vjsimone Posted May 19, 2018 Share Posted May 19, 2018 Vinny - Is that intermittent? He's had it happen and then go away. And, what causes it? Just a bad ECA? I have not seen it intermittent, but I don't know if folks in the past have noticed an intermittent period prior to a total failure. Other than a short to ground in the Fuel Relay circuit, the Fuel Relay is controlled by the ECA. EDIT; This ground wire also leads over to the OBDI test connector, so, if this wire shorts to ground, you would experience continuous running fuel pumps. I don't know what goes cattywampus in the ECA when this happens. I've seen in the past, that 99% of the run-on Fuel Pump scenarios were ECA related. There is a timing circuit that is triggered off the PIP signal, if the circuit does not see a PIP within a second, the ground is removed from the Fuel Relay. This is why when the key is turned to ON, the fuel pumps only run for a second. So, it is possible that the electronic device (FET?) that provides the ground is failing, or the circuit that controls this device is failing. (Best guess). So, I could see where the circuit controling the grounding component could fail and keep the device in ground path mode. I'm guessing when this occurred, he probably had no spark as well. Link to comment Share on other sites More sharing options...
vjsimone Posted May 19, 2018 Share Posted May 19, 2018 “I can hear the fuel pump come on, but it is running continuously and not building enough pressure to shut off like it normally does before I start the truck.” For clarification, there is no “shut off” when the pressure reaches the maximum capability of the High-Pressure Fuel Pump. As designed, as long as the engine is running the fuel pumps will run. Fuel pressure control is designed into the Fuel Pressure Regulator. “I let it run and checked for fuel at the schrader valve on the fuel rail, and I have fuel, it just doesn't seem to be building enough pressure and isn't firing.” Fuel Pressure readings are only a guess without using a pressure gauge. Link to comment Share on other sites More sharing options...
vjsimone Posted May 19, 2018 Share Posted May 19, 2018 Was it raining when this occurred ? Link to comment Share on other sites More sharing options...
fords4life Posted May 19, 2018 Author Share Posted May 19, 2018 Was it raining when this occurred ? It had rained pretty hard that night. What do PIP and FET stand for? I did not have time to confirm if I had spark or not unfortunately, so who knows. Completely agreed on the fuel pressure, I only know that I had fuel flowing through the rail, no idea on how much pressure or volume was moving. Thank you for the clarification on the fuel pump shutoff being timing instead of pressure based. I had apparently read some misinformation elsewhere as to what caused them to shutoff. Link to comment Share on other sites More sharing options...
vjsimone Posted May 19, 2018 Share Posted May 19, 2018 It had rained pretty hard that night. What do PIP and FET stand for? I did not have time to confirm if I had spark or not unfortunately, so who knows. Completely agreed on the fuel pressure, I only know that I had fuel flowing through the rail, no idea on how much pressure or volume was moving. Thank you for the clarification on the fuel pump shutoff being timing instead of pressure based. I had apparently read some misinformation elsewhere as to what caused them to shutoff. FET, is Field Effect Transistor, but I don’t know if that is what the 3-legged components are in the ECA providing the grounds. There is some technology of Driver/Transistor or electronic switch in the ECA heatsinked around the edges, but I have not read the numbers off the devices to date. The PIP is the pulse output from the Hall-Effect device in the Dizzy. As the Dizzy shaft spins, the slotted metal yoke attached to the shaft makes and brakes the magnetic field to the Hall-Device. That PIP pulse is channeled thu the TFI/Ignition Module to the ECA. As long as everything is working as designed, when the Dizzy is spinning, you have a Pulse. This is why the fuel pressure relay does not energize longer than 1 second when the engine is not running, and key is turned to on. No pulse, timer circuit allows a 1 second relay turn on until the circuit sees another PIP pulse. As long as the frequency of PIP pulses is greater than 1 pulse per second, fuel pumps run continuously. The PIP also excites the SpOut circuit which may adjust the Timing circuit provided by the TFI/IM to switch the Coil On/Off, and provide the signal to a tachometer if installed. Link to comment Share on other sites More sharing options...
