old55pete Posted October 24, 2021 Share Posted October 24, 2021 Been pouring over the EVTM's trying to figure out a problem with the fuel pump relay not energising and firing up the fuel pumps. What I am finding is that with the key on, I have three hots. One from the ECM( control power), one from the battrie ( controlled power ) and another one on pin 22 which is supposed to be a feed back to the ECM. I can jumper the controlled power and get the pumps to fire up. I am hoping that some one can correct me, but I thought that pin 22 was supposed to be a ground to pull in the relay and and put voltage through the relay to fire up the pumps. Link to comment Share on other sites More sharing options...
85lebaront2 Posted October 24, 2021 Share Posted October 24, 2021 The way Ford set the system up, pin 22 is grounded upon initial key on, this is what gives you the short pump run when the key is turned on. When the EEC receives a crank signal (ignition pulse) it will turn the pump on to feed fuel to the cylinders. Question, is the EEC power relay energizing? Without that none of it will work, circuit 361, red wire, is the feed from the EEC power relay to the system, pump control, ignition, injectors and all the solenoids. A very common problem on these is the system ground connector, C101, it is a 1/4" spade connector near the battery negative post and is very prone to corrosion. A bad ground will kill the system as far as running. Link to comment Share on other sites More sharing options...
old55pete Posted October 24, 2021 Author Share Posted October 24, 2021 The way Ford set the system up, pin 22 is grounded upon initial key on, this is what gives you the short pump run when the key is turned on. When the EEC receives a crank signal (ignition pulse) it will turn the pump on to feed fuel to the cylinders. Question, is the EEC power relay energizing? Without that none of it will work, circuit 361, red wire, is the feed from the EEC power relay to the system, pump control, ignition, injectors and all the solenoids. A very common problem on these is the system ground connector, C101, it is a 1/4" spade connector near the battery negative post and is very prone to corrosion. A bad ground will kill the system as far as running. Bill, I have checked that ground as I noted that it was a part of that system also. I am thinking that I will replace it to know for fact that it is good. The thing I have going on is that it stays powered. So if I jumper it and get the pumps going, even through the start and run, it still stays a 12 volt. If I understand correctly, before you start it it is a momentry ground to get fuel pressure to start, when it is running it is supposed to be a ground after it gets oil pressure, yet it still has a 12 volt feed back. What am I missing here? Link to comment Share on other sites More sharing options...
old55pete Posted October 24, 2021 Author Share Posted October 24, 2021 The way Ford set the system up, pin 22 is grounded upon initial key on, this is what gives you the short pump run when the key is turned on. When the EEC receives a crank signal (ignition pulse) it will turn the pump on to feed fuel to the cylinders. Question, is the EEC power relay energizing? Without that none of it will work, circuit 361, red wire, is the feed from the EEC power relay to the system, pump control, ignition, injectors and all the solenoids. A very common problem on these is the system ground connector, C101, it is a 1/4" spade connector near the battery negative post and is very prone to corrosion. A bad ground will kill the system as far as running. I just cut out the plug on ground 101 by the battery and soldered the connection. I still have the same result. Link to comment Share on other sites More sharing options...
old55pete Posted October 24, 2021 Author Share Posted October 24, 2021 The way Ford set the system up, pin 22 is grounded upon initial key on, this is what gives you the short pump run when the key is turned on. When the EEC receives a crank signal (ignition pulse) it will turn the pump on to feed fuel to the cylinders. Question, is the EEC power relay energizing? Without that none of it will work, circuit 361, red wire, is the feed from the EEC power relay to the system, pump control, ignition, injectors and all the solenoids. A very common problem on these is the system ground connector, C101, it is a 1/4" spade connector near the battery negative post and is very prone to corrosion. A bad ground will kill the system as far as running. So, what would happen if I just cut out the old relay and put an equeal sized one from say NAPA and omited the return from the ECM pin 22 and made that wire a ground? That way I still have the control power from the ECM to turn on the relay with the key Link to comment Share on other sites More sharing options...
85lebaront2 Posted October 24, 2021 Share Posted October 24, 2021 So, what would happen if I just cut out the old relay and put an equeal sized one from say NAPA and omited the return from the ECM pin 22 and made that wire a ground? That way I still have the control power from the ECM to turn on the relay with the key The reason it is done so the EEC controls it is safety, If the pumps run continuously and there is any problem they can empty the tank onto the ground, all over a hot engine or any of a number of scenarios. FWIW, Ford and Chrysler both use the computer to turn on the fuel pump, both do the short "burst" at key on by grounding the relay coil. Chrysler's is called an Automatic Shut Down relay and it is wired into the EFI feed like the Ford Power Relay so it powers fuel pump, coil and injectors along with the O2 sensor heater. GM uses (at least the ones I have worked on) an oil pressure switch to control the fuel pump relay. I would find out why it isn't working correctly, could be a sign the EEC is on it's way out. Link to comment Share on other sites More sharing options...
old55pete Posted November 6, 2021 Author Share Posted November 6, 2021 So, what would happen if I just cut out the old relay and put an equeal sized one from say NAPA and omited the return from the ECM pin 22 and made that wire a ground? That way I still have the control power from the ECM to turn on the relay with the key I finally figured it out, the wires are shorted in the relay plug. I replaced the plug with one from NAPA and wired it correctly from the EVTM and now it works like it should. Fuel pumps come on for a few seconds then shuts off, start it and the fuel pumps run like they are supposed to. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 6, 2021 Share Posted November 6, 2021 I finally figured it out, the wires are shorted in the relay plug. I replaced the plug with one from NAPA and wired it correctly from the EVTM and now it works like it should. Fuel pumps come on for a few seconds then shuts off, start it and the fuel pumps run like they are supposed to. Yippee!! Well done! Link to comment Share on other sites More sharing options...
old55pete Posted November 6, 2021 Author Share Posted November 6, 2021 Yippee!! Well done! And the plot thickins, it has now burnt up the new relay. I put in a relay test switch and powered the pumps, I could hear the pump in the tank come on but not the high pressure pump on the frame. Crawled under it and touched the hot wire in the pump and it was smoking hot. That pump was put in in may. I have a new one ordered from NAPA as that is where I got this one. Link to comment Share on other sites More sharing options...
Gary Lewis Posted November 6, 2021 Share Posted November 6, 2021 And the plot thickins, it has now burnt up the new relay. I put in a relay test switch and powered the pumps, I could hear the pump in the tank come on but not the high pressure pump on the frame. Crawled under it and touched the hot wire in the pump and it was smoking hot. That pump was put in in may. I have a new one ordered from NAPA as that is where I got this one. Yipes! The pump works, but is pulling way too much current? That sounds like a serious problem. Have you checked to make sure that no one has bypassed the resistance in the pump circuit? I don't think that, by itself, would account for the hot wire. But it wouldn't help. (Sure seems strange that the Bronco has the resistor but the F-Series doesn't. Wonder why?) Link to comment Share on other sites More sharing options...
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