SoCalManche Posted April 22, 2019 Author Share Posted April 22, 2019 1 minute ago, Jeep Driver said: I suspect he's got a problem with all his grounds. Could the dipstick stud grounds be causing these issues? That is an overly important grounding spot, correct? Link to comment Share on other sites More sharing options...
Ωhm Posted April 22, 2019 Share Posted April 22, 2019 10 hours ago, SoCalManche said: As far as how I've measured it, the ignition is OFF, I disconnect the two three-pin connectors, one coming from the truck cab, and the other being the fuel pump itself. Once the fuel pump is disconnected, I take the other connector and back-probe the middle pin, and ground out to the chassis. That's how I get 40 ohms. Sounds like this ohms measurement is through the fuel gauge in the cluster (C139_B). Reading could be normal for measurement taken. Link to comment Share on other sites More sharing options...
SoCalManche Posted April 22, 2019 Author Share Posted April 22, 2019 Is there anyway someone can provide me assistance on what to look for as far as problems are concerned? If that's the correct ohms reading,then how to I measure to see what's incorrect? Link to comment Share on other sites More sharing options...
Ωhm Posted April 22, 2019 Share Posted April 22, 2019 Does the starter engage and turn the engine over when the IGN SW is in the CRANK position? Link to comment Share on other sites More sharing options...
SoCalManche Posted April 22, 2019 Author Share Posted April 22, 2019 Just now, Ωhm said: Does the starter engage and turn the engine over when the IGN SW is in the CRANK position? Yes, if fuel is put in the throttle body. Link to comment Share on other sites More sharing options...
Ωhm Posted April 22, 2019 Share Posted April 22, 2019 3 minutes ago, SoCalManche said: if fuel is put in the throttle body. So engine will START and RUN when fuel is added until added fuel is gone? Link to comment Share on other sites More sharing options...
SoCalManche Posted April 22, 2019 Author Share Posted April 22, 2019 Just now, Ωhm said: So engine will START and RUN when fuel is added until added fuel is gone? Correct. Starts up easily, and dies once fuel is burned off from TBI. Link to comment Share on other sites More sharing options...
Ωhm Posted April 22, 2019 Share Posted April 22, 2019 Need to take some voltage measurements. Use the following connectors callout. D1 and D2 are located under the hood, right side of engine compartment. Should have yellow covers on them. D1_5 Battery Voltage (B+) Hot at all times. D1_2 Battery Voltage (B+) Hot with KEY in RUN or CRANK position. D1_6 Battery Voltage (B+) Hot with KEY in RUN position (only 2-3 seconds). This ones tricky, because of time limited. Hope you can do these voltage measurements by yourself. Forgot to mention, use battery negative terminal as DVOM ground. Link to comment Share on other sites More sharing options...
SoCalManche Posted April 22, 2019 Author Share Posted April 22, 2019 17 minutes ago, Ωhm said: Need to take some voltage measurements. Use the following connectors callout. D1 and D2 are located under the hood, right side of engine compartment. Should have yellow covers on them. D1_5 Battery Voltage (B+) Hot at all times. D1_2 Battery Voltage (B+) Hot with KEY in RUN or CRANK position. D1_6 Battery Voltage (B+) Hot with KEY in RUN position (only 2-3 seconds). This ones tricky, because of time limited. Hope you can do these voltage measurements by yourself. Forgot to mention, use battery negative terminal as DVOM ground. D1_5: 12.5 volts D1_2: 10.6-10.7 volts D1_6: 1.8 volts Link to comment Share on other sites More sharing options...
Ωhm Posted April 22, 2019 Share Posted April 22, 2019 Remove Fuel Pump Relay and using a fused jumper wire, connect C216_1(30) to C216_4(87) at the fuel pump relay block. Retake voltage measurement at D1_6 again. Link to comment Share on other sites More sharing options...
Ωhm Posted April 22, 2019 Share Posted April 22, 2019 Link to comment Share on other sites More sharing options...
Ωhm Posted April 22, 2019 Share Posted April 22, 2019 Also with fused jumper in place, fuel pump should be running (pumping). Link to comment Share on other sites More sharing options...
SoCalManche Posted April 22, 2019 Author Share Posted April 22, 2019 16 minutes ago, Ωhm said: Also with fused jumper in place, fuel pump should be running (pumping). Gotcha. I have to run and grab a jumper. Link to comment Share on other sites More sharing options...
