axe2011 Posted June 26, 2021 Author Share Posted June 26, 2021 That's great news! Yes, a vacuum leak could cause all sorts of problems. One way to find vacuum leaks is with the "smoke test" or, as David phrased it, Vacuum leak detection - effective and inexpensive. Well....when it rains it pours. I thought since I had ruled out the wiring harness in the injectors I should retape and wrap it. Got it all wrapped back up and put back on the truck and now I have a new issue. With the key turned on and engine off I can hear the fuel pump turn on but it never turns off. I immediately pulled the injector rail to see if it was spraying fuel back into the motor again, but that wasn't the issue. When I push the relief valve on the rail gas sprays out so its pressurized. I can hear a hissing noise while the pump is running, which I thought was spraying, but I can't find any leak anywhere. I tried replacing the relay and it still stays on constantly. Any ideas what I should check next? It has a new hp pump and fuel filter and the front tank is full. On a plus side after tearing though about 50 old F150/250s at a junk yard in Garber, Iowa I was able to find the coolant tree, and a couple of the other parts I needed. I also was able to source an fuel rail from Idaho which should be a match as well, its in the mail! Hopefully I can get these parts on and have some success. Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 27, 2021 Share Posted June 27, 2021 Well....when it rains it pours. I thought since I had ruled out the wiring harness in the injectors I should retape and wrap it. Got it all wrapped back up and put back on the truck and now I have a new issue. With the key turned on and engine off I can hear the fuel pump turn on but it never turns off. I immediately pulled the injector rail to see if it was spraying fuel back into the motor again, but that wasn't the issue. When I push the relief valve on the rail gas sprays out so its pressurized. I can hear a hissing noise while the pump is running, which I thought was spraying, but I can't find any leak anywhere. I tried replacing the relay and it still stays on constantly. Any ideas what I should check next? It has a new hp pump and fuel filter and the front tank is full. On a plus side after tearing though about 50 old F150/250s at a junk yard in Garber, Iowa I was able to find the coolant tree, and a couple of the other parts I needed. I also was able to source an fuel rail from Idaho which should be a match as well, its in the mail! Hopefully I can get these parts on and have some success. I think you have a ground on the Tan/Light Green wire. In the Page 60, below, you can see that power goes to the fuel pump relay via the Red wire at ZZ. Then on Page 103 it comes into the fuel pump relay and then goes out on the Tan/Light Green wire via YY. And on Page 62 it comes in to the computer, the ECA, on the T/LG wire. The ECA is supposed to ground the T/LG wire when you turn the key on, and I think it is supposed to take the ground away after a few seconds unless the engine starts. But if you have a ground on that wire the relay will stay engaged and the pump will continue to run. I would pull the relay to see that it does stop at that point. If so I'd find the ground, which may be in the self-test connector or its wiring. Link to comment Share on other sites More sharing options...
85lebaront2 Posted June 28, 2021 Share Posted June 28, 2021 Well....when it rains it pours. I thought since I had ruled out the wiring harness in the injectors I should retape and wrap it. Got it all wrapped back up and put back on the truck and now I have a new issue. With the key turned on and engine off I can hear the fuel pump turn on but it never turns off. I immediately pulled the injector rail to see if it was spraying fuel back into the motor again, but that wasn't the issue. When I push the relief valve on the rail gas sprays out so its pressurized. I can hear a hissing noise while the pump is running, which I thought was spraying, but I can't find any leak anywhere. I tried replacing the relay and it still stays on constantly. Any ideas what I should check next? It has a new hp pump and fuel filter and the front tank is full. On a plus side after tearing though about 50 old F150/250s at a junk yard in Garber, Iowa I was able to find the coolant tree, and a couple of the other parts I needed. I also was able to source an fuel rail from Idaho which should be a match as well, its in the mail! Hopefully I can get these parts on and have some success. The hissing noise is the fuel going through the pressure regulator and returning to the tank. Link to comment Share on other sites More sharing options...
