Fuel Pump Relay question
Fuel Pump Relay question
12-08-11, 02:17 PM
#2
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You could probably get one used in the 2nd Generation Rx-7 (1986-1992) Parts section.
Or...
You could rewire your fuel pump, as you should have already done... and bypass the fuel pump relay & resistor. That may be a cheaper solution, while safely delivering the proper amount of voltage to the pump. There are PLENTY of different threads here on the forum, with great diagrams showing how to do this.
Or...
You could rewire your fuel pump, as you should have already done... and bypass the fuel pump relay & resistor. That may be a cheaper solution, while safely delivering the proper amount of voltage to the pump. There are PLENTY of different threads here on the forum, with great diagrams showing how to do this.
12-08-11, 02:52 PM
#3
You could probably get one used in the 2nd Generation Rx-7 (1986-1992) Parts section.
Or...
You could rewire your fuel pump, as you should have already done... and bypass the fuel pump relay & resistor. That may be a cheaper solution, while safely delivering the proper amount of voltage to the pump. There are PLENTY of different threads here on the forum, with great diagrams showing how to do this.
Or...
You could rewire your fuel pump, as you should have already done... and bypass the fuel pump relay & resistor. That may be a cheaper solution, while safely delivering the proper amount of voltage to the pump. There are PLENTY of different threads here on the forum, with great diagrams showing how to do this.
12-08-11, 07:41 PM
#5
Rotary Freak
Thread owner.......................are you referring to the relay up front near the radiator or are you referring to the one just above the drivers knees/steering column (the circuit opening relay)?
12-09-11, 10:47 AM
#7
Rotary Freak
That one is a little peculiar. It has two coils in it either of which can pull the relay in and pass power to the fuel pump (after it passes it to the fuel pump resistor relay up front first).
One of those two is operated anytime the key is put to START. Doing that pulls the relay in and passes power to the fuel pump. THAT coil has a gnd on it 24/7 and going to START puts power on that coil to make it pull in.
The other of the two coils in the relay is controlled by a micro switch in the afm. THAT coil has power on it anytime the key is put to ON. If the car starts the vane in the afm moves aft and "makes" the micro swtich who in turn puts a ground on one of the two coils in the circuit opening relay causing the relay to pull in and pass power to the fuel pump.
Talking series four car, not series five. Five is slightly different.
Anyway that circuit opening relay on a series four car, when pulled in, passes power to the fuel pump resistor relay up near the front right headlight on a turbo car which in turn passes the power on to the fuel pump to make the pump run.
Kinda saying in a roundabout way that to replace that relay you would need a aftermarket relay with two coils to make it work as stock. IF you decided to bypass the safety feature of that relay you could use a common automobile relay from ??? radio shack or such and ignore the wires to it that come from the afm's micro switch.
I guess you have checked and made sure that your relay is shot? Fuel pump on a series four car only pass power to the fuel pump IF the key is HELD to START or if the afm's vane is moved aft approx 1/8' or more. Either of those two conditions will make the pump run.
Key NOT held to START and the afm's vane not pulled aft will not make the pump run even if the key is put to just ON. That is IF the cars wiing is purely stk and not been messed with.
One of those two is operated anytime the key is put to START. Doing that pulls the relay in and passes power to the fuel pump. THAT coil has a gnd on it 24/7 and going to START puts power on that coil to make it pull in.
The other of the two coils in the relay is controlled by a micro switch in the afm. THAT coil has power on it anytime the key is put to ON. If the car starts the vane in the afm moves aft and "makes" the micro swtich who in turn puts a ground on one of the two coils in the circuit opening relay causing the relay to pull in and pass power to the fuel pump.
Talking series four car, not series five. Five is slightly different.
Anyway that circuit opening relay on a series four car, when pulled in, passes power to the fuel pump resistor relay up near the front right headlight on a turbo car which in turn passes the power on to the fuel pump to make the pump run.
Kinda saying in a roundabout way that to replace that relay you would need a aftermarket relay with two coils to make it work as stock. IF you decided to bypass the safety feature of that relay you could use a common automobile relay from ??? radio shack or such and ignore the wires to it that come from the afm's micro switch.
