[Gmecm] Trip computer data defention

[Andrew Hopton]

Copying from my Camira Manual (JE supplement), the description of the A2
signal is as follows:

"The ECM sends a square wave signal to the trip computer.  The pulse width
of the signal changes according to injector pulse width.  With engine not
running, it should be close to 5 volts. With engine running, the voltage
goes down with increased injector pulse width and frequency"

I take the last bit to mean the observed voltage as measured with a basic
multimeter - in other words the signal is apparently pulled low (0V) when
the injector opens and goes high (5V) when it closes. (The Camira is a
batch-fire ECM - all inj are fired simultaneously)

The diagrams in my manual show that VSS output is also fed to the trip
computer.  This gives it distance and speed info, the ECM signal provides
fuel usage info.

Incidentally, if you want a copy of (any part of) this manual, contact me
off-board.

Cheers.

-----Original Message-----
From: gmecm-bounces at diy-efi.org [mailto:gmecm-bounces at diy-efi.org] On Behalf
Of Dave Hall
Sent: Tuesday, 5 April 2005 8:12 AM
To: gmecm at diy-efi.org
Subject: RE: [Gmecm] Trip computer data defention

I'm interested to know too - there could be a couple of options, but I
haven't measured anything yet.

It could just be the injector signal before the final output stage (minus
ringing & other effects), could be a separate oscillation out with frequency
related to injector pulse width, etc etc.

If noone has the info, I may do some measurements to find out :)

Cheers,

Dave

-----Original Message-----
From: gmecm-bounces at diy-efi.org [mailto:gmecm-bounces at diy-efi.org] On Behalf
Of Andrew Huxtable, IT Support, Lonsdale
Sent: Monday, 4 April 2005 7:44 PM
To: gmecm at diy-efi.org
Subject: [Gmecm] Trip computer data defention

Hi,
	Does anyone have any info relating to what sort of info comes
out and the format of the trip computer output pin(A2) on an 808/165
(or any for that matter, they might be the same?)

I'm looking at options for a transplant Trip computer into my car that
does not have one. Or possibly to make one.

Thanks,
	Andrew

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