280z-racer Posted July 30, 2009 Share Posted July 30, 2009 havent been on in a while but here is where im at- my z will crank but has no injector pulse. i do have spark because it will fire on starting fluid but wont run for more than a second. i originally had no power to the injectors or fuel pump. now i have 9 volts to the pump and voltage to the injectors but no pulse. swapping ecu's and airflow meters with known good units does not chnage results? any thoughts on this are appreciated. Quote Link to comment Share on other sites More sharing options...
280z-racer Posted August 7, 2009 Author Share Posted August 7, 2009 no one? Quote Link to comment Share on other sites More sharing options...
WildBill Posted August 8, 2009 Share Posted August 8, 2009 I don't have a service manual to reference right now, but the injector signal comes from the ecu. If you swapped it out and still no go, then either the ECU is not getting the signal it needs, or have a power or ground problem. Not sure where it gets it's signal from, i.e. module, distributor, etc. but a wiring diagram would help out a lot, do you have a service manual? Quote Link to comment Share on other sites More sharing options...
280z-racer Posted August 8, 2009 Author Share Posted August 8, 2009 not for a 77. but the 76 seems to be pretty similar. i figured my next step was to go through the harness pin by pin, but i was hoping someone might have a more direct idea. Quote Link to comment Share on other sites More sharing options...
sweetleaf Posted August 8, 2009 Share Posted August 8, 2009 How are you testing for the signal at the injectors? Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted August 9, 2009 Share Posted August 9, 2009 not for a 77. but the 76 seems to be pretty similar. i figured my next step was to go through the harness pin by pin, but i was hoping someone might have a more direct idea. actually, they changed quite a few things in 77-78 compared to 75-76, but I don't think anything too important to why your car won't start changed http://www.xenons30.com/reference.html they have the FSM for pretty much every year of the Z, so go ahead and download yourself the 77 FSM the EFI bible is also pretty good to have if you don't have it already Quote Link to comment Share on other sites More sharing options...
240ZNTX Posted August 9, 2009 Share Posted August 9, 2009 Check your negative coil connections. Thats where your ECU gets it's signal from. Sounds like you might have knocked a wire off or lost the connection. Check the the little spade connections on ballast resistor on the coil also. If your troubleshooting at the ECU connector... the number 1 pin is the trigger signal for the injectors coming from the negative side of the coil. It also feeds your tach signal. If you have a pulsed signal there...then you have a good signal going into the ECU. Be sure you havent bent any of the prongs or damaged the female spade connections at the ECU also. If all that is good...check the connections at your dropping resistors. The problem has to be either one or the other. Good luck Quote Link to comment Share on other sites More sharing options...
280z-racer Posted August 10, 2009 Author Share Posted August 10, 2009 actually, they changed quite a few things in 77-78 compared to 75-76, but I don't think anything too important to why your car won't start changed http://www.xenons30.com/reference.html they have the FSM for pretty much every year of the Z, so go ahead and download yourself the 77 FSM the EFI bible is also pretty good to have if you don't have it already the 77 manual is corrupt. Quote Link to comment Share on other sites More sharing options...
280z-racer Posted August 10, 2009 Author Share Posted August 10, 2009 Check your negative coil connections. Thats where your ECU gets it's signal from. Sounds like you might have knocked a wire off or lost the connection. Check the the little spade connections on ballast resistor on the coil also. If your troubleshooting at the ECU connector... the number 1 pin is the trigger signal for the injectors coming from the negative side of the coil. It also feeds your tach signal. If you have a pulsed signal there...then you have a good signal going into the ECU. Be sure you havent bent any of the prongs or damaged the female spade connections at the ECU also. If all that is good...check the connections at your dropping resistors. The problem has to be either one or the other. Good luck sounds good. i will have to give that a try. it might just be that simple! Quote Link to comment Share on other sites More sharing options...
280z-racer Posted August 19, 2009 Author Share Posted August 19, 2009 well after going through the test procedures is the manual for wiring and components, i have found that i have no continuity through the air regulator and low voltage on the thermotime circuit. can either of these cause there to be no injector pulse? i checked for voltage at the #1 pin on the ecu connector for the ignition trigger and there is voltage there. other that im at a loss. Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted August 21, 2009 Share Posted August 21, 2009 got a spare themotime to try? it's possible it may not be working. You may bypass it, but you'd have to wire a resistor in place. Quote Link to comment Share on other sites More sharing options...
m4xwellmurd3r Posted August 22, 2009 Share Posted August 22, 2009 You can just unplug the thermotime. That won't cause it to not start. The thermotime switch only activates the cold start injector, and that only kicks in when it's REALLY cold out. I wouldn't know about the air regulator though. I never tested mine. I don't even know if mine is plugged in or not >_> Quote Link to comment Share on other sites More sharing options...
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