Itinerant Air-Cooled

Bentley says I need to ground the "W" side of the thermotime switch plug to test the Cold Start Valve.

It occurs to me that I should be able to just apply 12V directly to the cold start valve with the plug disconnected and remove the thermotime circuit from the equation altogether.

I left the fuel line connected and had previously pressurized the fuel line. I used 2 jumpers and grounded one side of the CSV and hooked the other to the coil with the key on. The CSV made a loud click.

(I was very careful about sparks)

I expected gas to be expelled. Nothing came out. Was my theory wrong or is my CSV is bad?

Give us some details about your rig. May help some.

Pressurized line keeps it's pressure? How did you test this?

Can you do your open the valve test with the fuel pump running?

Here, rest your head on this pillow....

Now, tell us why you are chasing cold start valve issues.



Oh, and welcome.

Gypsie wrote:Give us some details about your rig. May help some.

Pressurized line keeps it's pressure? How did you test this?

Can you do your open the valve test with the fuel pump running?

Here, rest your head on this pillow....

Now, tell us why you are chasing cold start valve issues.



Oh, and welcome.

Thanks.

I'm working through a methodical test of my entire FI system (78 Super Beetle) due to hard start problems and a secondary severe exhaust heat problem when it does start. I'm trying to isolate all the variables so only the ones that are questionable remain.

My CSV doesn't leak and the temp is in the 70's so it should be a non-factor but I want to test it all the same to be certain it's working properly.

I verified in an earlier fuel pressure test that the line remains pressurized. Also when I removed a fuel line, I took a shot of fuel right in the eyes. So it's definately pressurized.

I could do the test with the fuel pump running. Pressurized gas and electrical jumpers make me nervous so I chose to rely on existing fuel pressure. Previous fuel pressure tests show the rail has pressure of 38 psi and it holds 38psi after then key is turned off.

So the basic question is: shouldn't this direct jumpering of the CSV cause it to open and assuming there is fuel pressure, squirt gas.

got_the_bug wrote:I expected gas to be expelled. Nothing came out. Was my theory wrong or is my CSV is bad?

It sounds like you've done everything correctly. It even sounds like your CSV is working (the click), but perhaps is plugged up? Maybe you can remove it and spray some carb/injector cleaner in it to see if you can clean out whatever might be obstructing the flow.

Oh, and X2 on the welcome!

Perhaps I could try soaking it in mineral spirits.

On the other hand maybe I should just leave it alone since it's not leaking and I don't intend to drive it in cold weather. Would be a shame if I unplug it and it leaks. Darn things cost $150 new.

You need a cold start injector even in warmish weather when the engine is cold. Just not for very long.

Your fuel line holds pressure, but how is the flow? Have you done the flow test to see that your fuel delivery system is in good order?

vwlover77 wrote:You need a cold start injector even in warmish weather when the engine is cold. Just not for very long.

Your fuel line holds pressure, but how is the flow? Have you done the flow test to see that your fuel delivery system is in good order?

Well now that's new information. I wondered about that but everything I've read says 55 degrees was the starting point for "cold".

Fuel flow is fine thru the main line supplying the rail. Never tested flow thru the rail itself other than to see the injectors spray which they do.