Re: Real Time Tuning of GM EFI

[Tom Jennings <tomj@xxxxxxx>]

The whole process of EFI "burning" relies on side-effects of various
memory technologies, which if you're not in the business seem pretty
arcane.

>From the EFI's internal computer point-of-view, all of the memory types
are the same: they contain program code and data tables. The EFI
computer cannot modify the contents of memory.

The cheapest memories are ROMs -- read-only-memory. They are programmed
at the factory and are one-time-programmable; they cannot be changed at
all, ever. Most very-high-production stuff has program in ROM. (Until
recently...) GM (or whoever) sends a "map" of data to the chip
manufacturer who makes up 100,000 or a million ROMs for pennies each. 

Next-cheapest is EPROM, which is

erasable
programmable
read-only-memory

To write stuff in an EPROM, you take it OUT of the EFI box, erase it
with intense ultraviolet light (there's a clear window on top with a
sticker over it) then it can be programmed on a special box; you can
erase/program them about 1000 times before they go bad.

EPROMs are used for shorter-run products where the extra cost is offset
by the ability to make small batches. Cost is closer to a dollar. EPROMs
also have a limited data-retention life; 10 - 20 years. Sounds like
forever, but I've got vintage computers past that age... never mind our
vintage cars.


SO - the ROMULATOR (d'oh, the xtronics website top page says
"romuTator") is a device that PLUGS INTO where the ROM or EPROM would
go, and from the EFI's point of view, looks like an EPROM (or ROM). It
also connects to the laptop, which through hte magic of software is
loaded up to emulate the original EPROM. You can now modify the "EPROM"
and the EFI is too stupid to notice.

When you're done tuning, you'll have to either leave the ROMulator
installed all the time (unreliable, inconvenient an expensive) or find
someone to burn an EPROM with the tuned-up contents of the ROMulator.

(Today, everything has changed; FLASH memory is soooo cheap that most
things use flash; it's an EEPROM:

electrically-erasable
programmable
read-only-memory

So circuitry within the EFI module can be externally turned-on to
program the thing. It means the EFI can be installed in the car --
COMPLETELY EMPTY -- and the very-latest-version of the EFI code loaded
into the car on the production line. Even though flash is slightly more
money than the cheapest ROM, the system cost is far less and even
dealers can do upgrades.

tomj


On Mon, 2006-03-13 at 16:06, mail@xxxxxxxxxxxx wrote:
> 
> " by using a cheap Laptop , a ROMulator II,
> " and an upgrade for your TunerCat > you
> " can change the 'chip' information as you
> " drive > forget 'burning' a new chip outside
> " the ECM.
> 
> you would want to burn a chip ultimately, when you get all the
> values
> tweaked, so you don't have to run around with the notebook and
> romulator
> spaghetti floating around.
> ----------
> Andrew Hay                                  the genius nature
> internet
> rambler                            is to see what all have seen
> adh@xxxxxxxxxxxxxxxxx                       and think what none
> thought
> 
> 
> 
> ++
> 
> 
> Ok - 
> 
> There was another section on the site for 
> 'Flash Chip' installing & burning
> which is a 'nuther animal entirely, 
> but not the one that makes the correction 
> to the Factory unit - In Real Time -.
> 
> Also, Craig Moates 'version' requires 'chip burning' . 
> Including the URL to his methodology in this article
> blurs the mind set. 
> 
> 
> 
> For the Real Time process, 
> unless I'm missing the boat, 
> you  plug in the laptop equipped with the Tunercat software and 
> Romulator II program to your GM ECM, put the vehicle thru its' paces,
> make your corrections, double check, hit save and unplug
> from the ECM.
> 
> 
> 
> Here is the Quote:
> \\\\\\\\\\\\\\\\\\\\\\\
> 
> In the 5 years I have been involved in GM EFI, the number one 
> obstacle to making GM EFI user friendly was the process of having to 
> make numerous calibration chips to tune a system. 
> 
> Well making chips to tune GM EFI is now history. 
> 
> There are new products on the market enabling instantaneous changes 
> to a GM EFI calibration with the engine running.
> 
>  This allows immediate analysis of the engine response to the change 
> which in turn allows immediate correction of the calibration. 
> 
> These products and the WINALDL program are revolutionary in the GM 
> EFI world.
> 
> On a recent weekend, I had the opportunity to tune two EFI vehicles 
> with my laptop. 
> 
> The first was a l969 4-cylinder Ford Escort for which I had built a 
> GM EFI kit. 
> 
> The second was a l988 Chevy truck with a twin turbo-equipped 350 
> engine.
> 
> To tune the Escort, I purchased a Romulator II from www.xtronics.com
> and purchased Tunercat's (www.TunerCat.com) RT (realtime) software 
> upgrade. Xtronics and TunerCat collaborated to create a system that, 
> in theory, is supposed to allow realtime tuning of GM EFI, which 
> means that no chips are burned to make calibration changes.
> 
> 
>  The Romulator device mimics a GM EFI chip and allows the "chip" 
> contents to be changed while driving with a laptop.
> 
>  To my amazement, it worked! 
> 
> Not only did it work, it worked better than my expectations.
> 
>  I could slide a mixture control parameter across my laptop screen 
> and immediately see the engine respond to the changes.
> 
>  For ex., I adjusted the idle mixture and watched the map sensor 
> value drop to a minimum. 
> 
> This is the same procedure as adjusting for the highest vacuum with 
> carb idle mixture screws, but without having to so much as raise the 
> hood of the car. 
> 
> In my DIY manual, I will describe the procedures used to tune a GM 
> ECM with a RT Tuning setup. 
> 
> Also, checkout Craig Moates site (www.moates.net) for alternative 
> products. Craig's AUTOPROM does emulation, ALDL data logging, and 
> chip buring all in one package.
> 
> On the Chevy truck, I used Accel's Gen VII DFI software. 
> 
> My customer had already installed and run his truck with this system. 
> I spent a couple of days struggling with this setup. 
> 
> Let me just say here that GM EFI with the Realtime Tuning software 
> beats Accel's DFI setup hands down!
> 
> An interesting bit of info is that using a Romulator with a pre-1996 
> GM ECM, you can edit the calibration while driving. 
> 
> The newer GM PCMs use on-board flash chips which means the 
> calibration can't be changed while driving. 
> 
> So the older ECMs with a Romulator are actually better technology 
> than the newer ones, which is good because the older ECMs can be 
> retrofit on older engines whereas the new PCMs can't be retrofit 
> easily.
> 
> 
> 
> ++
> 
> 
> Bt
> 
>      
> 
> 
>