Author Topic: rpm output when engine off.  (Read 7543 times)

Offline mr_g

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rpm output when engine off.
« on: June 05, 2009, 08:05:07 pm »
I have found out, when the engine is off, rpm outputs the signal like 10 time lower frequency, cca 100rpm... My response was: WTF!

Does anybody know anything about this?

Offline lost

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Re: rpm output when engine off.
« Reply #1 on: June 05, 2009, 10:01:46 pm »
TRY to use coax cable or sometihing shielded. got the same problem of ghost rpm with standard 1mm 2 wires when turnig key to acc on after few seconds.


Offline gunni

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Re: rpm output when engine off.
« Reply #3 on: June 06, 2009, 03:13:25 am »
If you have cut the 12v to the ecu then it´s not possible.

Offline mr_g

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Re: rpm output when engine off.
« Reply #4 on: June 06, 2009, 02:48:15 pm »
ECU has 12V, because I'm starting it up. But I have just added ignition signal,with no cranking, and engine isn't started. But VEMS is supplying 100rpm (cca 1.5Hz) signal on the rpm output. After cranking and starting engine, I would get about 10 times higher frequency, about 1000rpm (cca 15Hz)..

Offline gunni

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Re: rpm output when engine off.
« Reply #5 on: June 06, 2009, 04:31:00 pm »
I have not had that happen.
Might want to up the pull-up resistance

What is it now?

Offline lost

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Re: rpm output when engine off.
« Reply #6 on: June 06, 2009, 04:59:03 pm »
you get some interferance. from hi current wires to lambda or injectors. try removing all fuses except vems supply fuse and then check rpm for ghosts :)

Solved same problem with some hi quality coax. from vems to rpm trigger. I was getting for a few seconds like 300 400 rpm  but onley with the lambda fuse connected. and engine was off!


Offline lost

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Re: rpm output when engine off.
« Reply #8 on: June 07, 2009, 01:39:36 am »
So it's wbo2 heater creating interference?

yes.