74 would just shut off

[juvius]

Another PO screw up thread: (troubles like this are hard to diagnose and find. I got lucky and found it before I got out the sledge hammer)

The 74 i bought was making a terrible noise while running. Alan (SoFloFiat) was kind enough to hook me up with a replacement head. Install was smooth and the car started right up and sounded good (as good as it could without being timed and carb adjusted). It would heat up and shut down. Not stall, but shut off like i turned the key off. I actually almost decided to park it at my dad's and let it rot...

after checking for vacuum leaks, checking the idle solenoid had 12v, and swapping out the coil, I noticed the temp gauge wasn't moving so i checked out the green wires on the temp sensors at the top of the engine thinking i reverses them. For some unknown reason, the PO or the PO's PO decided that those two wires needed to be 12v. The connectors were cut off when i went to plug them in. I didn't remember cutting them, but i though i must have cut them by accident and put connectors back on. turns out they were not hooked up when i got the car.

So what was happening was, since the wires were 12v, when the engine got up to temp and activated the switch that moved the gauge needle, it was introducing 12v directly to the engine, which is ground and shutting it off. after i figured that out, i found another wire the po ran directly to the gauge to fix the problem. he didn't bother running another wire to the overheat light, so i'll have to get that done.. but first i'm going to trace the green and green-black wire down to see what the hell they were doing...

[paintdudeluke]

Nice catch, that would have had me thinking for a while. Sometimes the weirdest crap that should have never even been an issue ends up in your lap.
I got a car one time where this guy had for some idiotic reason bypassed the radiator and had the hoses just looped out and back in the engine. The weird thing was that he also connected the outlets on the radiator so it would hold water. It would warm up and boil out every time by blowing a hose off. imagine that.... He said it had a new engine and didn't understand why it was getting hot because the radiator never got hot, just the engine. When I started to look it over I was in disbelief at what I was seeing. The hoses didn't even fit the right way, he must have had a parts mix up or whatever, who knows. Anyway, I got the car for next to nothing and it turned out to be a great running little 280z.

[juvius]

that's nuts... some people have no business working on cars... sometimes, i think i'm one of them..

[SoFlaFiat]

Of all the things I've lost, I miss my head the most....