axe2011 Posted June 28, 2021 Author Share Posted June 28, 2021 I think you have a ground on the Tan/Light Green wire. In the Page 60, below, you can see that power goes to the fuel pump relay via the Red wire at ZZ. Then on Page 103 it comes into the fuel pump relay and then goes out on the Tan/Light Green wire via YY. And on Page 62 it comes in to the computer, the ECA, on the T/LG wire. The ECA is supposed to ground the T/LG wire when you turn the key on, and I think it is supposed to take the ground away after a few seconds unless the engine starts. But if you have a ground on that wire the relay will stay engaged and the pump will continue to run. I would pull the relay to see that it does stop at that point. If so I'd find the ground, which may be in the self-test connector or its wiring. Thanks for your help Gary. I decided yesterday I was going to trace every wire from the EEC to its destination in order to ensure they actually go where they are supposed to. So far between the kids, wife, and chores I have made it to pin 22. I found today that Pin 17 and Pin 48 (shown on page 62 of the diagrams you provided) were actually flip flopped, not sure if this would have cause the issues, but it will probably help me if I ever want to pull codes in the future. Like I said earlier in this thread I believe someone replaced the harness as it has two splice points along it on either side of the motor. I am slowly winning the war on this truck. Is there a chart of what the Connections look like. I assume C171 is the grey connector right next to the C168 connector that in my truck is red and is right behind the battery. So far on this project I have learned how to use a test light, somewhat how to use multimeter, and how to solder, so if nothing else I am learning a lot fast! It will all be worth it when I can cruise around in the old girl. I will look tomorrow night If I can find any issues off the pin 22 on the EEC and try to follow it all through the fuel pump control diagram. Again thanks, I definitely would be lost without your help! Link to comment Share on other sites More sharing options...
axe2011 Posted June 28, 2021 Author Share Posted June 28, 2021 The hissing noise is the fuel going through the pressure regulator and returning to the tank. I thought that might be it too, I bought another regulator, but I couldn’t get the mangled fuel rail to seat again and not leak. So currently I have the old mangled rail off and another one in the mail From Idaho. Hopefully in a few days I’ll be able to put it all back together and finger crossed it was just that part! Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 28, 2021 Share Posted June 28, 2021 Thanks for your help Gary. I decided yesterday I was going to trace every wire from the EEC to its destination in order to ensure they actually go where they are supposed to. So far between the kids, wife, and chores I have made it to pin 22. I found today that Pin 17 and Pin 48 (shown on page 62 of the diagrams you provided) were actually flip flopped, not sure if this would have cause the issues, but it will probably help me if I ever want to pull codes in the future. Like I said earlier in this thread I believe someone replaced the harness as it has two splice points along it on either side of the motor. I am slowly winning the war on this truck. Is there a chart of what the Connections look like. I assume C171 is the grey connector right next to the C168 connector that in my truck is red and is right behind the battery. So far on this project I have learned how to use a test light, somewhat how to use multimeter, and how to solder, so if nothing else I am learning a lot fast! It will all be worth it when I can cruise around in the old girl. I will look tomorrow night If I can find any issues off the pin 22 on the EEC and try to follow it all through the fuel pump control diagram. Again thanks, I definitely would be lost without your help! I wouldn't think that having 17 and 48 reversed would cause a problem as long as nothing is plugged into the STI. But if there is something plugged in then it might cause problems. I'd fix it were I you. And there is a table at the back of each section of the EVTM. Here's the one from the section that includes most of what we've been talking about: Link to comment Share on other sites More sharing options...
axe2011 Posted June 30, 2021 Author Share Posted June 30, 2021 I wouldn't think that having 17 and 48 reversed would cause a problem as long as nothing is plugged into the STI. But if there is something plugged in then it might cause problems. I'd fix it were I you. And there is a table at the back of each section of the EVTM. Here's the one from the section that includes most of what we've been talking about: Do you know what a infrared mileage sensor is? There is a plug under the dash but nothing in it, should it have something or does it matter? Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 30, 2021 Share Posted June 30, 2021 Do you know what a infrared mileage sensor is? There is a plug under the dash but nothing in it, should it have something or does it matter? It is actually an "inferred" mileage system, and you can read about it at Documentation/Emissions/Inferred Mileage System. If the writeup is accurate then w/o that the ECA (computer) is going to think it is in a brand new vehicle and will probably give the engine a richer air/fuel ratio to account for an assumed tight engine. So when you get the truck going well and it seems like it is still running a bit rich, that might be the culprit. And it would seem that just placing power on the T/LG wire would solve the problem, but I don't know that for sure. Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 30, 2021 Share Posted June 30, 2021 It is actually an "inferred" mileage system, and you can read about it at Documentation/Emissions/Inferred Mileage System. If the writeup is accurate then w/o that the ECA (computer) is going to think it is in a brand new vehicle and will probably give the engine a richer air/fuel ratio to account for an assumed tight engine. So when you get the truck going well and it seems like it is still running a bit rich, that might be the culprit. And it would seem that just placing power on the T/LG wire would solve the problem, but I don't know that for sure. Actually, your system is slightly more complex than the one shown on the page referenced. You can see the inferred mileage system in the lower left of the schematic below: Link to comment Share on other sites More sharing options...
axe2011 Posted July 3, 2021 Author Share Posted July 3, 2021 Actually, your system is slightly more complex than the one shown on the page referenced. You can see the inferred mileage system in the lower left of the schematic below: Got it all back together and running again! Seems to be idling pretty high, but when I shift into a gear it drops in rpm to what seems more normal. Maybe a vacuum issue, not sure yet. Slow progress! Link to comment Share on other sites More sharing options...
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