Fuel into air cleaner assembly?

[woytovich]

Trying for a Thanksgiving Day 1st start on my new-to-me and not-started-in-20 years 240z.

I have it all fluid changed etc etc...

It cranks fine. It "starts" with starting fluid.

Problem: I have fuel to the carb area.... I know this because I am getting fuel flowing out of 2 ports into the air cleaner assembly... but ut's not starting.

I understand that I might still have electrical/ignition issues. I istalled a Pertronix unit and do not KNOW that it is working properly. But my concern at the moment is this fuel issue.

What's going on here?

THANKS,

Mark

[Zs-ondabrain]

The Float bowl valves need to be UNSTUCK. After a period of time, with no fuel in the float bowls, the valves stick or rust open. Therefore, your floats can't stop the flow of fuel and it spills out the top of the float bowl, thru the hose and into air-cleaner assembly.

The car won't start cause the needed fuel is going elsewhere and the bowls probably have crap in the bottom, plugging the fuel nozzle hose that runs from the float bowls to the bottom of the carbs.

So tear into the bowls, clean them out. Pulle the valve using a 10mm wrench. Remove the inner valve from the valve body, clean it and make sure it operates properly before reinstalling it. Try not to mess with the metal tab on the black float that touches the valve. As that tab is your float adjustment tab, to stop the fuel at a certain level.

Happy Turkey Day.

Dave

Edited November 26, 2009 by Zs-ondabrain

[woytovich]

Thank you... that was one of the random thoughts that crossed my turkey-deprived mind.

I'll look for that info in the FSM as a guide (gotta love the FSMs)

Thank you, happy thanksgiving!

Mark

[woytovich]

Ok... so here's what I found:

goop in the little hoses that run from the bottom of the fuel bowl up to the rest of the carb. Cleaned it all out with carb cleaner...

I still can't get it to run. I took the top off the carbs, cleaned the jet needle and hole and sides of the suction piston... the lifter now moves freely.

It will "run" with starter fluid, so I know I have spark.

I don't think I have fuel coming up into the air/fuel chamber... even if I manually push the lifter while cranking. (There is fuel in the float chamber.)

What am I missing?

Mark

[Zs-ondabrain]

The next thing you need to clean is the Banjo filter. The banjo is the inlet tube on top of the float bowls. Pull the big (17mm or 19mm) bolt holding the banjo to the top and slowly pull the bolt and the small filter in there. Clean everything with carb cleaner, (the banjo neck, screen filter, inlet to the floats, the hose that connects the float bowls to the fuel rail on the Valve cover, the fuel rail (blow it out)-after removing the hoses on the other end near the pump and return line.

This will all be a neccesary evil in the proper flow of fuel. There's obviously an obstruction of some sort and you might as well cover all your basis. New fuel filter helps too.

Dave

[MikeW]

If there truly is fuel in the float chambers then you've narrowed down the problem considerably. Usually it's a clogged filter or fuel line or banjo filter where the fuel comes into the float bowl. It's possible that the small fuel hoses you mentioned are still a problem even after cleaning. You can get new hoses from ztherapy.com.

When you said changed all fluids I assume you have fresh fuel as well. Stale gas can definitely cause it to not run.

[woytovich]

Have a new fuel filter. gas is new although there was some old fuel in the system that still seems to be tainting the gas (from the color and smell anyway). I will clean the banjo filter and see where that leaves me... I'll replace fuel line too... Can I use parts store fuel line or are these some proprietary sizes?

Edited November 28, 2009 by woytovich

[woytovich]

What is the mechanism behind the "suction piston"? Where does it get the suction? Is it possible that this is causing a problem for me here? (lack of proper vacuum?) Is there a seal or gasket or something I should be looking at?

It still does not want to run even if I hold up the piston with the manual lifter....

Mark

[MikeW]

The vacuum is generated directly by the effect of a dropping engine piston sucking air through the intake manifold and therefore through the carb. Here's one explanation:

http://www.zparts.com/zptech/articles/mal_land/ml_sucarb2/SUcarb_111601b.htm

[Zs-ondabrain]

Also, by holding that piston up with the "Test Pin", you're over choking the engine. You're cutting your fuel to air ratio. WAY too much air and not enough fuel.

Choke the hell out of it using the choke. And leave the piston alone. That's obviously Not helping.

Dave