Sometimes my 85 300ZX Turbo will not start on a warm day. The vehicle starts fine all through winter and early spring up until Mid May when it begins to get warm.

The car has power, but the fuel pump will make a buzzing and clicking noise.

Nissan put in a new ignition coil, remanufactured distributor, and power transistor unit. They also said it could be the ECU, but I decided not to have that done because it is very expensive, and I think they were just guessing at what the problem could be.

In summary, the vehicle starts fine late September through mid May. When it gets warm, I get that buzzing and clicking sound and the vehicle will not start.

I am completely baffled and do not know anyone experienced enough with these cars in my area to properly diagnose the problem.

If anyone on this board has experience working with imports, or 300zx in particular, I'd really appreciate any suggestions or solutions to this strange problem.

Cheers

I would:

. Clean the main ECM ground with abrasive cloth.

. Apply a thin, even coat of silicone heat transfer compound to the back of the Ignition Control Module (ICM).

If the problem persists, I would focus on the ECM. The buzzing may be from the EFI Relay, due to an ECM grounding issue. The buzzing relay is the effect, the failure of the ECM under load (heat) is the cause. This is a common problem in old ECMs, where electrolytic capacitors and micro-processors begin to fail due to heat.

That makes sense because when I unplug one of the connections from the ECU, the buzzing stops. The only thing I can't tell is if the problem is with the ECU itself or the wiring. Guess the only option is to replace the ECU and see if it goes away.