who444444
Well-known member
My fuel pump started to leak and so now is the time to install electric pump.
Decided to use the 85 prelude pump and found one at rock auto for under $30 ( I think )
I want to power it through a relay so I found a junkyard toyota 30 amp relay.
Here is how I wired it. (this is for the folks that might not have figured it out yet, everyone else skip on down )
I tapped into 2 of the 5 amp circuits as I wanted to separate the switching and the load on the relay. Both circuits are switched circuits only hot with key on.
So first circuit positive to relay post 85 and ground to relay post 86 ( run this ground to the oil pressure sending unit and land with the existing wire on unit )
second circuit positive to relay post 87A (on my relay or 87 on a 4 post relay) and positive to the pump from relay post 30. Negative of pump is grounded to frame.
post 85 and 86 connect inside of relay through a coil that when energized connects OR disconnects 87 and 30
I needed a normally closed relay that when energized disconnects and here's why.
when no power to relay, 87 and 30 are connected ( that's OK because there is also no power feeding the pump because the key is not on )
With key on and engine is not running oil pressure light is on because sending unit is grounded and now relay is grounded (and energized ) and relay now disconnects 78 and 30 (the pump circuit.)
When engine runs and oil pressure light goes out it is because the sending unit losses ground. When relay losses ground 87 and 30 are connected and pump is powered. (Whew!)
I run a single carb and I dont think I will need the pump running to start my bike because there is a lot of fuel in the carb float bowl.
If it turns out I'm wrong I will put a switch in the ground wire going to oil sending unit to temp brake circuit and close relay before starting.
Why run like this through relay you say? Just a kinda safety feature so if the bike is not running the fuel stops flowing just like a manual pump.
Anyway, had to cobble up a bracket to mount pump and also block off opening where old pump was. Made that today and hope to finish mounting all tomorrow.
Here's some pics. flat black on the bracket and once I know the pump is not dead out of the box it will be flat black too. To match the rest of the bike. :smilie_happy:
Decided to use the 85 prelude pump and found one at rock auto for under $30 ( I think )
I want to power it through a relay so I found a junkyard toyota 30 amp relay.
Here is how I wired it. (this is for the folks that might not have figured it out yet, everyone else skip on down )
I tapped into 2 of the 5 amp circuits as I wanted to separate the switching and the load on the relay. Both circuits are switched circuits only hot with key on.
So first circuit positive to relay post 85 and ground to relay post 86 ( run this ground to the oil pressure sending unit and land with the existing wire on unit )
second circuit positive to relay post 87A (on my relay or 87 on a 4 post relay) and positive to the pump from relay post 30. Negative of pump is grounded to frame.
post 85 and 86 connect inside of relay through a coil that when energized connects OR disconnects 87 and 30
I needed a normally closed relay that when energized disconnects and here's why.
when no power to relay, 87 and 30 are connected ( that's OK because there is also no power feeding the pump because the key is not on )
With key on and engine is not running oil pressure light is on because sending unit is grounded and now relay is grounded (and energized ) and relay now disconnects 78 and 30 (the pump circuit.)
When engine runs and oil pressure light goes out it is because the sending unit losses ground. When relay losses ground 87 and 30 are connected and pump is powered. (Whew!)
I run a single carb and I dont think I will need the pump running to start my bike because there is a lot of fuel in the carb float bowl.
If it turns out I'm wrong I will put a switch in the ground wire going to oil sending unit to temp brake circuit and close relay before starting.
Why run like this through relay you say? Just a kinda safety feature so if the bike is not running the fuel stops flowing just like a manual pump.
Anyway, had to cobble up a bracket to mount pump and also block off opening where old pump was. Made that today and hope to finish mounting all tomorrow.
Here's some pics. flat black on the bracket and once I know the pump is not dead out of the box it will be flat black too. To match the rest of the bike. :smilie_happy: