bryan01 Posted May 15, 2007 Share Posted May 15, 2007 where is it? i'm wiring my megasquirt and i need an rpm signal wire. i wired the squirt up to what i thought was the rpm wire and everything else seems to be working but when i try to crank it it stay's at 0 rpm even thou it's cranking. i've got an ecu pinout and i tapped into the wire i thought was the tach signal, but nothing happened. i then came on here and checked and tapped a wire off the white interior plug that someone said was the tach wire, same result. i saw from a few posts that the autometer tach's tap off of a wire in the engine bay, does this wire corralate directly to rpm? help Quote Link to comment Share on other sites More sharing options...
Z U L8R Posted May 16, 2007 Share Posted May 16, 2007 use either of the two 120 degree signal wires, i can't remember if it's green or white but either 120 will work. Quote Link to comment Share on other sites More sharing options...
bryan01 Posted May 16, 2007 Author Share Posted May 16, 2007 + 10000000 points hot damn, it cranks and has rpm ... it's cranking at ~145 rpm's if anyone wanted to know ... anyways, i'm getting fuel flow thru the injectors now (before i wasnt getting any flow b/c the MS didnt know it was cranking due to 0 rpms) ... now i just have to figure out what the cranking pulse width needs to be and watch it fire ... let ya know when it does. thanks again man, and you should come by sometime, i want a ride in your 400hp beast ... Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted May 16, 2007 Share Posted May 16, 2007 i am dealing with the same thing, but mine is with a haltech.One of the wires is the 0 degree and the other is the 120 so for now i have the 0 set as my home and the 120 set as my trigger. It fires the coils but its not timed right yet, i have to find out myself how far its off so i can adjust it in the haltech. let me know how far yours is off and i'll do the same Quote Link to comment Share on other sites More sharing options...
bryan01 Posted May 16, 2007 Author Share Posted May 16, 2007 what do you mean how far it is off? the difference between the 120 trigger and when it should actually fire? i'm not actually using this wire to trigger an ign system. my megasquirt is fuel only, but it needs a correct rpm signal to tell it to start working and to help calculate how much fuel it needs. Quote Link to comment Share on other sites More sharing options...
scottyMIz Posted May 16, 2007 Share Posted May 16, 2007 ohh ok, i was thinking that you were using it for ign too i'm not sure how far mine is from being timed right i haven't had time to touch it in the last few days and i dont have the intake on it right now. So i'll have to wait and see how much it's off. Quote Link to comment Share on other sites More sharing options...
bryan01 Posted May 21, 2007 Author Share Posted May 21, 2007 ok instead of starting a new thread, i'll just use this one... so i found my spark. (see other thread about me losing it). my fuel computer (megasquirt) needs a RPM signal to run. the stock ecu needs a RPM signal to fire spark. when i tap into either of the 120 deg crank angle sensor wires going to the ecu i get the RPM signal to the megasquirt but it disrupts the signal back to the ecu somehow and i lose spark. are they're any other wires i can tap into to get an RPM signal? or is there a way i can tap into it that'll send the same signal down both wires (one to the stock ecu and the other to the megasquirt) w/o degrading either signal? i ran my car today, briefly. i cranked it with the megasquirt hooked up, so fuel was pumping into the engine, but no spark, then i cut the wire, and it fired and ran with the fuel that was already in the cylinders (for about 5 seconds) and then shut off ... i was so excited ... but anyways ... any other ideas? Quote Link to comment Share on other sites More sharing options...
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