# megasquirt help! no RPM signal



## audiKID90 (Apr 10, 2007)

i have a 1.8l 8v with a k26 turbo set up, i have megasquirt II V3.0. and i have no rpm signal, i am running off the hall sensor with a bosche ICU and the stock coil. i have 12v on one side and a good solid ground on the other, and the signal wire in the middle. i have checked my ecu several times and RPM reads that way but when its hooked up to the car i have nothing. i checked the hall sensor out of 2 known good distributers and still have no success. can anyone help me im am running out of ideas and ive gone to far to stop now. please help any info is appreciated. 
i made my ecu according to megamanual and set it up for a hall/ optical. and with the stim it reads fine, could there still be a problem with my ecu?
please someone help in out of options!!!


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## need_a_VR6 (May 19, 1999)

*Re: megasquirt help! no RPM signal (audiKID90)*

You need to have it setup for 12v low to high: http://www.msextra.com/manuals...#hall
If it's not, then it won't work.


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## sdezego (Apr 23, 2004)

*Re: megasquirt help! no RPM signal (audiKID90)*

What Paul said ^
You can also check out this relevant thread
http://forums.vwvortex.com/zerothread?id=3215373


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## twardnw (Sep 25, 2006)

I pulled the RPM signal from pin 7 of the bosch ECU, no modifications were necessary


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## audiKID90 (Apr 10, 2007)

thanks a lot guys for all of your help, i tred searching for stuff like this on this forum but i must have missed the tread. ill try that when i get home tongiht and hopefully it starts


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## audiKID90 (Apr 10, 2007)

*Re: (audiKID90)*

okay so i did a lot more research and i did some more tests. i put that 1k resistor as the pullup in and linked it to the signal as described in this http://forums.vwvortex.com/zerothread?id=3215373  and i still have no signal. so i tried a few other things like swapping out the bosch icu and installing a vb921 but i accidently bridged 2 of the pins and melted the vb921








so i removed it and went back to the bosch icu, and i have it wired up like this








and i follwed the hall sensor test on megamanual testing it with a LED and a 330 ohm resister and it was suppost to flash. but it didnt flash when i had 5volts hooked up to it, so i hooked up 12v and it flashed as a rotated the distributer by hand. so the hall is okay, so then i checked the voltage between the signal wire (pin #24) and ground after the resister, and i got a voltage of 5.49volts and 5.08v when i turned the distributer. but i still have no signal and im not sure why. does anyone see a problem with my wiring in that diagram? or is there something that im missing in all of this? please give comments and advise, im at a loss at this point.


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## need_a_VR6 (May 19, 1999)

*Re: (audiKID90)*

This is the diagram you need to use for the input:








If you don't have xg1-xg2 cut I'm not sure if you'll even read rpm with a VW hall sender. I know the above works for both 5v and 12v fed to the hall, but your 1k pullup has to match your hall input voltage.
Don't worry about the output until you get rpm, leave the coil unhooked for now.


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## audiKID90 (Apr 10, 2007)

in there under notes, when it says connect supply to hall sensor to pin 28, does that mean to run 12 volts to both hall and pin 28?


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## audiKID90 (Apr 10, 2007)

*Re: (audiKID90)*

ok so i tried it after performing the proper jumpes and stuff and i still have nothing. this is what i did.
jumped 12 volts from pin 28 to OPTOIN with a 1k resister








and cut xg1-xg2 and then jumperd xg1 to tachselect


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## vwjunkie42 (Jan 17, 2003)

*Re: megasquirt help! no RPM signal (audiKID90)*

same thing is happening to me


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## Svedka (Jul 4, 2008)

*Re: megasquirt help! no RPM signal (audiKID90)*









i used this diagram


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## need_a_VR6 (May 19, 1999)

*Re: megasquirt help! no RPM signal (Svedka)*

For most 'normal' installs you can't use that diagram as it moves the hall input to pin25 for his/MidnightGLI V2.2 mods. If you're using a V3 modded to msextra spec, then you still need hall on Pin24 and you just need to make sure your hall voltage matches where your optoin pullup goes.


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## jettagli_guy (Dec 12, 2007)

hi victor!!!


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