I guess you have checked and made sure that your relay is shot? Fuel pump on a series four car only pass power to the fuel pump IF the key is HELD to START or if the afm's vane is moved aft approx 1/8' or more. Either of those two conditions will make the pump run.
Key NOT held to START and the afm's vane not pulled aft will not make the pump run even if the key is put to just ON. That is IF the cars wiing is purely stk and not been messed with.
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12-09-11, 11:02 AM
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Ah, this is another "I think my fuel pump relay & resistor is my circuit opening relay"... threads. Considering his sig says '88 RX7 TII, I thought he was actually referring to the fuel pump relay & resistor.
freq, you're talking about two different things...
freq, you're talking about two different things...
12-09-11, 04:13 PM
#10
That one is a little peculiar. It has two coils in it either of which can pull the relay in and pass power to the fuel pump (after it passes it to the fuel pump resistor relay up front first).
One of those two is operated anytime the key is put to START. Doing that pulls the relay in and passes power to the fuel pump. THAT coil has a gnd on it 24/7 and going to START puts power on that coil to make it pull in.
The other of the two coils in the relay is controlled by a micro switch in the afm. THAT coil has power on it anytime the key is put to ON. If the car starts the vane in the afm moves aft and "makes" the micro swtich who in turn puts a ground on one of the two coils in the circuit opening relay causing the relay to pull in and pass power to the fuel pump.
Talking series four car, not series five. Five is slightly different.
Anyway that circuit opening relay on a series four car, when pulled in, passes power to the fuel pump resistor relay up near the front right headlight on a turbo car which in turn passes the power on to the fuel pump to make the pump run.
Kinda saying in a roundabout way that to replace that relay you would need a aftermarket relay with two coils to make it work as stock. IF you decided to bypass the safety feature of that relay you could use a common automobile relay from ??? radio shack or such and ignore the wires to it that come from the afm's micro switch.
I guess you have checked and made sure that your relay is shot? Fuel pump on a series four car only pass power to the fuel pump IF the key is HELD to START or if the afm's vane is moved aft approx 1/8' or more. Either of those two conditions will make the pump run.
Key NOT held to START and the afm's vane not pulled aft will not make the pump run even if the key is put to just ON. That is IF the cars wiing is purely stk and not been messed with.
One of those two is operated anytime the key is put to START. Doing that pulls the relay in and passes power to the fuel pump. THAT coil has a gnd on it 24/7 and going to START puts power on that coil to make it pull in.
The other of the two coils in the relay is controlled by a micro switch in the afm. THAT coil has power on it anytime the key is put to ON. If the car starts the vane in the afm moves aft and "makes" the micro swtich who in turn puts a ground on one of the two coils in the circuit opening relay causing the relay to pull in and pass power to the fuel pump.
Talking series four car, not series five. Five is slightly different.
Anyway that circuit opening relay on a series four car, when pulled in, passes power to the fuel pump resistor relay up near the front right headlight on a turbo car which in turn passes the power on to the fuel pump to make the pump run.
Kinda saying in a roundabout way that to replace that relay you would need a aftermarket relay with two coils to make it work as stock. IF you decided to bypass the safety feature of that relay you could use a common automobile relay from ??? radio shack or such and ignore the wires to it that come from the afm's micro switch.
I guess you have checked and made sure that your relay is shot? Fuel pump on a series four car only pass power to the fuel pump IF the key is HELD to START or if the afm's vane is moved aft approx 1/8' or more. Either of those two conditions will make the pump run.
Key NOT held to START and the afm's vane not pulled aft will not make the pump run even if the key is put to just ON. That is IF the cars wiing is purely stk and not been messed with.
12-09-11, 04:50 PM
#11
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I'm not at all calling you ignorant... This is all too common of a problem. If anything, it is the ignorance of your mechanic that I am pointing out. Although he doesn't see very many FC's, you'd think he could at least point you in the right direction when it came to relays. Luckily, you came here.
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2nd Generation Specific (1986-1992)
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