ArdWrknTrk Posted July 25 Share Posted July 25 Only delay switches move left of center. Only delay switches have a ground wire.... 💡 That's a hot ticket but if information there. Look for a ground wire. Well, the plug is different and won't fit directly into the dash harness, only into a speed governor, and the speed governor will plug into the dash harness... Link to comment Share on other sites More sharing options...
Danny G Posted July 26 Share Posted July 26 Well, the plug is different and won't fit directly into the dash harness, only into a speed governor, and the speed governor will plug into the dash harness... I was setting up to start rewiring the games for the fuel pump control. I have everything laid out and marked ready to go but before I stripped that first wire it really kept bugging me that these are all 16awg wires protected with 20awg fuse links. I needed to know what the amount draw on the fuel pumps is and I'm getting mixed info from 4 amps to 10. 10 amp draw on 16 AWG for 20 feet to the back pump seems like it's pushing it. I would feel more comfortable running 10-12g for that. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted July 26 Share Posted July 26 I was setting up to start rewiring the games for the fuel pump control. I have everything laid out and marked ready to go but before I stripped that first wire it really kept bugging me that these are all 16awg wires protected with 20awg fuse links. I needed to know what the amount draw on the fuel pumps is and I'm getting mixed info from 4 amps to 10. 10 amp draw on 16 AWG for 20 feet to the back pump seems like it's pushing it. I would feel more comfortable running 10-12g for that. I don't think it's anything like 10A. Not that I have a pump in my hand to measure, nor do I know the value of the 'run' resistor. I mean , bigger wire can never hurt but the 20Ga. fuselink lasts forever unless there's a dead short I've never had to replace one.... Link to comment Share on other sites More sharing options...
viven44 Posted July 26 Share Posted July 26 I was setting up to start rewiring the games for the fuel pump control. I have everything laid out and marked ready to go but before I stripped that first wire it really kept bugging me that these are all 16awg wires protected with 20awg fuse links. I needed to know what the amount draw on the fuel pumps is and I'm getting mixed info from 4 amps to 10. 10 amp draw on 16 AWG for 20 feet to the back pump seems like it's pushing it. I would feel more comfortable running 10-12g for that. If this is the stock in-tank pump that feeds the carburetors, I measured them at <2A ... if things are running hot and wires are possibly undersized, I would have seen some signs of wire deterioration over 40 years.. but everything still looks brand new. I would go with the stock wire gauges. Maybe go up 1 size if you want margin. The resistor that is built in... the voltage drop would be proportional to the current draw so too much draw would limit voltage to the pumps.. This happened to me. I had a bad pump which was drawing over 4 amps before it would cut off (due to voltage drop.. i don't know?) ... Link to comment Share on other sites More sharing options...
Nothing Special Posted July 26 Share Posted July 26 .... And it may also seem like semantics.... I always get a kick out of "it's just semantics." Because often when people say that they are exactly right (although they don't know what they are saying). "Semantics" is defined as "the branch of linguistics and logic concerned with meaning", or "relating to meaning in language." Since the entire point of saying something to someone is to communicate meaning to them, "it's just semantics" is synonymous with "it's just the entire point!" Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 26 Author Share Posted July 26 .... And it may also seem like semantics.... I always get a kick out of "it's just semantics." Because often when people say that they are exactly right (although they don't know what they are saying). "Semantics" is defined as "the branch of linguistics and logic concerned with meaning", or "relating to meaning in language." Since the entire point of saying something to someone is to communicate meaning to them, "it's just semantics" is synonymous with "it's just the entire point!" Bob - That's just semantics. What I really meant is well described by How Stuff Works as "It's a way to be dismissive of language itself as carrier for ideas." Seriously though, you are right. Ford was very specific in their terminology and if you don't use their semantics you cannot find the part you are looking for - unless you luck onto someone else that also doesn't understand Ford's twisted logic and calls the part by the wrong name just like you. Link to comment Share on other sites More sharing options...
Danny G Posted July 26 Share Posted July 26 If this is the stock in-tank pump that feeds the carburetors, I measured them at Ok good that makes me feel better. I have a lot of GXL 16 AWG from our friends at AC DC supply and then some very short runs of 14AWG and 12 AWG silicone wire. The schematics do show a 0.75ohm PK/B H resistance wire on this run. That wire burned up. I'm unsure of why they added this resistance here other than to control basically power back feed to the relay when the ignition is in start since there was not a central power distribution box. If that's the case I'm kinda curious if using the diode fuse that Ford has in the later model PD boxes could work in lieu of the resistance wire. Because this would essentially do the same thing. Power applied to pump during start from one wire at the splice then power from the inertia switch side at all other times. Link to comment Share on other sites More sharing options...
