slownrusty Posted February 18, 2008 Share Posted February 18, 2008 Hi Gang - I took my '78 280Z for a spin yesterday, it ran awesome but the only issue was the rebuilt Unilite Alternator was not charging properly, it was barely making 11V instead of 14V. I noticed this alternator has been acting up lately. Today I decided to change this alternator and the car refused to start whatsover this morning. The car has a new battery and I cranked and cranked and cranked and nothing (it cranks just fine too). - There is lots of fuel to the injectors - confirmed by popping off hose coiming out of the fuel filter. - I switched the AFM with a good working spare - nothing changed - I am getting lots of spark at the coil - confirmed - I checked all the fusible links and they are perfect (in fact they are only 1 month old) - I then checked the injectors and none are firing, I have that little Bosch tester that you plug into the injector harness plug and it did not illuminate and then further confirmed by putting starter fluid into the intake and none of the injectors are firing. I am really worried (mixed with anxiety and generous helpings of fear) that maybe something fried in the ECU - is this even possible? Unfortunately I do not have a spare pre '78 ECU to test. Are there any other relays or place to look for further trouble shooting? Please let me know, I am desparate and glum Thanks- Yasin Quote Link to comment Share on other sites More sharing options...
GrommitZ Posted February 19, 2008 Share Posted February 19, 2008 Hi Yasin, I'm unclear about your confirmation using starting fluid. Do you mean that the engine started once you sprayed the starting fluid into the intake manifold? Have you checked to see if the plugs got wet? I hope you figured it out. Maybe you should double check your connections to the alternator, since that's when the starting problem started. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted February 19, 2008 Share Posted February 19, 2008 gotcha covered. sending you out a '78 ECU ! Quote Link to comment Share on other sites More sharing options...
slownrusty Posted February 19, 2008 Author Share Posted February 19, 2008 Hi Yasin, I'm unclear about your confirmation using starting fluid. Do you mean that the engine started once you sprayed the starting fluid into the intake manifold? Have you checked to see if the plugs got wet? I hope you figured it out. Maybe you should double check your connections to the alternator, since that's when the starting problem started. Grommit - No the engine did not start when I sprayed the Started Fluid into the intake. Plugs are dry. And all the alternator connections are perfect and solid. Hence the frustration I have an ECU on loan from Ryan coming my way...so X-fingers that is the culprit. Thanks again Ryan!!! Regards - Yasin Quote Link to comment Share on other sites More sharing options...
MJLamberson Posted February 19, 2008 Share Posted February 19, 2008 well did you try putting the old alternator back on? that would be my first step cause it was essentialy running fine with it Quote Link to comment Share on other sites More sharing options...
slownrusty Posted February 19, 2008 Author Share Posted February 19, 2008 Well I just went back outside and I am only getting 0.3Volts (!) at the injectors plug as I am cranking.....so my conclusion is that its probably the ECU - cross fingers. I dug up one of Paul's (BRAAP) oold posts and it was helpful. Yasin Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted February 19, 2008 Share Posted February 19, 2008 Yasin, If I remember correctly, the injectors are connected to a switched power source. I need to recheck the wiring diagram, but I believe the injectors are powered with the ignition switch in the on, and start position, by use of the EFI Relay. Mario Quote Link to comment Share on other sites More sharing options...
slownrusty Posted February 19, 2008 Author Share Posted February 19, 2008 Yasin,If I remember correctly, the injectors are connected to a switched power source. I need to recheck the wiring diagram, but I believe the injectors are powered with the ignition switch in the on, and start position, by use of the EFI Relay. Mario Mario - Are you thinking the EFI relay might have gone south? Until I receive that loaner ECU from Ryan, I am considering every possibility (run through that check list so to speak). Regards -Yasin Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted February 19, 2008 Share Posted February 19, 2008 Yep! http://www.atlanticz.ca/zclub/techtips/wiringdiagrams/78-280Z_wiring.gif (I don't want to show it as it is a huge picture, but click to see it) One side goes directly to the ECU. The other goes to the dropping resistors which are then fed power with the EFI relay. Check the connections at the relay as they are definitely getting some power, so the connections might be corroded. One side of the connector is always hot (+12v) with the key in the on position. The ECU then grounds the injector to fire it. Mario Quote Link to comment Share on other sites More sharing options...
slownrusty Posted February 19, 2008 Author Share Posted February 19, 2008 Yep!http://www.atlanticz.ca/zclub/techtips/wiringdiagrams/78-280Z_wiring.gif (I don't want to show it as it is a huge picture, but click to see it) One side goes directly to the ECU. The other goes to the dropping resistors which are then fed power with the EFI relay. Check the connections at the relay as they are definitely getting some power, so the connections might be corroded. One side of the connector is always hot (+12v) with the key in the on position. The ECU then grounds the injector to fire it. Mario Thanks bro...will definitely check that out in the next day or so and reprt back! My best - Yasin Quote Link to comment Share on other sites More sharing options...
silver280zx Posted February 19, 2008 Share Posted February 19, 2008 check the power wire to your igntion system. If not that look at the coolant temp sensor, itsa like 10 bucks, and then the ignition relay. Quote Link to comment Share on other sites More sharing options...
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