Hello Theo
How are you, the new software is very good , I have another question , I hope
you may be able to help me with , do you know how the original system generates
a signal to the dash pod for the fuel kilometers consumed , my electrical
drawing does not show it , and cannot see on the electrical plugs where the
electrical connection is ,as it has stopped working , it used to work well. My
wiring is showing different to the manual .
Thanks in advance
Best Regards
John Gill
cell 0412 084 004
Fax (61) 7 3389 2508
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Hi John,
Yes, all is fine on our side of the pond. Just started to get warmer and spring
is in the air.
The digital dash has a microcomputer inside. It uses car-speed from the speed
impulse (sender depends on MY) and load from the ecu. I’d have to look which
path the signal takes, but from head it is the load that is monitored. These are
calculated and used to estimate the fuel consumption.
regards
Theo
1992 Porsche 928 GTS Midnight blue
The Netherlands
http://jenniskens.livedsl.nl
http://928gts.jenniskens.eu
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Thanks for that Theo
By load signal do you think it is voltage related , i.e. can be measured , I
cannot for the life of see where it is taken from the ecu , it is certainly not
in the place as indicated on the schematics.
Best Regards
John Gill
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Hey John,
Somehow I was at this station before… I remember looking for the same issue.
Apparently you forget when you get older ?
It is not load but the actual injector pulse. It reads the injector pulse
duration from the trigger point at the injectors (L89 , not #2, label N26) and
that N26 is connected via the CEB (W12-Q23) to pin 8 of plug 4 where it says
Jetronic. Nice …. They could have said “injector pulse for measuring fuel
consumption” and a think Jetronic is a somewhat short version of that.
Yes, load can be measured, but is a 10uS impulse, so you need a scope for that.
The dash evaluates the injector pulse by looking at the PWM, Pulse Width
Modulation. Clever device eh…?
regards
Theo
1992 Porsche 928 GTS Midnight blue
The Netherlands
http://jenniskens.livedsl.nl
http://928gts.jenniskens.eu