Switchtr3

So I haven't been to zdriver in a few months...
I may be buying another Z tomorrow. It's another '81 n/a 5spd two seater, exactly like my last one. This one is a slicktop and it is a different appearance package (different rims and paint scheme). I'm gonna miss the t-tops a lot, but at least the interior didn't get cooked. It's in pretty nice shape overall. A 29 year old car is gonna have a little wrong here and there but the is interior great, the floorpans and passenger side frame rail are new.

Now I might be getting this for a steal, the guy said it was his DD for the last couple of months since his other car died. Now he wants to sell it because it is real hard to start in this ridiculously cold weather. I'm gonna bring a compression tester cause I know a bad HG will make for a hard winter start. He suggested it may be a problem with the cold start valve because it always ran fine before it got cold. I have a complete running engine just laying around from my accident so if something is terribly wrong I can swap it, but it wold be so much easier just to fix this stupid valve (if that's what it is)

Anyone have any ideas what it might be? Do these cold start valves go bad often? I remember my last Z also started a little hard in the cold weather, but I never had it in this 10 degree BS. All advice is appreciated, and sorry for rambling...

Feels good to be back at zdriver.
I have felt an empty space since august. I can't wait to get back in a 280!

Niku-Sama

ok well the cold start injector could have gone out in it or the Auxillary Air Valve (AAV) is stuck.
mine gets stuck from time to time, i take it off, hose some brake clean in it and then some WD and it moves a bit more freely than before.

my guess if it just does not want to start in cold weather than its the injector, if the AAV mine would still start but try to stall comming to a stop or just didnt want to run well after it started

NismoPick

-Dirty / clogged cold start valve
-Bad thermotime switch
-Bad air regulator
-Misadjusted AFM
-Misadjusted timing


Those would be the main culprits.

Switchtr3

Thanks for the input!
Yeah, the car runs and drives great once you get it running. When it's finally warm it will start no problem. It is only a problem to start when cold and the temperature is cold outside too.

bluesky6

There's also a cylinder head temp sensor. It's near the oil filter. At the minimum, check the cleanliness of the electrical contacts.

I was having cold start weirdness and changed both the thermotime switch and CHT and that seemed to fix the problem.