Cold Start Valve will not turn off/close

[zbane]

Not to terribly long ago, I started smelling gas after I parked the car. I poked around a little and quickly found gas on the PCV valve. By on, I mean you touch the valve and your finger becomes wet with gasoline. As far as I can tell, the only way gasoline could reach the valve would be via the Cold Start Valve. Thinking that the valve may be staying on longer than neccessary, I replaced the thermostat, checked the cleanliness of the sensors, and cleaned all the connections on the various thermostat mounted items (one was green with corrosion). Put everything back together, and drove 3.5 miles to work.

I thought it best to check all my connections for leaks once I got to work, and found the smell of gas once again. The PCV valve was one again wet with gas, so I do believe that the cold start valve is simply staying open/on. I have disconnected the contact to the valve, and will see if this helps. If not, is there a way to "convince" the valve to close? I was thinking about removing it and soaking it in a solution of some sort, perhaps carby cleaner, in case some crud made its way in there and is preventing it from closing. Any thoughts or suggestions?

I have a fire extinguisher in the car, and I really don't want to have to use it.

[zbane]

It's really slow at work (front gate job, fancy 99% seasonal housing community) so I jut pulled the Cold Start Valve and found it to be messy, but dry. The PCV valve was once again wet (I wiped it dry after the last photos were taken), indicating who know what as the culprit.

As per the FSM, I've tried blowing air through the valve, and am not able to.

[sblake01]

If I remember correctly, ZX's don't have thermotime switches like the earlier EFI cars and they get the signal from somewhere in the ECU. If your cold start valve isn't simply leaking, which I suspect from what you say, then check the connector for continuity with the car running. Hopefully, you won't find any since that woud mean that the problem is in you ECU. I don't like the 'blowing through the cold start valve test' and I use a vacuum pump to test them for leakage. I'm not sure I or anyone can blow 37+ psi.

[zbane]

Thanks Stephan, I'll check the continuity in the morning. You're right about blowing at 37 psi, but I don't think the valve is leaking, solely for the fact that when I removed it, it was dry, while the pcv valve was wet. Anyway, I'll dig deeper into the situation and keep all informed.

[zbane]

Well, I drove @25 miles to school today with the Cold Start Valve disconnected. Upon arrival I popped the hood to check for gas leakage, and there was none.

Odd thing-it was in the lower twenties when I started the car, and she started right up and idled/ran very nicely. I was under the impression that the CSV was to assist in exactly that sort of situation.

[deadflo]

If I remember correctly, ZX's don't have thermotime switches like the earlier EFI cars and they get the signal from somewhere in the ECU.

My 79 does have a thermotime switch.

[NH-75-Z]

I'd recommend removing it. I took mine off 2 yrs ago, no problems at

all. Starts at 24 degrees just like it was summer.

[zbane]

Turns out that the cause of the gas leak was not from the Cold Start Valve. I kept smelling raw gas after turning off the car, though it wasn't a constant occurance, even though the CSV was disconnected.

After some poking around, I found that one of lines connected to the Fuel Pressure Regulator was loose, possibly causing the gas smell. I decided to go ahead and replace the lines connecting the FPR to the rail, and when I disconnected the Vacuum Line (to remove the FPR), gas shot out from the top. Aha-the gas leak is found! As I thought about it, a couple clues were there that should have brought this possibility to mind: the car was taking more time to start up (building pressure in the rail), and was starting to act odd while driving (abyssmal MPG, hesitation/stalling when clutch is depressed)

So, I had to get ahold of a new regulator-Napa told me "wow, that's an outdated part. It'll take about a week to get one," but Advance said "we'll have one in the morning for you."

From now on, Advance will be getting my business...

So, if anyone is smelling gas in the engine bay (FI models), and can't find a leak, check your Fuel Pressure regulator.

[BuDavid]

good that you solved your problem David..

and thanks for informing us about the cause.

[76Datsun280z]

Glad you found/solved your problem, and that is good to know for future reference!