I'm in the process of installing my A1000 pump and need to know a few things. How many volts does the pcm send to the pump? I had problems with this pump on another car that only gave 7-8v at idle then the full 12-14v at higher rpms. Also, when does the pcm give power to the pump? Is it always on with the ignition on or does it click on for a sec to give pressure then turn off until the the engine cranks? I also had problems with this on another car. Seems like the A1000 is popular for not holding pressure.

Thanks for any info

 

The PCM does not feed voltage directly to the fuel pump. There is a +12V power relay, that is activated by a signal from the PCM. When the pump is "on" it should always receive system voltage of +12V or more. There is no case where the power supply provides anything less than available system voltage.

The PCM turns the fuel pump on when the key is turned to the on position. If the engine is not started, it shuts the pump off. The PCM looks for the low resolution pulse from the Optispark, and if it can't find it, it shuts the pump and injectors down. Only when the engine starts will the pump restart.

You might want to bookmark the wiring diagrams on Shoebox's website... its for a 95, but you haven't bothered to tell us what year your engine is:

http://shbox.com/1/4th_gen_tech2.html#1995_pcm_wiring

The fuel pump is on drawing #3.