I have a 1983 280ZX non-turbo automatic. When it stays outside in cold weather it barely starts, sputters, smokes black like crazy and fouls the plugs. During warm weather it runs perfectly. If you start off warm and drive in cold, no problems. We've replaced the AFS but didn't change anything. Any Ideas???

 

Have you checked the CHTS, thermotime switch, cold start valve, and air regulator? Those are the 4 main components in cold starting.

 

I don't know what the CHTS so no we haven't replaced that. Tech says it's not a thermotime sensor becasue it doesn't do it by engine temperature but outside temperature, we replaced the MAF, and no on the cold start valve. I may not have been clear with my description so let me start again. If it is warm or sits inside a heated shop it starts and runs perfectly even if it is cold outside. If it gets cold it's hard to start, runs so rich it smokes black, and fouls the plugs. Over 60 degrees and it is perfect.

 

CHTS = Cylinder Head Temp Sensor. Located on the right side of the head between spark plug #5 & #6.

Somewhat correct... the thermotime switch is located in the thermostat housing, so when the engine is warm, it does not activate the cold start valve. When the engine is cold (I can't remember the exact temp right now... something like below 50*F) because it's been sitting outside, then it will activate the cold start to assist with idle. Bad thermotime switch or plugged cold start valve = crappy idle until warm.

So it's one (or more) of three possibilities... CHTS, Thermotime switch, or air regulator. Probably not the thermo or air reg since it's running rich. I'd bet it's the CHTS.

It sounds like you are doing this w/o a manual, so you should either buy a Haynes manual, or download the FSM for free at www.xenons130.com/reference

 

Had it in the shop with a supposed Z magician. He thinks it is a bad connection somewhere in the body! Can't imagine that and didn't want to just start replacing parts. I ordered all of the above and will keep you posted. Thanks for the help!!

 

Why??? Are you just going to replace every part of the engine until it runs right?

Why not test the sensors so you can pinpoint the problem, and save yourself a headache and some $$$ ?

 

... and if the connector or plug is bad or dirty replacing the part isn't going to fix the problem (unless it's the sensor side of the connector but that's the hard way to fix it when cleaning the connector on the sensor might work)... all of the above are in the EFI harness - not the body harness so I'm not sure what