4.6StangRage Posted October 19, 2011 Share Posted October 19, 2011 first, I have downloaded the EFI PDF file and looked it over. I have done all of the no start troubleshooting I could until it instructed me to plug in another ECU and give that a try. A pulse is evident from coil to ECU I get an 11 volt signal to each injector terminal (in other words, no ground signal) I plug use my LED test light, which has green and red LEDs, red for power and green for ground and i get a pulse in that case not when an incandescent bulb is plugged into the injector plug. I have consistent fuel pressure, spark and compression is normal. I have used artificial fuel to confirm this along with the conventional methods I have tested all circuitry coming from the ECU and everything is going where it is supposed to. All signs point to a faulty ECU, but I am nervous about replacing it. I want to be sure about it and i want to test the unit itself. I swear up and down that there is a way to Test the ECU by continuity and resistance values through pin to pin in the 1975 Datsun 280Z factory service manual. Does anyone know where to point me when it comes to finding a proper diagnosis on the ECU itself? Thanks for reading!! Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 20, 2011 Share Posted October 20, 2011 Spray Starting Fluid down the intake and see if it catches. If it doesn't, it's not your ECU. Pulsing of the injectors is all you need. If you've flooded it, it can take three days to dry out! "Hot Plug" and burning out the combustion chambers may help in this instance... A little sparse on details, but it looks like you're missing the forest because of all the trees in the way. Quote Link to comment Share on other sites More sharing options...
4.6StangRage Posted October 21, 2011 Author Share Posted October 21, 2011 I already did that and yes it starts and runs for a few seconds. Quote Link to comment Share on other sites More sharing options...
JSM Posted October 21, 2011 Share Posted October 21, 2011 (edited) Edit: NM. Miss read. Re-edit: Did you do all the test from section EF-21 (Engine Fuel - Page 21). From Xenon: http://www.xenons30.com/reference.html Edited October 21, 2011 by JSM Quote Link to comment Share on other sites More sharing options...
ModernS30 Posted October 22, 2011 Share Posted October 22, 2011 It is most likely your main fuel injection relay. Its a little NLA $125 dollar junky relay. I found one used on ebay for $25 dollars when mine went out, I was having the same issue. Trace your power into and out of the relay. The FSM is your friend, it will take some time, I traced all over the place before I figured it out. It plugs into the harness with two plugs, a black and white box connector. Quote Link to comment Share on other sites More sharing options...
4.6StangRage Posted October 23, 2011 Author Share Posted October 23, 2011 I located a short in my FI harness and repaired it and then I discovered a short in the corresponding injector. I unplugged the injector and the Z started up. btw I did use the EFI bible and the Nissan Factory manual and it did not mention to check resistance in the injector. Quote Link to comment Share on other sites More sharing options...
s30red240z Posted October 23, 2011 Share Posted October 23, 2011 I think we are talking about L28E. The ignition system is independent from ECU, the distributor only sends a tach signal. I think that could be a resistor package problem, main relay, or damaged ECU. Quote Link to comment Share on other sites More sharing options...
4.6StangRage Posted October 23, 2011 Author Share Posted October 23, 2011 I got it running yesterday and it was shorted injector wiring which eventually led to a shorted out injector. It runs on 5 cylinders but nevertheless it is running. Quote Link to comment Share on other sites More sharing options...
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