Fuel relay help
Discussion
I drove the car{s2} out of garage to warm up before going for a blast yesterday. After five minutes it cut out and would not restart. Cannot hear the fuel pump priming on ignition so i suspect possible relay-wiring problem. Gonna do the straight through wiring thing today to check pump works. The "bible" says it has a yellow relay, which i have found. It is a ford unit, four pins, 86,85,87,30. After reading a lot of old PH threads i think it shud have five pins. Have I found the wrong relay. Anyone help? I hate electrics
If it was working OK before I suggest you replace it with exactly the same type of relay. I don't know anything about the yelow relay, so it may be a standard relay or it may not. If it's a standard relay, the pin configuration is normally two pins for the coil, one power in, one power out.
Five pin relays are the same but with an extra power out terminal. The most common ones are usually change over relays where the relay switches the input between the two outputs. But you can also get dual output relays where the relay connects the input to both outputs when it is energised. On my V8, the fuel pump relay is a dual output relay (with the second output powering the lambda sensor heaters).
Relays also come in different current ratings. I would expect this to be a 40 Amp relay.
Five pin relays are the same but with an extra power out terminal. The most common ones are usually change over relays where the relay switches the input between the two outputs. But you can also get dual output relays where the relay connects the input to both outputs when it is energised. On my V8, the fuel pump relay is a dual output relay (with the second output powering the lambda sensor heaters).
Relays also come in different current ratings. I would expect this to be a 40 Amp relay.
keirangrogan said:
[quote=GreenV8S] On my V8, the fuel pump relay is a dual output relay (with the second output powering the lambda sensor heaters).[quote]
That would seem to suggest four pin relay for pre cat engines & 5 pin relay for engines with cats
You are right, four pins on pre cat engines. Seems the relay was stickin open so no fuel. I was trying to find power to the fuel pump, not realising it would not be there until the ecu gave it some through the relay once the engine starts. Wasnt workin on prime neither. Works fine now but gonna ordered a new one. 6 hours of fiddling, sun still shining so just had to go out and try it. {for two hours} 
Gassing Station | S Series | Top of Page | What's New | My Stuff