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starter relay

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=27284
Printed Date: July 20, 2025 at 3:23 AM


Topic: starter relay

Posted By: Evansturbo
Subject: starter relay
Date Posted: February 26, 2004 at 1:08 PM

   I got a remote start pager alarm 

   i want to turn off my fuel pump with this remote...but when i use remote start

   i want the fuel pump to be working again.

   on the alarm i have got   1 wire that comes from the alarm that sends a 

    negative pulse out when the alarm is turned on and another  wire that

     sends out when the alarm is turned  off.   the second wire  also  sends a

     negative   pulse out when  the car is remote started.

     i could use my  standard alarm  in  cojuntion with this   but....i cant find out

     which wires turn the alarm  on & off ...

                           cheers evans  




Replies:

Posted By: sparkie
Date Posted: February 27, 2004 at 3:35 PM
It's not advisable to disable the fuel pump. You could use the alarm's starter kill output to activate a relay to open the fuel pump's power circuit. The reason most installers only kill the starter circuit is that if something fails your vehicle won't lose power while driving. MURPHY was an optimist. Things break!   If your relay or it's connections fail while driving you could be left in a dangerous position if your engine dies. Most manufacturers have also issued service bulletins warning of potential problems or system failures when alarms interupt ignition or fuel pump circuits. The fact that relays use mechanical contacts inside them means that there is the potential for the relay contacts to slightly open with road vibrations. Manufacturers have also noted premature failure of catalytic converters from this condition. The best thing to do is to interupt only the starter circuit. If done well, this will prevent anyone from stealing the car. It MURPHY does pay you a visit, the worst that will happen is that you won't be able to start your car. If you still want to do it though use the starter kill output. Make sure to hook up the remote starter in such a way that you energize the fuel pump circuit after the relay so the car runs. Check the install instructions that came with your unit for details.

-------------
sparky




Posted By: Evansturbo
Date Posted: February 28, 2004 at 1:30 PM

  Cheers sparky,

                            Thats sound advice mate,   the only reason i wanted to this is because  my standard alarm aint working, and the 2 wires that goes into the standard alarm is red /blue which runs the fuel pump so i cut the wires and put a switch inbetween and used this for the imobiliser as it was already been done by vauxhall in the standard alarm.

                                     I wired the starter disable up so that when i use my remote to lock the doors the starter disable (wired thro a relay ) shuts my  engine off.... but then i cant remote start the car.   so i need a way of turning my   my feul pump or starter off when my doors are locked ...but to make it active again  when i remote start .

                       From the alarm i have got   3 wires spare to play with

                       (1)  a negavive pulse to activate the standard alarm

                       (2) a negavive pulse to turn the standard alarm off ......plus when the car is remote started there is a neg pulse to turn the alarm off when the doors are locked .

                         (3)  a starter disable neg pulse that comes on when the door is locked  and stays on till the door is unlocked again.

 with these wires is it possable to do anything  to sort my problem out

   No 3  wire can also be switched to work the other way round by going into the program.

  hope you can help          evansturbo  






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