No rpm signal pickup from stock ecu

[maddios]

Hey guys, i posted this message in the ignition troubleshooting board but i figured i'd ask here as well.

I just finnished assembling my MSII v3 to run as HALL sensor pickup, i rechecked the board twice and it looks good (no shorts). I'm running software v2.36 on the MSII.

Here's the problem: The MSII works great on the stim, but i partially wired it into the car yesterday and i dont' get any rpm signal coming in when i try to use the bosch motronic tach signal (which goes to the gauge cluster). The ecu is from a 1991 BMW M5, and when i test the tach signal i get ~48Hz at idle which shows as 10.5v. I hooked up just the following wires: Ground to the same spot as the motronic grounds to, 12v to the same spot the motronic gets its ignition +12 from, and the pin#24 to the tach signal. Am i missing some wires?

Or do i HAVE to tap into the hall sensor (got one as a cam sensor)?

Thanks guys

[S.Bretz]

try NOT using the tach gauge wire. Most guage that I have dealt with (not many) have had a 0-5v signal to turn the needle. The 0-5v was based off a tach IN signal. That is probably what you should try to hook into....a TACH IN to the ecu...no the tach out to the tachometer.

[maddios]

heh i'll try, i'm just afraid of tapping into it, as the ecu is picky and i tried it once and the ecu started acting all weird (burnt a coil)

I was trying to wire in a remote start, and i guess the unit was putting noise onto the line.

I guess i'll try to tap the Hall sensor line from the cam and see what happens. As the main tach is VR i think

[maddios]

well i've resolved this issue heh, i just went ahead and switched the MS2 to VR pickup and hooked it into my sensor. Works good now, just reads WAYYY up lol

I'll try to get 2.672 code on it, just to play around, MS2 won't be controlling anything for awhile until i fully understand it.