quote Originally posted by Will: Why get an aftermarket ECM at all?

Are you paying attention to what this thread is trying to accomplish? I think you should read the first page again.

edit - woooooohoooo page 3
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This sig sucks

[This message has been edited by IEatRice (edited 05-15-2005).]

quote Originally posted by IEatRice: Are you paying attention to what this thread is trying to accomplish? I think you should read the first page again. edit - woooooohoooo page 3

You've discussed your computer hardware, but it's pretty pointless without some pretty radical ENGINE hardware to go along with it.

As much into computers as you are... Why don't you write your own program for the stock Fiero computer? Or a more heavily hacked computer like the 7730? You would be starting with hardware that's already designed to to what you want to do, but you could write the software to do anything that you want to do (within reason). You could put the ALDL datastream into a USB format for instance...

quote Originally posted by lou_dias: Some thoughts... A harddrive mounted vertically should last longer than once mounted horizontally. Also, how about using the new Commodore 64. It is powered by a 16 bit 65816 cpu that runs at 16-20Mhz. It's serial, parrallel and CIA(joystick) ports are easy to read in real-time and is a system easy to program for. Less cooling issues also. The stock Fiero ECU is a dog. It only makes fuel adjustments every 100rpm and timing adjustmenst every 500 rpm. The big kicker there is the timing adjustments. Even if you keep the fueling the same, improving the timing adjustments would make for a smoother motor and would net you a bit more fuel economy and hp. Maybe splicing the injector harness you can also program in a sequential injection firing order... Also, finally add a knock sensor to the v6 block... Years ago I came across a website that had programatically disassembled the Fiero ECU down to the raw computer code logic. Don't know what the link is anymore but that should be the starting point. ps, The old C64 had a cartidge port. There were cartidges that offered EPROM adapters. An eprom could contain all the code and lookup tables. This allows for future mods just by burning a new EPROM just like is done now but would also change/upgrade the program code too. As I recall, the stock Fiero ECU is still a dog compared to the original C=64.

the comodore 64 was famous for it's overheating after 15 minutes. You sure? Anyway, all of the ideas so far are less capable and more expensive and complicated than just buying a megasqurt preassembled with a harness for $400 ad a few ford parts and you can go DIS to boot. You would still benefit from stuffing a PC in the car, as the megasquirt can be programmed live. You can tune it as you drive the car. It understands boost also, which is a real perk.

Ahh, but for less than $40 I can get me a 1227749, 1227730 or 1227727 General Motors PCM that will run circles around anything in the aftermarket, and its fully programmable with a $45 eprom burner.
The Sy/Ty or Turbo Grand Prix code is leagues ahead of anything aftermarket for boosted applications.
Add a $200 emulator and you can program it in real time as you drive.

But the kicker that makes this the only real solution is the fact that you retain the GM diagnostics system built into all of their PCM's. Without it you cannot easily monitor the output of sensors on your engine. It is this diagnostics system that makes tuning EFI a fairly easy task, and I pity the person that has to tune an EFI system without it.

There is also the matter of the nice trouble code that flashes up alerting you if something happens to go awry with your engine management: You can say goodbye to that convenience with any aftermarket system you use.
If you live in a state that requires a catalytic converter, you can forget about running anything but a GM PCM, as its code features that permit running a cat conv without destroying it would be gone. GM code offers altitude compensation, and in most applications there are substantial fuel economy enhancements. It is next to impossible to replicate these features with even the most expensive aftermarket EFI system.

If you ever happen to have a catastrophic failure of an EFI sensor or the PCM itself, there is a built in failsafe limp mode that will get you back home. I could go on, but I think you get the idea...

[This message has been edited by Mick (edited 05-17-2005).]

I believe Megasquirt and Accel DFI both have altitude compensation...

Really, there's no excuse for a MAP based system NOT to have altitude compensation.

quote Originally posted by Will: I believe Megasquirt and Accel DFI both have altitude compensation... Really, there's no excuse for a MAP based system NOT to have altitude compensation.

I know the MS does. It takes a free-air reading just before startup. The MS2 has support for dual MAP's, for on-the-go altitude compensation, if you're taking long trips.

Most GM code has at least 8 different tables that specifically address altitude compensation. Your fooling yourself if you even think for a minute that a megasquirt system can approach that level of code sophistication. The megasquirt II addon board, which itself is about $80, is still only a baro normalization system; which is not even comparable to GM's altitude compensation.

[This message has been edited by Mick (edited 05-17-2005).]