Viper 550 ESP to 95 Explorer

The neutral safety switch wire, BLACK/ white, on the viper 550 must be connected to ground for the remote start to operate. When this wire is grounded, the alarm thinks the vehicle is in park or neutral and allows it to start. If it isn't grounded, the alarm assumes the vehicle is in gear and will not try to start. It must be connected to ground on this alarm.

The remotes need to be learned to the brain of the viper 550. They could have gone out of sync with the brain if they were not used for a while, assuming this is a used unit or the remotes are not the ones that came with this brain from the factory. You need to follow the remote learn procedure in the back of the install manual and program the remotes to standard configuration. This should solve that problem.

The starter kill relay is not necessary. Also, make sure the hood is locked when you try to remote start. Ground on this grey wire will prevent the alarm from starting.

As for the tach, if it is not hooked up, the vehicle will start and then immediately shut off because the brain cannot see the engine is running. The tach wire can also be hooked up to one of the two fuel injector wires on any one of your injectors. Usually, all your injectors will have one wire that is the same color on all the injectors. You have to hook up the tach wire to the other color wire on one injector, not on the common color wire. If your fuel injectors happen to have the same color wires, the one that reads AC voltage while the engine is running, and increases in voltage as engine speed does, that is the correct wire. Then, you must follow the install manual to learn the tach. If all else is hooked up correctly, your truck should start. Also, if this a used alarm, make sure the brain is set to tach sensing in the "engine monitoring" feature in the program menu. It will not learn the tach otherwise. Hope this all helps.