5 Star Rising Posted March 7, 2011 Share Posted March 7, 2011 Have a 78 280Z that I just got. I bought it not running.. The car has been sitting for 4 years. Trying to get it started. So far I have drained the fuel tank and replaced a broken electric fuel pump. I have fuel pressure going into the fuel rail now but it wont start.. I can get the car to start for a few seconds by spraying starting fluid in the throttle body or by jumping the cold start injector. Any how I have no voltage going to the injectors, I replaced the ECU with a working unit out of one my other 280Z's (I have 4 of them) I also swapped out 2 differert MAF's and still no luck.. What other components could be stopping the voltage from going to the injectors? Temp sensor? Relay? Any one run into this problem before? Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 7, 2011 Share Posted March 7, 2011 (edited) The ECU doesn't supply voltage to the injectors, it just supplies the path to ground to energize the injector solenoids. So changing ECUs won't help that. The wiring diagrams in the Engine Fuel section of the FSM are small and easy to get through, and specific to your problem. Page EF-24 has a good one. Also, with four 280Zs, you should know that they don't have MAFs, they have AFMs. How it works is also described in the Engine fuel section. p.s. You should add a location or you might get locked out. From what I've been reading anyway. Edited March 7, 2011 by NewZed Quote Link to comment Share on other sites More sharing options...
5 Star Rising Posted March 9, 2011 Author Share Posted March 9, 2011 The ECU doesn't supply voltage to the injectors, it just supplies the path to ground to energize the injector solenoids. So changing ECUs won't help that. The wiring diagrams in the Engine Fuel section of the FSM are small and easy to get through, and specific to your problem. Page EF-24 has a good one. Also, with four 280Zs, you should know that they don't have MAFs, they have AFMs. How it works is also described in the Engine fuel section. p.s. You should add a location or you might get locked out. From what I've been reading anyway. Quote Link to comment Share on other sites More sharing options...
5 Star Rising Posted March 9, 2011 Author Share Posted March 9, 2011 Thanks.. yeah i have been out of the Z game for a minute. Is there a link to a FSM online that you know of??? Got 2 acres and 10 cars... (4) 280Z's (2) 240Z's (2) 97 turbo eclipses gst and gsx (1)71 Chevelle (1) 98 Chevy 3500 Dually and trailer (1) 2010 VW jetta for the wife lol... Your right i did call them MAFs lol my bad.. Any how I need to figure out if its a ground issue, I know I have had other ground issues though out the frame of the car but I only spent a small amount of time on this project so far.. Rob Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted March 10, 2011 Share Posted March 10, 2011 xenons30.com has the FSM I believe. You can try reading through the EFI bible, or get the pin-out for the ECU from the FSM and verify that the ECU is getting power and is correctly grounded. Quote Link to comment Share on other sites More sharing options...
5 Star Rising Posted June 10, 2011 Author Share Posted June 10, 2011 Well been busy with other things but I finally got around to messin with this project again yesterday. I pulled up the FSM (thanks for that) and Im still having trouble pinpointing the problem.. I know that when I turn on ignition I do not have power going to either of the injector pins of the injector harnesses, and when cranking the motor I still do not get power to the injector harnesses. I swapped out the main fuel injection relay and still nothing. I do how ever have power going to a few of the spade terminals on the relay but what ever correct spade/wire that feeds the injectors never gets power.. I tried 2 other AFM's and another ECU from my other cars and no luck. Could there be a bad sensor or other relay that controls power to the injectors? Also either of the pins on the injector harness plug are grounded.. There is no continuity to ground on either, should there be? Thanks Quote Link to comment Share on other sites More sharing options...
darom Posted June 17, 2011 Share Posted June 17, 2011 Rob, I am going to take a guess that the main grounding wire for the ECU is either broken and is making a poor contact. It runs from the ECU harness, goes through the f/w grommet on the LH side, then goes up along with the windshield wiper hoses and ends at the negative battery post. I am assuming this is how it is setup on your 78. Mine is 76 and I haven't checked the 78 FSM yet. The battery negative cable has a quick disconnect connector for the ECU wire which is usually in a pretty sad condition from being bent all the time while you disconnect your neg. cable. What I did on mine is to route the ECU negative wire to the starter negative bolt. The neg. battery cable goes into the same spot. Now I can disconnect the battery negative cable without disturbing the ECU's cable. Download the Fuel Injection Book, and run some tests for the control unit ground circuits: pages 57-60. Regards! Quote Link to comment Share on other sites More sharing options...
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