Drain plug and thermotime switch

[78 280zcar]

Does anybody know exactly where this drain plug is on the block I cant find it , in the book it says its on the left side but thats all it says, and also what would happen if the thermotime switch were to go out in a fuel injected Z. Thanks

[TomoHawk]

I talked to a datsun hot-rodding guy in CA, (darryl reilly 408-988-8457) and he told me that if the thermotime switch isn't working right, you'll be running rich., so change that.

Thermotime switch is near the thermostat. Look for a 19mmm nut thing. I think it's about $50

[78 280zcar]

would that cause my car to run rich after letting it sit. Heres what is wrong with my car, after driving it on the freeway and park it, after about five minutes I try to start it and it starts but sputters like it has too much gas in the intakeor running to rich like it is shooting gas from the cold start valve even when it is at normal temp. would this be the thermotime switch because it is hooked up to the cold start valve. Thanks

[TomoHawk]

I think you're right.

The thermotime switch is part of the cold-start circuit, so it'll shoot some fuel in there when cold. So if it's not working right, you'll probably always have a "cold-engine situation."

It's an easy DIY thing to fix a rich mixture problem. Other than that , it's probably something complicated.

[Ben]

If the Thermotime switch goes OC, the engine will run poorly when cold (and may be hard to start).

If it goes short, then the cold-start valve will be always open, making the engine run rich all the time.

An easy test is to remove the electrical connector from either the switch, or the cold start valve & check engine behaviour.

The drain plug is at the LHS-rear of the engine, under the exhaust manifold. Chances are that it is rusted solid to the block.

[78 280zcar]

Thanks you guys, should I unplug it and then try to start the engine, also when I changed the fuel pump and fuel filter it says to take out the cold start valve and turn the engine over to let out the fuel from the system and it did not let any fuel out of it that I could see, is there suppose to be alot of fuel come out or just alittle. Merry Christmas. Thanks

[78 280zcar]

What is it suppose to do when I unplug the connectors. Thanks

[Ben]

If you un-plug either the thermotime connector, or the cold-start injector, the car will not be able to inject auxillary fuel when the coolant temperature is under 18 deg C. HOWEVER, if the cold-start injector is leaking, then it will continue to leak.

You can harm nothing by unplugging either of these components.

[TomoHawk]

how can you tell if the cold start inector is leaking? Is it under pressure?

[Ben]

The cold start injector is subject to the same fuel pressure as the rest of the EFI system. If you remove it you should be able to visually inspect the nozzle for leaks.

[78 280zcar]

Thanks for the info guys, Ive been really sick and havent had a chance to reply or do anything to my car. But thanks Guys. And also should I disconnect the cold start valve when the car is cold or before starting it to see if it starts. Thanks

[78 280zcar]

I disconnected my cold start valve and it didnt do anything at all it ran the same, does this mean that my cold start valve is out. Thanks