Danny G Posted July 26 Share Posted July 26 If this is the stock in-tank pump that feeds the carburetors, I measured them at <2A ... if things are running hot and wires are possibly undersized, I would have seen some signs of wire deterioration over 40 years.. but everything still looks brand new. I would go with the stock wire gauges. Maybe go up 1 size if you want margin. The resistor that is built in... the voltage drop would be proportional to the current draw so too much draw would limit voltage to the pumps.. This happened to me. I had a bad pump which was drawing over 4 amps before it would cut off (due to voltage drop.. i don't know?) ... Ok good that makes me feel better. I have a lot of GXL 16 AWG from our friends at AC DC supply and then some very short runs of 14AWG and 12 AWG silicone wire. The schematics do show a 0.75ohm PK/B H resistance wire on this run. That wire burned up. I'm unsure of why they added this resistance here other than to control basically power back feed to the relay when the ignition is in start since there was not a central power distribution box. If that's the case I'm kinda curious if using the diode fuse that Ford has in the later model PD boxes could work in lieu of the resistance wire. Because this would essentially do the same thing. Power applied to pump during start from one wire at the splice then power from the inertia switch side at all other times. Did one better. I made a video using Volt Sim showing power flow. Â Link to comment Share on other sites More sharing options...
viven44 Posted July 26 Share Posted July 26 If this is the stock in-tank pump that feeds the carburetors, I measured them at <2A ... if things are running hot and wires are possibly undersized, I would have seen some signs of wire deterioration over 40 years.. but everything still looks brand new. I would go with the stock wire gauges. Maybe go up 1 size if you want margin. The resistor that is built in... the voltage drop would be proportional to the current draw so too much draw would limit voltage to the pumps.. This happened to me. I had a bad pump which was drawing over 4 amps before it would cut off (due to voltage drop.. i don't know?) ... Ok good that makes me feel better. I have a lot of GXL 16 AWG from our friends at AC DC supply and then some very short runs of 14AWG and 12 AWG silicone wire. The schematics do show a 0.75ohm PK/B H resistance wire on this run. That wire burned up. I'm unsure of why they added this resistance here other than to control basically power back feed to the relay when the ignition is in start since there was not a central power distribution box. If that's the case I'm kinda curious if using the diode fuse that Ford has in the later model PD boxes could work in lieu of the resistance wire. Because this would essentially do the same thing. Power applied to pump during start from one wire at the splice then power from the inertia switch side at all other times. Very nice demonstration using 'Volt Sim'.. I will need to understand more about that utility. As to the resistor's function, it is not preventing back-flow like a diode and in fact I don't believe that protection is necessary as the cut-off relay should be open while cranking... while cranking, the oil pressure switch shouldn't be closed, and it prevents the relay from closing. Even if that relay closed momentarily, you would have 12V at the 'node' before the resistor (past the inertial switch) and current wouldn't flow there as there isn't a potential difference. I believe the resistor is a current limiting device for sustained operation. A fuel pump's internal resistance can be pretty low and without that resistor the entire battery voltage would be applied to the pump and could cause the pump to burn up with sustained operation... if there was an internal short there is a current limiting safety necessary as well. This is similar to the requirement of a series resistor for an LED. Your resistor wire (or more likely the insulation on it) getting burnt up tells me the fuel pump was drawing too much current at some point.... Link to comment Share on other sites More sharing options...
Danny G Posted July 26 Share Posted July 26 Very nice demonstration using 'Volt Sim'.. I will need to understand more about that utility. As to the resistor's function, it is not preventing back-flow like a diode and in fact I don't believe that protection is necessary as the cut-off relay should be open while cranking... while cranking, the oil pressure switch shouldn't be closed, and it prevents the relay from closing. Even if that relay closed momentarily, you would have 12V at the 'node' before the resistor (past the inertial switch) and current wouldn't flow there as there isn't a potential difference. I believe the resistor is a current limiting device for sustained operation. A fuel pump's internal resistance can be pretty low and without that resistor the entire battery voltage would be applied to the pump and could cause the pump to burn up with sustained operation... if there was an internal short there is a current limiting safety necessary as well. This is similar to the requirement of a series resistor for an LED. Your resistor wire (or more likely the insulation on it) getting burnt up tells me the fuel pump was drawing too much current at some point.... Interesting. I have to figure that out about to drive to work. Ohms law 12VDC/.75 Ohms = 16 amp It's been a while. I think it may be geared on draw vs supply right? So if the pump pulls 3A then V=0.75Ohm x 3A Vd = 1.5VDC? My brain is still dang foggy from my accident. Link to comment Share on other sites More sharing options...
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