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77 280z, some fuel but not enough to start


ISPKI

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Hello Hybridz! I have been troubleshooting my 77 280z's inability to start for some time now. It is mostly stock. I have installed a 280zx distributor with an E12-80 ICM, headers, fuse blocks etc, nothing major.

 

I was having an issue with not getting spark out of the coil which turned out to be a broken ring terminal. I now get spark and the engine coughs for half a second like it wants to start but it doesnt. I have a fuel pressure gauge installed between the fuel filter and the fuel rail that reads a consistent 35-38psi. I got it started by spraying starter fluid into the intake but it wont run on it's own. It is acting like the injectors are not functioning so I will be reading into the test procedure on those.

 

I will keep updating this as I test, please give me any tips or hints that may assist and thank you in advance!

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Tony D has posted a good trick over on zcar.com, maybe here also, about connecting a jumper wire to your negative coil terminal, turning the key On, then tapping (quickly) the jumper wire to ground.  Every third tap should make all six injectors click.  That will test the wiring from the coil to the ECU and also what the ECU does with the pulse from the coil firing.  Every tap to ground does the same thing that the ignition module does (except "dwell time" control), and the ECU opens the injector every third spark (three sparks per engine revolution).

 

I've tried it, it works.  It's convenient also since there's no noise from the starter motor,  just the small zap of the wire hitting ground.  Easy to hear the injectors.  You could also take a meter and test continuity to Pin 1 from coil negative first since that needs to be there for the ECU to do its job.

 

Finally, one thing that I've found but some people have difficulty accepting is that the ECU won't fire the injectors if the tachometer and it's resistor are not wired in.  I've had the resistor fall out and the engine won't run, also tried to start two cars with tachs removed and they wouldn't start until the tachs were plugged in.

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Thanks for the tips so far guys. I tried your trick newzed. Stripped some jacketing off a wire, wrapped one end around the "-" on the coil, turned the key to "on", tapped the other end of the wire on one of the strut tower studs. I got nice little sparks but I could not hear a peep out of the injectors. I tapped the wire maybe a dozen times and got nothing.

 

I did test for continuity to Pin 1 and it is there. Guess I am going back to the FSM.

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