weird tach problem

im installing a 791XV in a 2005 E350 van and added magnetic door switches for the side door..but anyway the whole alarm is fine and i have everything hooked up but one problem, the starter output is not outputting anything when i remote start.  and its not the hoodpin or brake wire or ground or anything, everything is hooked up fine.  heres the weird part, when i disconnect the tach wire...in tach mode or tachless mode..it will crank, but of course not start cause tachless mode wont work on this vehicle and in tach mode, the tach is programmed..but when i disconnect the tach, it just cranks and thats it.  i called DEI and we established that its a tach problem. i got the WHITE/ pink wire at the PCM just like the sheet said and it programmed fine to the unit.  i even moved the tach twice and metered it..fine..programmed it..fine, but still no output on the starter wire till i disconnect the tach wire, then it cranks but wont start.  this is the weirdest thing ive seen in a tach problem.  ive seen bad tachs cause the vehicle to start and die, or just crank..but NEVER have seen it to cause the alarm to not output on the starter wire.  im thinking its a bad brain.  the customer is coming back wednesday so i was wondering if any of you have suggestions?  thanks

Can you use alternator sense on this model ? Try it and see if it works.Jeff

Velocity Custom Home Theater

Mobile Audio/Video Specialist

Morden, Manitoba CANADA

Catch tach off of a fuel injector

yes this is the same post as before, i had to repost it cause i got like 2 replys and then the post went so far down the list that no one read it.  bmnicolosi, i tried fuel injectors already.  hey Jeff im not sure what you mean by alternator sense.  i never knew you could tap a tach signal off an alternator before...but then again it makes sense.  only thing would be that the AC voltage would be a very high reading..im worried that might damage the alarm.