically organized.

My Genboard and LCD display currently:

36-1 crankwheel and crank trigger setup on spare (and dirty) engine block:

```[http://proton.shadowflux.com/vems/crank_sens_mtd.jpg]``` [1]

```[http://proton.shadowflux.com/vems/sens_block.jpg]``` [2]

```[http://proton.shadowflux.com/vems/sens_gap.jpg]``` [3]

```[http://proton.shadowflux.com/vems/crank_trigger_machined.jpg]``` [4]

Here you can see the TDC mark in the pulley aligned with the missing tooth. You are looking at the back of the pulley, so from this angle it would rotate counter-clockwise.

The TDC is 15 degrees after the center of the missing tooth.

..so we set up the sum of trigger_tooth + ign_tdcdelay for 195 degrees.

Offsetting 180 degrees is absolutely reasonable because max ignition advance is limited by ign_tdcdelay. 15 degrees of max ignadv is not enough. Actually, ign_tdcdelay should be at least 30 crankdegrees larger than ignition advance at cranking. Common ign_tdcdelay values are 55..65 degrees.

igntdc_delay=0x1e (30 decimal, that is 15 crankdegrees) is very bad, see above. trigger_tooth=00 and igntdc_delay=0x1e, at n[]=0, the coil would fire at TDC, yes. But you might not be happy with max advance of 15 degrees, and timing from previous tooth would be active even for very low RPMs (where RPM variations are significant => BAD for dwell precision at lowRPM).

let's assume a normal tooth=10 crankdegrees (=360/36 if it's 36-1)

We are using 36-1, so tooth-tooth spacing is 10 degrees.

trigger_tooth=0d (decimal 13), that is 13*10=130 crankdegrees because one tooth is 10 degrees.

trigger_tooth=00 means the tooth after the missing tooth will act as the trigger. Please correct it whereever you see it wrong.

ign_tdcdelay=82 (decimal 130, which is 65 degrees)

This results in realistic n[] values, if TDC is 130+65 (=195=180+15) degrees after the first tooth after missing tooth. Adjust trigger_tooth in the first place, and only fine-tune with ign_tdcdelay (you can keep it in 60..70 degrees range, which is ideal)

Mik uses a similar missing-tooth placement.

```[http://proton.shadowflux.com/vems/crank_trigger_mounted.jpg]``` [5]

Okay. Thank you for the elaboration, it makes much more sense now.

The VR sensor should be mounted as close as possible to the trigger wheel, right? I haven't measured, but I'd say mine is about 1mm max from the trigger wheel.

Intake Air Temperature Sensor

I have used EasyTherm to modify the .inc files, but when I then test the sensor, it is always reading the same temperature range. If the sensor is not plugged in, I read 77C constant in Megatune. When the sensor is connected I read between 25C and 27C (when ambient is 68F. 26C is ~78F). Temperature varies proportionally when I adjust the ambient temperature conditions. I have measured the delta, adjusted my values in EasyTherm but still no change in readings! This is very frustrating. Which of airdenfactor and matfactor is the IAT values in?

Probably you are aware, but it worths to stress: MegaTunix (and MegaTune) reads the raw sensor values from GenBoard, and uses it's on tables from disk, not the tables that were compiled into the GenBoard firmware.

This independent lookuptable approach looks a bit stupid first (and somewhat inconvenient to take care of consistent configuration in 2 places), but it allows to fine-tune (calibrate) the tables with only rough initial tables in the firmware, and just reflash the ECM once, when it all looks good (not reflash it several times).

Update

Yes I was aware of that, but I was copying them to the wrong location under Megatune. Located the correct directory and now all works fine. Thanks for the tips. The seperate locations setup is a good one because it takes a few minutes to compile and upload the firmware whereas just copying the inc tiles to the MegaTune directory is very quick. I think I have my values down now.

Using Bosch air temp sensor, part number 0 280 130 085. Sensor comes from a VW 1.8t 20 valve, small port head.

Values in EasyTherm are:

50F=4800ohm

82F=1900ohm

208F=230ohm

Still have to test these values to be certain but thats what I have now. I believe these are +/-2F of actual temp.

I am now looking for sensors and other hardware.

Two MSD 8224 (GM DIS) coils for the ignition. These coils have two blade terminals which control charging and firing, just like any other wasted spark coils out there.

I am using the GM ignition module as a mounting base - it is already built and provides connection to the coils. I pryed the back off of the module and ground the electronics out of it. I then wired the inside so that the Weatherpack connector wires directly to the coil blade terminals. I would have a picture of the inside of the base, but I didn't think to take any pictures before I epoxied it back together. duh.

Aqua colored lines indicate wires I added after removing the guts.

All others indicate already present internal connections. Pin A on 6-pin connector used for +12VDC, Pin B for charging/firing coil #1, Pin C for charging/firing coil #2.

Picked up a Ford (Echlin brand name actually) VR sensor and trigger wheel from NAPA auto parts. I will be having the trigger wheel machined flat on one side and precision drilled to bolt directly to the timing belt pulley on the crank. Those of you using the Ford VR sensor: which terminal is wired to which pin on EC36 for correct polarity?

Any VR sensor pinout info near EdisIgnition ?

GND signal VR-
primary_trigger VR+

It makes sense to verify with InputTrigger/TriggerLog even if it works (my connection, done according to the polarity in the docs was reversed).

Trigger wheel: NAPA PN# CSS304

VR Sensor: NAPA PN# CSS400

Notes:

[history of Samuel].