Originally Posted by woody
Exactly right Scott, I didn't say it would be easy.
I have been hunting around the open source scene for quite a while but
have alot of the dev tools for decompiling hex files etc so apart from the amount of time involved am not too phased by that prospect.
Yes, I have looked at piggyback systems and complete replacements like the open source Megasquirt project. I just figured that the high degree of systems integration on this vehicle may be cause problems if replaced in isolation.
How similar are the various Montronic ECU's? Obviously the maps, if not the programme code itself are all vehicle specific, but could I just get another ME2.8 (I think it is) from a more common vehicle to experiment on, as finding a cheap Crossfire or SLK ECU doesn't seem very likely.
Re. your posted graphs. Excellent! that is just the sort of think I want to log on the Crossfire and is my next step. Thanks for the link to VAG-COM but I have all the hardware/software sorted for this now (ELM/OBDlogger), I just need to get on and do it. Isn't VAG-COM exclusively for VAG vehicles as I know they use some slight variations on the ISO standard OBD spec.?
Its great to get some dialogue going on this stuff and it looks like we are finally going to start seeing hard data and figures appearing for this car; there has been plenty of talk but, dare I say, very little in the way of action.
Simon.
The ECU's have different code, checksum location, map location, and also physical differences. The processors inside can vary as well...although most are the same for a given ME-level. A ECU for this car is probably $350-$500 if you hunt around...the dealer will probably want $700-$900.
With piggybacks you retain the stock ECU, even full-out replacements still require the stock ECU for other functions. Have look at the SMT-6 from perfect-power.
VAGCOM is VW/Audi specific, it goes beyond the basic OBD-2 required parameters and gives access to hundreds of sensors, values, etc., plus allows recoding of some items depending on the car...kinda like the "star" system MB has. The producers are working on a BMW-specific tool that will give advanced range of functions, no idea when that will arrive. Access to things like fueling are not allowed, the way they are stored in memory is not directly accessible.
I'd be very interested to see some logged data from your car. If someone is local to me we could try to make a few graphs as well.
The scan tools are well worth the couple hundred $$ for the data they can give you.