vjsimone Posted May 19, 2018 Share Posted May 19, 2018 It had rained pretty hard that night. What do PIP and FET stand for? I did not have time to confirm if I had spark or not unfortunately, so who knows. Completely agreed on the fuel pressure, I only know that I had fuel flowing through the rail, no idea on how much pressure or volume was moving. Thank you for the clarification on the fuel pump shutoff being timing instead of pressure based. I had apparently read some misinformation elsewhere as to what caused them to shutoff. We have seen a few folks that only had the pump run-on issue when it was raining, maybe high humidity/dewpoint….. One guy replaced his ECA with 2 new ECAs, both had this run-on when it rained, he purchased a used JY dog ECA, and this solved his problem. I believe one of the other guys had water running in under his dash and into the ECA. Link to comment Share on other sites More sharing options...
sgauvry Posted May 21, 2018 Share Posted May 21, 2018 We have seen a few folks that only had the pump run-on issue when it was raining, maybe high humidity/dewpoint….. One guy replaced his ECA with 2 new ECAs, both had this run-on when it rained, he purchased a used JY dog ECA, and this solved his problem. I believe one of the other guys had water running in under his dash and into the ECA. Vinny is correct with regard to this because that guy was me. With cold starts it started right up. Once the engine was hot, it would not start. If I let it cool, it started right up. From what I read, seems that may be your case also. Link to comment Share on other sites More sharing options...
fords4life Posted July 18, 2018 Author Share Posted July 18, 2018 Vinny is correct with regard to this because that guy was me. With cold starts it started right up. Once the engine was hot, it would not start. If I let it cool, it started right up. From what I read, seems that may be your case also. So....this problem has come and gone twice, and now is here to stay. It's been 2 days since the last rain and still no start this morning. With the previous lighting issues I had that mysteriously went away, I'm guessing I have a ground problem somewhere, but wondering if anyone has any advice on where to start? My other truck decided it didn't want to start so I'm kind of SOL on trucks and I think the '86 will be easier to get going so I'm planning on attacking it tonight. 1. Everything under the dash around the ECA looks clean/no water. I have not removed the ECA yet. 2. I need to verify that I have spark while cranking. 3. I will review the EVTM and can start their, but I know some of those procedures are designed around a breakout box which I don't have. Thoughts on things to check without just throwing parts at it. TIA Nathan Link to comment Share on other sites More sharing options...
Gary Lewis Posted July 18, 2018 Share Posted July 18, 2018 So....this problem has come and gone twice, and now is here to stay. It's been 2 days since the last rain and still no start this morning. With the previous lighting issues I had that mysteriously went away, I'm guessing I have a ground problem somewhere, but wondering if anyone has any advice on where to start? My other truck decided it didn't want to start so I'm kind of SOL on trucks and I think the '86 will be easier to get going so I'm planning on attacking it tonight. 1. Everything under the dash around the ECA looks clean/no water. I have not removed the ECA yet. 2. I need to verify that I have spark while cranking. 3. I will review the EVTM and can start their, but I know some of those procedures are designed around a breakout box which I don't have. Thoughts on things to check without just throwing parts at it. TIA Nathan You are on the right track by checking for spark. But if you have it you should then check for fuel pressure. By '86 I think the EFI system had a Schrader valve which you can depress to see if you do have pressure. If not, then you need to see if the fuel pumps are running. As for grounds, Page 10 of the 1986 EVTM shows a special ground for those trucks with the ECA. (My version has it called out.) You might check that. Link to comment Share on other sites More sharing options...
fords4life Posted July 18, 2018 Author Share Posted July 18, 2018 You are on the right track by checking for spark. But if you have it you should then check for fuel pressure. By '86 I think the EFI system had a Schrader valve which you can depress to see if you do have pressure. If not, then you need to see if the fuel pumps are running. As for grounds, Page 10 of the 1986 EVTM shows a special ground for those trucks with the ECA. (My version has it called out.) You might check that. I need to see if I can find a gauge locally to go onto the fuel rail schrader valve, but the last time it happened, I had pressure, just not sure how much. That and the sound of the fuel pumps running lead me to believe the issue is ignition/computer related, not fuel system related. Link to comment Share on other sites More sharing options...
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