72 240z won't start

[bg240]

My 72 had the same problem a few years ago. It had sat in the garage for about 6 months, had not been started, and no one had touched the car. I tried some of the things you did and it still did not start. My carbs have never been apart and I knew they were not out of adjustment. I do not consider myself a mechanic, so if I want to do the job myself, I have to keep it simple. Finally I tried something that is fairly easy and it worked. Disconnect the fuel lines going into each carb, not at the carbs, but up near the metal fuel lines. Get as much gas as possible out of the lines. I held a jar under each line. Very carelfully fill the lines back up with Gum Out or other carb cleaner. I used a spray can with the straw and pushed the button very gently. It will squirt out quickly so be careful of your eyes and your paint job. Put the lines back together without spilling the Gum Out out of the lines and then try to start. You may want to have a buddy spray some directly in the carb to get it started like you did before. My car ran after about 3 tries. The carb cleaner worked better when fed directly into the carb though the fuel line. Also, check your oil in your carbs. It tends to dry out when the car is not used.

[1972zed]

Originally Posted by 1972zed View Post

...snip...

- I took out the spark plug closest to the engine. ...snip

(meant to say took the spark plug out closest to the firewall)

[1972zed]

ok, I took both front and rear banjo bolts out and cleaned the sceen filters with carb cleaner. Cleaned the bolts too and sprayed carb cleaner in the holes.

- I then put it all back together no luck. Did not have the rear (closest to firewall) banjo bolt tight enuogh and had fuel leaking out. Took it off, and retightened it and no fuel seaping out. At least I know fuel is making it that far.

I then just for kicks took the bolt out of the front of the front float chamber.

I had a cup under the hole because I expected fuel to come gushing out. it did not. I sprayed some carb cleaner in and heard a hollow sound.

I then opened the rear float chamber (took the chamber cover off).

surprisingly there was not as much fuel in it as I expected. I thought it should be half full. although there was some fuel in it, I don't think there was more than a few milliliters max (or quarter inch) if that.

maybe the fuel pump? or a clogged hose somewhere? it seems wierd that both would act the same way. And there is fuel being pumped in.

I am going to take the front float chamber cover off tomorrow and have a look.

[1972zed]

by both I mean both carbs. Both have apparently empty float chambers. How full are these supposed to be anyway?

[WW2Winger]

The float adjustment is in the height of the float itself. There is a small tab that contacts the valve that can be slightly bent to adjust the action of the float. Adjusted to the correct level, the bowls are about half full as viewed upon removing the tops. At least that is my experience.

[1972zed]

...and since my float chambers are practically bone dry, thats my best clue yet. I will work back from there.

[MikeW]

Since it's highly unlikely that the transmission shop decided to adjust your floats I'd by inclined to think that the problem is a result of the car sitting for so long. One possibility is a cracked hose that is causing the fuel pump to suck air. I'd start by adding a clear fuel filter such as this:

http://performanceparts.com/part.php?partID=38377

It allows you to see that fuel is actually flowing from the pump and has the added benefit of letting you see if the filter is starting to get clogged from debris in the tank. If you find that you're not getting fuel into the filter then my next step would be to run a fuel hose from the suction side of the pump directly into a can of fuel.

[Ksteve]

If you are getting fuel to the banjo fittings but the bowls are not filling it is more than likely the needle valves are gummed up or clogged as JimmyZ mentioned earlier. These are the brass nozzel type fitting that screw into the underside of the float bowl covers. You can test it by taking the covers off and blowing into the fuel inlet tube on the banjo fitting. If you can't blow through them the needle valve needs to be removed and cleaned out.

Hope thats all it is as that would be a quick fix. Just be carefull not to break the float attachment tabs if you do remove the needle valves.

Steve

[1972zed]

I opened the front float cover, but couldnt get the cover all the way off. The float itself was interfering. There is a tab or something on the carb that I coudnt get clearance around.

Anyway I sprayed more carb cleaner into the float chamber and into the underside of the cover, and it started. Although running very rough now.

Im going to buy some carb cleaner gas additive and run it through the gasoline and see if that helps get the gum out.

oh and reset my points a little closer.