Re: Mercury Marine diagnostics?

I'm posting this message to myself, hoping that others might know
something about this.

I found out from
http://www.andywhittaker.com/ecu/aldl_hardware_cont.htm and
http://216.230.203.183/marine/marine.htm that Marine GM ECUs and
Mercury Inboard/Outboards use the same interface, and that this is
the same as the ALDL interface the Lotus Esprit uses, and that this
interface really is an ISO-interface where only the Ground and K-line
are in use. The power for the interface obviously can be taken from
the onboard battery, or from an external power source.

Can anyone tell me what DDT terminal is the K-line and which one is
ground (the terminals are called A and B)?

I connected my test-ECM and a working Jeff-interface to a power
source and a Linux-box, compiled freediag, and here is the output I
sometimes got when connecting DDT terminal A to ISO K-line and DDT
terminal B to ground:

scantool> watch raw
Waiting for data to be received
msg 00 src 0xbf dest 0xff msg 00: 0xff

scantool> watch nodecode
Waiting for data to be received
1069715148.1448: msg 00 src 0x0 dest 0x0 msg 00: 0xfe

If I swapped the DDT-terminal wires around I got no output.

So I guess the set-up is OK, or is this just noise on the line?

If the physical stuff is OK, I only need the software.

Anyone?

Regards, Georg

=====

--- In opendiag@yahoogroups.com, "georg_eie" <opendiag@g...> wrote:
> Hello everyone!
>
> My name is Georg, I'm 34 years old and live in Norway.
> I've just joined the group.
>
> Does anyone know anything about diagnosing Mercury/Mariner marine
> engines? There is a proprietary tester (DDT) that costs about
$1000,
> and it connects to both their inboards and outboards. The software
> cartridge has to match the specific engine. Such a cartridge costs
> about $50, so to diagnose more than one type of engine can be
pretty
> expensive.
>
> I am looking for an cheaper way of diagnosing my outboard (1999
> Mercury 225 Optimax), and if need be write the software for it
> myself, but as long as I know practically nothing about the
> electrical interface, I really don't know where to start.
>
> I have a broken 1999 200 Optimax ECM. It is contactable and runs
the
> engine on four of six cylinders, so it should be good enough to
play
> around with. Markings: VA005481 Motorola Mercury Marine p/n 857127
> EFIS69801 09-04-1998 200 DFI ECM 99MY 857127 1 PI82670705.
>
> The DDT connects to the ECM with only 2 wires, and none of them are
> connected to ground or vcc, so my guess is that it is some kind of
a
> current-loop interface, but that's only speculation.
>
> The IC that these two wires connect to is an eight-pin National
> Semiconductor thing marked 83AY 52T09, but NS claims that they
don't
> know anything about this chip. Must be a custom made chip or
> something.
>
>
> All tips and hints will be greatly appreciated.
>
>
> Regards,
> Georg

 
Received on Mon Nov 24 15:53:07 2003