hey guys a few days agi i was havning some probs with the car. i took it down south and it broek down to where i would not have any fuel pressure. then all of a sudden it would start the next day or so. then again driving it tongiht it quit on me while driving to where i had to furl pressure and it woudlnt start. so we start poking around the engine and try some testing. first off i have a Reds XP plus, billet FPR, and a hotwire kit on the car. now wiht a tester light we see that there is power going into the fuel pump relay but none going out of it. no power the the pump in the back either. so o ask a freind to try the relay out on his car to see if it works, nohting but a click. so a freind gives me his working one in his car to go get mine statred and get it home. i oput it in and go to start it up and boom the new relay blows. we go back to his car try out his new relay and now that one wont work. this whle setup gave me no probs for the past 8 months and now this. waht could casue the relay to blow like that? do i have a bare wire touching? if so would it be before the relay or after. i can get power to it just not out of it. any ideas would be great i need to get the car running soon.
Keep blowing fuel pump relays.....help fast!!!!
- Thread starter 1985GN
- Start date
salvageV6
Daily Driver
- Joined
- May 25, 2001
Relays only blow when too much current goes through the coil windings or the contacts.
I assume the fuel pump hot wire is fused and hasn't been a problem, the heavy wire.
Secondly do you use a voltbooster or boost a pump device? That would be the only way I can think of that increased voltage could get to the coil to blow it out. A snubbing diode acrross the relay coil is always a good idea.
I assume the fuel pump hot wire is fused and hasn't been a problem, the heavy wire.
Secondly do you use a voltbooster or boost a pump device? That would be the only way I can think of that increased voltage could get to the coil to blow it out. A snubbing diode acrross the relay coil is always a good idea.
I don't know about the relays, but I have had two things cause the fuse to blow. Maybe one of these could be your problem. First, years ago, I had the power wire that leads to the back from the hot wire kit ground out. The insulation had worn through, and occasionally it would touch and blow the fuse. The next problem I had was the plug that goes on the oil pressure switch. From getting oil soaked over the years, the rubber started degrading, and the plug fell off. Every once in a while, it would ground against the engine. Maybe something like this is causing your problem. Also, check your fuse. If the relay is going, maybe your fuse is not the right one. Good luck, and let everyone know what it was.
Brian
Brian
Racetronix
Well-Known Member
- Joined
- Oct 1, 2001
The relay's high current contacts should not blow (terminals 30 & 87), your fuse should (20A). The relay contacts are rated at 2-3 times (30-40 amps) the current demand of your fuel pump. It sounds to me like you have some bad or improper wiring.
Which relay keeps blowing, the factory relay or the hotwire relay?
Is this a homebrew hotwire kit or a commercially made unit?
A 'snubber' diode is not required unless the relay is being driven by your ECM (solid state driver). A diode is used to short the EMP so that it does not damage any solid state drivers. If the relay is 'clicking' / getting power to the coil (terminals 85 & 86) then the coil is OK. Most relays can operate at much higher voltages for extended periods of time without damage to the coils or contacts.
Jack
Racetronix
Which relay keeps blowing, the factory relay or the hotwire relay?
Is this a homebrew hotwire kit or a commercially made unit?
A 'snubber' diode is not required unless the relay is being driven by your ECM (solid state driver). A diode is used to short the EMP so that it does not damage any solid state drivers. If the relay is 'clicking' / getting power to the coil (terminals 85 & 86) then the coil is OK. Most relays can operate at much higher voltages for extended periods of time without damage to the coils or contacts.
Jack
Racetronix
