Carb not getting fuel with PCV attached

[Tgriffin91 27]

Hey all,

 

69 coupe. 302 w/o AC

 

I am having some trouble with my PCV set up. I have the PCV running from the carb spacer to the passanger cover. When I try to start the car it just tries to turn over endlessly. Pumping the gas does not put any into the carb.

I poured some gas in the carb and it will start but idles really really high.

Next I capped the PCV valve and the car starts right up. This leads me to believe it is not the fuel filters or pump. Has to be the PCV.

 

I do not understand how the PCV can prevent the carb from getting gas.

 

I can post some pictures later if that would help solve my issue.

 

Thanks!

[1969Fstback 58]

I am not an expert but it sounds like a vaccum issue to me. The advance on the distributer is vaccum driven. Unless you replaced it with a mechanical. Guessing you have a small leak and by capping the PCV line you redirect more to the distributor.

[j69302 11]

You are not supposed to hook the PCV valve up to the carb spacer. That will basically create a huge vacuum leak.

 

Hook it up to the port on the carb that is specifically designed for the PCV valve.

[bomccorkle 12]

what j said. and it should still try to catch and pumping the accelerator should also give you fuel the accel pump should send a noticable spray into the venturi

[Rcodenewf 44]

Actually on the 69 302 the pcv valve is hooked to the nipple on the carb spacer. My 69 fastback was totally original and the hose goes from the spacer to the valve cover.

 

John

[j69302 11]

The air going through the PCV valve has to be metered and accounted for by the carb or else it will create a vacuum leak. Plugging it into a manifold vacuum source such as a spacer, which are after the carbs have done their metering, will create a vacuum leak. Air would constantly be sucked into the driver side valve cover breather, through the crank case, to the PCV valve, and back into the intake manifold, bypassing the carb's metering system.

 

I didn't know that Ford installed carb spacers. And if that is the case, for it to work properly, it would have to be ported back into the carb somehow. That is why carbs have the PCV specific port. Are you sure its plugged into a SPACER? Autolite carbs have a specific PCV port on the back of the base plate, which would be just above a spacer if installed.

 

Even if you remove the PCV entirely, and plug the port, you will have to re adjust your carb. I did that on mine and plugging the port through the carb way off.

 

 

Tgriffin91 - can you give more details about your setup. Stock manifold? stock carb?

Are you sure the high idle was not caused by a choke? Will it continue to run on the fast idle, in other words, does it continue to get fuel once it runs after you spray gas down it.

 

Also, if possible, would like to see a picture of the spacer and port you have it plugged into.

 

And also, the PCV system has nothing to do with a carb getting or not getting enough fuel. It does however effect metering of the air/fuel ratio, which is why it will create a vacuum leak if the PCV is not hooked to the proper port.

 

If it IS hooked up correctly, then you may need to try and adjust your carb idle mixture screws to a baseline starting point.

 

For holly carbs, they recommend screwing the mixture screws in all the way, and back out 2 turns.

 

If it is not getting fuel to the carb, you need to look into the fuel system.

Edited July 3, 2013 by j69302

[69gmachine 15]

It does sound like a vacuum leak, but the PCV just uses manifold vacuum, it doesn't matter if it's in the base of the carb, a spacer under the carb or directly into the intake manifold. I have mine going directly into the manifold.

[Unkleen 11]

1970 boss 302 has a factory carb spacer, with PCV hose connected to it. Just sayin...

 

It sounds to me like the OP's PCV valve is stuck wide open, sucking just enough air from crankcase during start instead of drawing the fuel through carb. Remember - it is supposed to be closed during high vacuum (like starting/idling), and open during low vacuum. Change or clean the PCV valve and do a test from there.

[DocWok 30]

I agree with 69gmachine, a pcv valve just needs a manifold vacuum source, it doesn't matter where you pick it up from. Try swapping the pcv valve, they are supposed close at high vacuum levels (idle), yours may be stuck open.

[Tgriffin91 27]

Thank you guys for all your input. I'll look into the PCV valve. I think that is the cause after some more trouble shooting. Any recommendations as to good working ones. I got the one I have now from Oreilly. Guess they didn't give me a good one.

J69302- I have pretty much everything stock. Except I have added power steering. There is not a port on my Motocaft 2150 for the PCV that I know if. One for the break booster and one for the antistall dashpot. I think that is it.