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Reprogramming fuel injection modules

  1. Jul 18, 2004 #1

    Ivan Seeking

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    I have a buddy asking if I can do this for his 300 ZX. I have checked and there is a programmable module available with software, but apparently some companies [one at least] are reprogramming the factory chip directly. Does anyone know where to get the code, or at least what values affect various parameters, and if this can be done without too much difficulty.
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  3. Jul 19, 2004 #2


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    I'm curious about this as well - just being able to reset the "check engine" light would save a bunch of money. And it would be neat to see (and, of course, mess with) the way the engine runs.
  4. Jul 19, 2004 #3

    Ivan Seeking

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    Here is the programmable module that I found. Also, that was a 350Z, not a 300. [I'm getting old I think...]

  5. Jul 19, 2004 #4


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    Hmm, here's my two cents.

    First off, a big change occured in 1996 with OBD-II (On-Board Diagnostics V2) becoming standard on vehicles here in the US. It standardized things tremendously so you can buy hand-held devices at an auto store that lets you monitor RPM or emissions controls or now the car nanny as a data logger with a USB port for fleets or concerned parents to see what's happened over time.

    The 300ZX went away in part because of OBD-II as did the Supra and ZR1. So it would be OBD-I or maybe some proprietary protocol before then.

    Regardless, its a serialized data stream. For my 1996 Pontiac, I've got the LT1 engine and a programming interface that lets me use a regular serial port to interface with the OBD-II port for resetting codes and viewing some data in real-time. Its a very basic little module but since I have little interest in reverse-engineering it I haven't even cracked the case on the little 1"x1"x.5" box. It is hand-made and purchased off some guy online 4 years ago with some software it looks like he developed in Delphi by the interface buttons.

    My guess is that the data is available but slightly difficult to assemble. The new premeire programming package for the LS1 GM engine is like $750 for a single car licence and $5000 for an unlimited licence. Its really basic in terms of just showing the raw data maps (a grid with numbers) and has none of the nice features that can be had with aftermarket engine computers and accompanying software like the Accelle DFI or FAST setups have. A qualified and educated user would be really handy as the program isn't exactly point-n-click. If I wanted to change the temperature correction factors or increase the pulse-width from 3500-5500RPM because the wideband O2 showed a lean condition on the dyno I wouldn't have much of a clue where to start. If the information on how to program the computer were freely available, I would imagine competition would have figured out a way to make a cheaper better interface, there are a lot of Corvettes, Camaro/Firebirds and now street rods with the LS1 engine and GM computer.

    But with the magic of free info exchange on the internet, who knows. Someone in Japan might have published a schematic for a $15 serial interface with GNU software to program the Nissan computer. If you would happen to find something like that, please post or PM me with the info, I have a friend with a project involving a skyline motor who could use any help he can get for his 'project'.

  6. Jul 21, 2004 #5


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    for Z anything (240, 260, 280, Z, ZX, 300 and 350) the only people you need is motorsport. I don't know much about doing the reprogram job, but I'm sure by now motorsport has a chip or replacement module. I know for the 280zx, you send the old brain, they send you a reprogrammed one, but big bucks.


    As to reprogramming fuel injection, I've been looking at this nifty little homemade job that seems to have some promise:
    Megasquirt: http://www.msefi.com/
    Megaspark: http://home.comcast.net/~tjhafner/MegaSpark.html

    And no, I have nothing to do with them.

    The lovely thing about the mega products, they can work on anything, I think I remember reading a line "From a lawn mower to an F1 car"
  7. Aug 3, 2004 #6
    Ahhh... I've spent a bit of time on this topic, particularly in relation to Zcars. It's a relatively simple procedure to pull out your ECU, desolder the ROM chip and put in a socket. You can then get some new chips, a program called RomEdit, a rom burner and some bin files and you'll be on your way.

    If you've got a z32 (1989-1999 or something) you'll be sweet as its mostly cracked. http://cherrypicker.tripod.com/ is a brilliant site and has everything you need.

    A Z31 (1984-1988) on the other hand... a few people are working on it at the moment, do some searching on http://z31.com/board/ and http://www.hybridz.org/ to see the current status.

    For other cars (obviously) it all depends. The Civic boys, for example, are doing crazy crazy stuff...

    Good Luck!
    (Wow, my first post wasn't a question...)
  8. Aug 4, 2004 #7

    Ivan Seeking

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    Thanks much everyone.
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