SoCalManche Posted April 22, 2019 Author Share Posted April 22, 2019 1 hour ago, Ωhm said: Also with fused jumper in place, fuel pump should be running (pumping). Does it matter what size fuse to put in the jump wire? Link to comment Share on other sites More sharing options...
Ωhm Posted April 22, 2019 Share Posted April 22, 2019 1 hour ago, SoCalManche said: Does it matter what size fuse to put in the jump wire? If you have a choice, start with 15A fuse. Link to comment Share on other sites More sharing options...
SoCalManche Posted April 22, 2019 Author Share Posted April 22, 2019 14 minutes ago, Ωhm said: If you have a choice, start with 15A fuse. That worked to engage fuel pump via 15A fused jumper wire. Too much fuel entered the intake, so waiting a few minutes before trying to start again. Will come back with reading. What does this mean for now? Link to comment Share on other sites More sharing options...
Ωhm Posted April 22, 2019 Share Posted April 22, 2019 Fused jumper wire is doing what the Fuel Pump Relay should do. Suspect Fuel Pump Relay. You said you've try a few different relay, but that jumper wire is doing the same thing. Hope engine starts. Link to comment Share on other sites More sharing options...
SoCalManche Posted April 22, 2019 Author Share Posted April 22, 2019 13 minutes ago, Ωhm said: Fused jumper wire is doing what the Fuel Pump Relay should do. Suspect Fuel Pump Relay. You said you've try a few different relay, but that jumper wire is doing the same thing. Hope engine starts. Would there be a reason as to why the original relay clicks repeatedly when a new relay won't? Link to comment Share on other sites More sharing options...
Ωhm Posted April 22, 2019 Share Posted April 22, 2019 Relays can fail in many different ways. Clicking means the relay coil can't hold the switching contact down on the other terminal. Does engine start with a new fuel pump relay installed? Link to comment Share on other sites More sharing options...
SoCalManche Posted April 22, 2019 Author Share Posted April 22, 2019 1 hour ago, Ωhm said: Relays can fail in many different ways. Clicking means the relay coil can't hold the switching contact down on the other terminal. Does engine start with a new fuel pump relay installed? No. With jumper wire connected, fuel pump constantly primes but no start. With original relay connected, no priming but will start with fuel added to TBI. Help...lol... Link to comment Share on other sites More sharing options...
Ωhm Posted April 22, 2019 Share Posted April 22, 2019 Does engine start with jumper and adding fuel to TBI? Link to comment Share on other sites More sharing options...
SoCalManche Posted April 22, 2019 Author Share Posted April 22, 2019 Also, now when I try to start with the original relay connected, the engine struggles to start with fuel added to TBI, and when it does, a popping noise occurs around the intake/TBI and it shuts off abruptly. Link to comment Share on other sites More sharing options...
SoCalManche Posted April 22, 2019 Author Share Posted April 22, 2019 Just now, Ωhm said: Does engine start with jumper and adding fuel to TBI? No, it didn't. Link to comment Share on other sites More sharing options...
Jeep Driver Posted April 22, 2019 Share Posted April 22, 2019 OK, well clearly it's not moving any fuel. Has it occurred to anyone that you have a bad pump???? It maybe that the pump has gone to ground and therefore the relay stammers. Time for a pump.......and go through ALL your grounds and cables and fused links...........ect......... Link to comment Share on other sites More sharing options...
SoCalManche Posted April 22, 2019 Author Share Posted April 22, 2019 2 minutes ago, Jeep Driver said: OK, well clearly it's not moving any fuel. Has it occurred to anyone that you have a bad pump???? It maybe that the pump has gone to ground and therefore the relay stammers. Time for a pump.......and go through ALL your grounds and cables and fused links...........ect......... I got a new pump orginally, which by the way isn't properly spec'd out for these trucks. But regardless, I took the original pump out, tested it at the battery, and it immediately started. Whenever I connect the jumper wire in the fuel pump relay, it immediate comes on. And it is definitely pushing fuel, because one of my fuel line retainer clips broke, and the new ones you buy need o-rings. I didn't know that, and so as soon as the jumper wire engaged between 30 and 87, fuel started coming out of the fuel lines at the connectors underneath the intake. Link to comment Share on other sites More sharing options...
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