mpg meter

[MVincken]

Hi,

I swapped an 1991 e30 m42 engine into my 1987 e30 316 (carburetor car)
these old e30´s had a different engine connector, with a loose connector for the rpm and mpg meter.

I connected the rpm and it works fine.
but i can´t get my mpg meter working... when i start it goes to the right and stays there.

my car (´87) has the top round connector, and the mgp signal (verbrauchsignal) is on the seperate connector on the left.

my engine (´91) has the bottom round connector, and i can´t find a pin where to connect my mpg wire...

does any of you know what pin/wire i need?

[varg]

Pin 17 on the ECU goes to the MPG meter by way of pin 8 on the round connector C101 according to my diagrams, so if you tap in at pin 8 of C101 you should get your signal.

[MVincken]

ok thanks, will check if it works.

in the list it says that 8 is the injectorsystem.
so i thought it was the injection signal for diesel cars

[varg]

ok thanks, will check if it works.

in the list it says that 8 is the injectorsystem.
so i thought it was the injection signal for diesel cars

Yeah, "einspritzsignal-injection signal." The english pinout chart for the ECU says "fi measurement signal" and the block diagram in the troubleshooting manual says "Present fuel rate output." These are close enough in meaning to me that I'm confident that it's correct. If you want to verify independently, check what the output from pin 8 of C101 looks like with an oscilloscope. Should be a 5v square wave. Whether or not the mpg meter will be accurate is a different matter, from what I've read they're different in pre and post '86 cars, they're likely different in carbureted cars too.