shanegarr

I recently rebuilt a vg30 for my 86. I replaced all of the injector wiring also and soldered all connections exactly to the point of the factory wires. all of the connectors were broken, that's why I replaced them all. When I got it ready to fire up it wouldn't start. would turn over fine, new battery also, and the fuel pump was producing correct pressure, new regulator also. took the plugs out and they are sparking but were dry. I replaced the coil, dist cap and rotor anyway but made no difference. made sure was at top dead center and the distributor was not 180 degrees out. I messed with it for a couple days checking every wire and connector that I could find. I don't know what I did but if finally started and ran great???? I went ahead and drove it for a couple weeks to break it in. Changed the oil and went on a road trip. have about 1300 miles on it now and it was still running fine. got home from work last night shut it off and all was good. went out this morning to leave for work and it won't start again. Just like the very beginning, I have spark and fuel pressure but I don't think it's getting fuel into the cylinders. Nothing I do makes it even try to start. Just spins and spins. I'm at a loss and don't know what to do next.

NismoPick

Welcome to ZDriver!

Have you checked the ECU diagnostic codes?

shanegarr

I checked the codes and got 13 I had unplugged the cylinder head temp sensor and plugged it back in, that's prob why. I replaced it anyway. I got 21, I replaced the ign coil, dist cap, rotor, wires and plugs. I got 23, I replaced the TPS and the wiring harness. And I got 31, I no longer have a AC on the car. Forgot to mention that it is a NA 5 speed. Another question. I checked the voltage at the injector plugs and had 12 volts on the red wire, whether the key was on or off???? When I replaced the connectors I didn't use the exact same gauge wire as stock, my wire is a little larger. Didn't know if that would make a difference

shanegarr

Here are two pictures of the inside of my ECU. I don't know if the green component or resistor or whatever it is beside the 15 pin connector is supposed to have a yellow top or if that means it is bad. None of the other ones on the board are like this one.

rogerz

don't think that is your problem. Probably a capacitor and just got a yellow mark for some reason to identify it. Codes usually just cost you money with no real value to diagnosis.
Get your battery load tested. Be sure you have clean, tight corrosion free terminals on both ends of your battery cables. Be sure the ground (negative) cable goes to a bolt into the frame before going to the starter. grounding through the starter is not a reliable connection. Z's don't like low voltage. causes the electronics to act funny. it is possible to have enough amps to crank but not enough voltage to run the electronics. If you have one size fit all cheapo clamp on terminals they are a problem waiting to happen. Usually on a rainy night around Oh Dark Thirty. Many people ignore the battery and cables but this is the heart of your electrical system. grounding to the body before going to the starter is critical. Check your fusible links with a vom and be sure they are properly seated. check and reseat all your fuses. Your problem seems to be electrical because it killed the car after running properly for weeks. spray some starter fluid in the intake and see if you get a vroom. you at least know your ignition and air intake are okay after that. recheck your fuel pressure. be sure no vacuum leaks. take a plug out and see if it is wet.


When trying to start without success you can easily inject enough unburned fuel to effectively flood the engine (using old carburetor terminology). this then prevents you from starting the engine normally. If you have checked everything and still no luck try this. disconnect a wire from the fuel pump so it won't pump (on a z31 pull the fuse). you need a fully charged good battery for this. hold the gas pedal to the floor and give it a long crank. you may or may not get a few pops. Do it again. it may run for a few seconds. do it again. When you no longer get any action reactivate the fuel pump and try a normal start.

shanegarr

Well My son and I figured it out. About the only thing I didn't replace was the power transistor/ignition module. I didn't replace it because it was pretty expensive. Luckily we have several z cars as parts cars and had one of the modules that was good. put it on and it started right up. I also completely removed the injector plugs and wire harness and rewired the whole thing, soldering all connections again. Don't think that was the problem but it made me feel better to go ahead and re do it all. was still getting code 23 because I had never adjusted the TPS per the FSM. Once that was adjusted that code was gone as well. The only code I get now is 31. Can't do anything about that I guess. Thanks for all the help.