sgauvry Posted April 9, 2018 Share Posted April 9, 2018 Gents - Am working hard to get my new engine to start. Sounds like it wants to kick over but won't. Used ether and it starts for a moment and then cuts out. Did the same process over and over again with the same results. I am definitely getting fuel to the rail. I also checked to see if I am getting volts to the injector harness and it appears I am. Pulled one of the injectors out of its hole in the intake and cranked the engine to see if I would have fuel come out of it. I did not. Also pulled the number 4 plug (easiest for me to get to) and it was dry and has zero fuel smell to it. Ideas? Link to comment Share on other sites More sharing options...
Gary Lewis Posted April 9, 2018 Share Posted April 9, 2018 That's confusing - both fuel and power to the injectors but no fuel from the injectors? As shown on pages 60 & 61, the injectors are powered by the EEC power relay. But them just having power doesn't mean they are being used. The EEC has to ground them to cause current to flow and the injector to open. So you need to check the tan and tan/white wires that go from the injectors to the EEC to find out if the EEC is grounding them. You should see voltage readings going crazy as the injectors are grounded and then the ground is removed. If not, you need to figure out why the EEC isn't playing along. Link to comment Share on other sites More sharing options...
85lebaront2 Posted April 9, 2018 Share Posted April 9, 2018 That's confusing - both fuel and power to the injectors but no fuel from the injectors? As shown on pages 60 & 61, the injectors are powered by the EEC power relay. But them just having power doesn't mean they are being used. The EEC has to ground them to cause current to flow and the injector to open. So you need to check the tan and tan/white wires that go from the injectors to the EEC to find out if the EEC is grounding them. You should see voltage readings going crazy as the injectors are grounded and then the ground is removed. If not, you need to figure out why the EEC isn't playing along. Just in case, I think I still have at least one of the 1985.5/86 EECs I scrounged up when Matt was fighting with his. Be sure circuit 349 is connected to pin #56 and is seeing a pulse. That is the PIP (Profile Ignition Pickup) which tells the EEC the engine is turning and after it receives the #1 pulse (short pulse) starts firing the injectors. Link to comment Share on other sites More sharing options...
sgauvry Posted April 9, 2018 Author Share Posted April 9, 2018 That's confusing - both fuel and power to the injectors but no fuel from the injectors? As shown on pages 60 & 61, the injectors are powered by the EEC power relay. But them just having power doesn't mean they are being used. The EEC has to ground them to cause current to flow and the injector to open. So you need to check the tan and tan/white wires that go from the injectors to the EEC to find out if the EEC is grounding them. You should see voltage readings going crazy as the injectors are grounded and then the ground is removed. If not, you need to figure out why the EEC isn't playing along. So, voltmeter positive lead to the positive battery terminal, and negative lead to the tan wire? Link to comment Share on other sites More sharing options...
Gary Lewis Posted April 9, 2018 Share Posted April 9, 2018 So, voltmeter positive lead to the positive battery terminal, and negative lead to the tan wire? That would work. Or use a test light. Link to comment Share on other sites More sharing options...
sgauvry Posted April 9, 2018 Author Share Posted April 9, 2018 That would work. Or use a test light. Yes. There are two tan wires on the connector that go to the injectors. I am assuming I can use those to check. When probing those, I get very erratic numbers while cranking the engine. Link to comment Share on other sites More sharing options...
Gary Lewis Posted April 9, 2018 Share Posted April 9, 2018 Yes. There are two tan wires on the connector that go to the injectors. I am assuming I can use those to check. When probing those, I get very erratic numbers while cranking the engine. Each injector should have two wires - a red for power and either a tan or a tan/white that goes to the EEC and is grounded by it. Red should be the same as battery power when the key is on - within a few tenths of a volt. And the tan or tan/white wires should go from battery voltage to almost ground (.7v) and back very quickly. The rapid changes will confuse your DVM, which is why a test light is better - it'll flash. Anyway, if you are seeing the voltage go all over the map then it looks as if the computer is telling the injector to fire. So, if you don't have gas then you must have low/no fuel pressure. Link to comment Share on other sites More sharing options...
sgauvry Posted April 9, 2018 Author Share Posted April 9, 2018 Each injector should have two wires - a red for power and either a tan or a tan/white that goes to the EEC and is grounded by it. Red should be the same as battery power when the key is on - within a few tenths of a volt. And the tan or tan/white wires should go from battery voltage to almost ground (.7v) and back very quickly. The rapid changes will confuse your DVM, which is why a test light is better - it'll flash. Anyway, if you are seeing the voltage go all over the map then it looks as if the computer is telling the injector to fire. So, if you don't have gas then you must have low/no fuel pressure. Yes. There is power going to the injectors and there is ground. Fuel gauge reads over 60 and I know that fuel is getting through the rail. Link to comment Share on other sites More sharing options...
Gary Lewis Posted April 9, 2018 Share Posted April 9, 2018 Yes. There is power going to the injectors and there is ground. Fuel gauge reads over 60 and I know that fuel is getting through the rail. Strange. I'm lost as it would seem that fuel has to come out if you have power, the negative side is getting grounded, and you have fuel. Hmmm, what if your "power" isn't good? What if you have 12v when no injector is being told to fire, but that the power goes way down when an injector tries to fire? Can you put your DVM on the power going to the injectors and the other lead to ground, and then crank it? Watch the voltage and see if it stays up fairly high, or if it goes way down. A bad connection somewhere between the EEC relay and the injectors would do that as you'd have 12v when no current was being drawn but much less with current. Link to comment Share on other sites More sharing options...
sgauvry Posted April 9, 2018 Author Share Posted April 9, 2018 Just in case, I think I still have at least one of the 1985.5/86 EECs I scrounged up when Matt was fighting with his. Be sure circuit 349 is connected to pin #56 and is seeing a pulse. That is the PIP (Profile Ignition Pickup) which tells the EEC the engine is turning and after it receives the #1 pulse (short pulse) starts firing the injectors. So I did a few tests for my TFI module. (1) was for volts, (2) was for ground, (3) was for the ignition coil switching. And since the first three tests were as they should have been, I did not do test 4, which is for the PIP signal. If I do the PIP signal test while probing the number 1 circuit wire on the TFI, will that suffice as a test for what you are referring to? Link to comment Share on other sites More sharing options...
Recommended Posts