I have a freshly built z6 with vitara/eagles. head is all stock but was examined by machine shop and had a valve job done. All machining work was done by a reputable shop in my area, but i personally assembled the block myself using a helms manual to the T.

The issue: motor is in the car but it won't start. It gets fuel which i checked for by simply disconnecting the fuel return line from the rail. It does NOT however have ANY spark on ANY cylinder. The distributor is a brand new oem replacement with a brand new cap and rotor. Im using a rywie distributor conversion harness because the z6 is in a 00 coupe. Im using a chipped and converted p75 ecu that was the same ecu i was running before i pulled the motor out. Its using a neptune basemap setup to run with my gm 3 bar map sensor. I tried another distributor to see if that would get it any spark but no luck. From my understanding, this means the next culprit of cause should be the main relay, but would that go bad while the car was just sitting? what else should i look into? any and all help appreciated, thanks HT.

 

I'd start by verifying that you are getting 12 volts to the distributor.

 

Yes check for 12v at the distributor. Most likely you dont or no negative. Trace back from there

 

check your ground at the thermostat housing! if it has a bad connection or is not connected, NO SPARK / NO FUEL

 

Checking fuel flow at the return line only confirms that fuel pump is running.

You need to confirm if you are getting fuel into the cylinders. If you have an injector test light, check if you have injector pulse.

No pulse means no fuel.. No fuel and no spark could be caused by several things; like poor grounding for the ECU sensor signals (the ground strap on the thermostat). It can be caused by a lack cam/crank/TDC of signal from the distributor (wiring, or a bad distributor out of the box).

If you have fuel injector pulse but no spark, then it will narrow down your issue to being the ignition system only. It will be distributor system related, or distributor wiring related. From there on, the easiest thing to do is swap to another distributor, swap to another ECU, or trace wiring for proper voltages.

 

Results:
Fixed the no spark issue! there was indeed a loose connection in the adapter harness and i easily fixed that, which fixed the no spark issue but the car still would not start and was throwing code 16 still. Next, we unplugged the fuel rail from the head and attempted to start the car to see if the injectors were pulsing and they aren't. So my problem actually is that I'm getting spark and no fuel. After a little research, I found out that a bad main relay will throw code 16 and cause the injectors not to fire. Can anyone confirm or deny this? I also tried another ecu just for the hell of it, but no change. If it matters, I'm using precision 880's with in line resistors. None of the injector wiring has been altered since my last setup and i rechecked it all and everything is fine with the wiring. Any other ideas while i source a good main relay to try out?

 

You could jump olthe relay and see if things start up.
Relay is simply a coil and contact. U need a diagram to do it right though.

 

yes sir! I use this method at work when diagnosing any relay concern!

 

id just replace the relay they dont cost much.

 

Or test the coil in the relay. Do it right dont just swap parts. To test the coil you need an ohm meter. Im not positive but I think that relay has 2 coils and two sets of tips.
Or you can check the voltage going into the coil. If you dont have voltage there you have to trace your wiring back from there. Or if you dont have a ground to the coil it wont close either.
Think of the relay as a light switch instead of flicking it on with your finger your using a small voltage to.close the switch.