Ignition issue

[93 Z32]

Did plenum pull to replace injector over the weekend. Also did plenum coolant/ vacuum bypass as well. Put it together. Started it up and let it get to operating temps to checks for any leaks. Actually started it up several times. I'm the type that measures 3 times before I cut. Lol.
So it ran awesome. Woke up the next morning, car wouldn't even turn over. But EVERYTHING ELSE worked. Lights, dash lights, radio, could hear fuel pump prime, wipers worked, just wouldn't turn over. So I go out this morning, and it fired right up. Previous owner replaced PTU. I ordered PTU sub harness from Z1 this morning. As the harness now is pretty well corroded. All coil packs are fine. New NGK plugs. New TPS.
Do u think my problem is the PTU harness being corroded? Or possibly ignition/starter relay? The PTU is still in factory location. Was never relocated

Any input would be greatly appreciated.

[300ZXttZMAN]

Well well well a fellow Z32 owner from LA My name is Mark I have a bunch of friends going to school at LSU and some at BRCC.

The Z32 general section is for general discussions. The Z32 tech section is the place for this type of thread. I am going to go ahead and move it to the Z32 tech section.

As for the question you have I have no clue. I would start by checking the wiring like your doing.

Good luck.

[RubyRed300ZX]

Check the starter relay first. They do go bad. With mine, I could actually hear it rattle while shaking it. The clue with mine was that just slamming the drivers door (relay is inside the drivers front fender) could cause the relay to either work or not.

[93 Z32]

Ah. I have one on order along with a new PTU. I had to get it towed home today. My new PTU sub harness was waiting on the steps for me. Installed that, fired right up. But I'm not taking any chances so I ordered a new PTU as well. Car will be new when I'm done with it. Replaced injectors, TPS, pcv silicon hoses(red from Z1), new transmission mount, 1 piece driveshaft, battery, NGK plugs, pads & rotors, Megan racing type2 catback and down pipes, coil pack connectors, coil packs, new vacuum lines throughout.
I did notice that the guy that had this car before me, didn't put any grease in the PTU sun harness. With that being under power 100% of the time while the car is on, it needs that grease to keep from corroding/shorting out. Those harness connectors were green like a Christmas tree.

[93 Z32]

Hmmm. Interesting. What's that have to do with ignition issues??

[GerryO]

Started it up and let it get to operating temps to checks for any leaks. Actually started it up several times. So it ran awesome.

Woke up the next morning, car wouldn't even turn over. But EVERYTHING ELSE worked. Lights, dash lights, radio, could hear fuel pump prime, wipers worked, just wouldn't turn over.

So I go out this morning, and it fired right up.

Any input would be greatly appreciated.

Is the car garaged at night or parked outside?

Has the weather been cold and damp, or warm and dry?

Baton Rogue, LA is coastal = salt air = things rust/corrode? Dielectic grease is always a good idea on all connections other than those associated with the MAF.

How old is the battery? Things sat idle for only a few days, while you were doing the plenum work? Have you cleaned/wire brushed the terminals and the inside of the cable connectors, and tightened the cable connectors? Not much current is needed to power lights and accessories, compared to what is required to turn over the starter and engine.

[93 Z32]

Battery is only 4 months old. It's my daily driver. So it doesn't sit long. I cleaned all the plugs and used the dielectric grease on them. Changed out the PTU and PTU sub harness, new ignition/starter relay. New vacuum lines. New TPS. Turns out, web I pulled the plenum, the vacuum line going from the fast idle air control valve to the balance tube was cracked on both ends. I had extra 1/2" heater hose laying around. So I used that since it was 12:30 at night on Saturday. But since that line is a preformed molded line, the 1/2" heater hose was collapsing and choking itself off, causing the car to die. I ordered a new hose from Z1. New silicon (red) hose. Put it in, runs and starts like it should. Now I just have to adjust my TPS and set my idle.