Crimestopper 2015 starting problems.

Hi,    I recently installed a crimestopper 2015fm in a customer's 1992 gmc suburban (gasoline). At first, I had installed it in smart tachless mode, and it seemed to start ok in the shop, but since he took it out and the engine got cold, the truck wont start on the first, second or sometimes even third tries. The starter cranks very briefly each time, something like a half second, if that long. Customer says this is unacceptable, so I ran the tach wire out to the coil, and used the tach finder feature to confirm the source. I performed the tach learn, and then tried starting, and yet again, the starter cranked for about half a second, which did not do anything to start the engine. I then attempted to place the unit in timed start mode, but in attempting to do so, two problems arose. First, I could not get the alarm to accept buttons 3 or 4 for the third or fourth selections of 1 and 1.5 seconds of crank time, and second, even when set to .75s of crank time, the engine still only cranks briefly and takes at least 3 tries to start when even moderately cold.    Is there some sort of low-voltage cutoff that i'm hitting? The battery is at about 12.3V nominal, and dips to a 10.1V minimum when cranking. Should I be telling this guy to get a new battery... or is there another problem I may be overlooking? -Dan

I had the same cold start problem in a Caddy,  thought it was the car(had bad IRS), was the range farly short?  I will test  my unit in another car.  Call thier tech support, they are good.