So I haven't had cold start in the mornings here and I should because it is usually below 60 degrees when I go to work. I noticed its been harder to start my Z for the past 2 weeks. I measured the TT this morning and I should have got a reading somewhere around 2.96, ambient temp is 59 degrees. I got no reading, 0.00. So off to find a TT. I wonder what killed it? Its only about 4 years old.

I've only had two meters, one with a needle and another that has auto-ranging. Touch the probes together on your meter and see if you get a "1".

That would be a no. Touch them together and I get 0.00

It seems to be open then. Now you have to consider temperature. It opens at 57 - 72 degrees F. Down in CA, it should probably be open by now. Google says you're at 70 F.

Might have to wait until it's cold, or pull it and put in the refrigerator. In the meantime, are you sure that your fuel pressure is holding? A dry fuel rail will cause a similar problem.

No, the fuel pressure doesn't hold. I have a gauge on the "supply" side between filter and rail and it drops off over a few hours. Maybe I just think it should be cool enough for it to work. Im in Oxnard, a few degrees cooler than Ventura. Right now at the Oxnard Airport it is 67 degrees. This morning when I tried starting it it was 59 degrees, should have worked then.

Seems odd that it would only open between 57 and 72 degrees. What if its -57 degrees?

Edited June 1, 201410 yr by rcb280z

I should have said "switches", in that range. I was thinking in one direction, warming. In the other direction, cooling, it would close in that range.

How hard is hard to start? Maybe you're asking too much of an old car.

It usually fires right up. Now I have to crank it over twice and then it stumbles for a couple of seconds and then idles around 1400 rpm until it starts to warm up.

It isn't an issue really. I dont have to have the cold start working but it would be nice. I just know there is a problem somewhere and that I don't like.

Ok so this morning she fired right up like she normally would. It was 54 degrees F when I started it. Now I know when the cold start will work and not work.

I don't think there's anything about an old car that should keep it from starting reliably, but this may be a case of an old DESIGN not starting as easily as a modern one. Back in the day, we would frequently have to bump the starter a couple of times to get running.

An interesting mod might be a push-button under the edge of the dash (or somewhere where it is not easily pressed by accident) that would actuate the CSV. We could use it like the priming bulb on a lawnmower! Of course it would be easy to prime too much and flood the engine.

Hi FastWomen, I had a thought last night regarding the Z running a little lean. It showed it in the emissions test I just had so I knew I could richen her up a bit. So I adjusted the bypass screw in about a full turn and when I started her up this morning it fired up the way it is supposed to, right away. So if it does the same tomorrow morning I'll know that I have fixed the problem, so to speak. And my fuel pump check valve is bad, doesn't hold pressure past 5 hours. So I think that is pretty good.

I wired in a toggle switch to the CSV about five years ago while I was waiting for my thermo time switch to show up. It worked perfectly for that whole week. Better than the cold start system "sometimes". If I ever need to wire the toggle back in it's in my toolbox ready to go.

RCB, Interesting about your bypass screw! I've adjusted mine in and out -- from all the way closed to screwed out almost to the point of falling out -- and it doesn't impact my idle mixture the tiniest bit! I wonder why. It doesn't seem to be clogged or anything.

Although it would be great if your check valve held pressure longer than 5 hr, I think 5 hr is certainly enough. As I understand it, the Nissan dealerships had a policy of replacing them if they didn't hold pressure for at least 2 hr, so they would have considered your check valve still good. Their only purpose was preventing hot restart problems, which apparently you're not experiencing (much).

Definitely not experiencing the "hot restart" problem. When I spent some time in Las Vegas (17 years) I had the hot restart problem a few times but not every time. Not sure the outside hot temps has anything to do with it but maybe? I don't recall but has anyone inquired about the daily temps when the issue is present?

As far as the bypass screw goes, you should absolutely see small changes between rich and lean. Drastic changes with the "clock spring" and fine tuning changes with the bypass screw. Wonder if its due to the "pot" you have wired into the cold start circuit.

After I told you 5 hrs last night I decided to double check to see how long she holds pressure and it doesn't even hold for 2 hrs so..... But not an issue yet. When it starts causing a problem I will tackle it. See purs like a happy kitty right now and I am jazzed. Don't know if you read my thread on the emissions test but it's nice to see hard work pay off, for a change. CA is really strict and more so in some counties.