Bad PCV? Idle issue

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roccodart440

roccodart440

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Car has done something odd randomly several times this year but yesterday the issue stayed and almost left me stranded.

It's a 440, 950 proform.

Drive it down the road it runs perfect. I come to a light and it acts like it will stall. Throttle it lightly and it would improve and go away.

Yesterday it actually stalled and acted almost flooded on re-start. When it would almost stall it seemed like maybe a vacuum leak. I checked PCV since it's the only vacuum port/line being used. If I plugged it would drag the idle down. If I unplugged it the idle would go up to like 1100. I shook it and it rattled a lot but when I tried to breath through it acted funny. Went and bought a new one and they sound and work different.

I also noticed that lately my warmup time has decreased and it smells rich when backing out of the garage.

Tonight I'll try the new PCV and see what happens.

I was wondering what your guys take on these symptoms are.
 
Sounds like an overflow problem or high fuel level to me. (like a bad or contaminated needle or seat maybe) cause you said it feels richer and takes less warmup time.

Gotta watch a new PCV valve because I got one that was wide open and didn't close when it was supposed to, and it was sucking so much vacuum it was pulling oil mist out of the motor causing it to smoke like a pig at stoplights. (it was mis assembled or something) and another one fixed it.

Idling down with it plugged is normal just so you know.

You have an overfueling problem there somwhere.
 
I looked at the fuel bowl sight glasses. They are half way up the window.
 
roccodart440 said:
I looked at the fuel bowl sight glasses. They are half way up the window.
Click to expand...

There HAS to be something causing overfueling there.

One thing you could try that I do if I think I may have an overfuel problem is to stop the fuel supply to the carb while it's running and see if it smooths out as the fuel in the carb gets lower.

Any chance you can try this with your fuel system?

(Disconnect an electric pump temporarily, or pinch a rubber line maybe?)

I'll tell you what you need to know REAL fast.
 
TrailBeast said:
There HAS to be something causing overfueling there.

One thing you could try that I do if I think I may have an overfuel problem is to stop the fuel supply to the carb while it's running and see if it smooths out as the fuel in the carb gets lower.

Any chance you can try this with your fuel system?

(Disconnect an electric pump temporarily, or pinch a rubber line maybe?)

I'll tell you what you need to know REAL fast.
Click to expand...



My electric pump is on a manual switch.

If the PCV doesn't cure this problem. Tell me exactly the test you want me to do.
 
roccodart440 said:
My electric pump is on a manual switch.

If the PCV doesn't cure this problem. Tell me exactly the test you want me to do.
Click to expand...

Run it and turn off the fuel pump to see if it smoothes out after 15 30 seconds of running.
If it does smooth out and run nicer it's over fueling for some reason.

Try that and see what it does.
 
just for the heck of it, spray some carb cleaner on all the air bleeds
 
Have you checked the fuel pressure? You said that you're running an electric pump so I'm guessing that you have a regulator also. There could be a problem with the regulator and it's sending too much pressure to the carb.

Ted
 
DusTed74 said:
Have you checked the fuel pressure? You said that you're running an electric pump so I'm guessing that you have a regulator also. There could be a problem with the regulator and it's sending too much pressure to the carb.

Ted
Click to expand...

It has a regulator. Fuel pressure gauge isn't working anymore.
 
Cutting the fuel supply and seeing how it acts about it will point out any of these problems.
Then being sure if it's an over fuel or under fuel problem will tell us where to go from there.

But yes, all the above are possible.
 
abody said:
just for the heck of it, spray some carb cleaner on all the air bleeds
Click to expand...

When it's running or when it's off? And what are we trying to accomplish with this?



furyus2 said:
Look for fuel dripping in the carb when idling.
Click to expand...

It isn't. butterfly's are dry and no fuel leaking.



DusTed74 said:
Have you checked the fuel pressure? You said that you're running an electric pump so I'm guessing that you have a regulator also. There could be a problem with the regulator and it's sending too much pressure to the carb.

Ted
Click to expand...

No issue with float level. Haven't changed anything with regulator.



TrailBeast said:
Cutting the fuel supply and seeing how it acts about it will point out any of these problems.
Then being sure if it's an over fuel or under fuel problem will tell us where to go from there.

But yes, all the above are possible.
Click to expand...

Ok, trail beast. I started it last night and warmed it up to about 130-140 deg. It is running fat, like burn your eyes and stink. I cut fuel pump for 30 seconds, I could watch the fuel level in the bowls drop but nothing changed with how it ran.


hangn0ut said:
Is that picture your carb? Because those butterflies look wet to me.
Click to expand...

No, it was a online pic I found. I just wanted to make sure where the one guy wanted me to spray the carb cleaner.
 
I'm bringing the carb to my engine builder tonight. He's going to clean it and check the PV.
 
roccodart440 said:
I'm bringing the carb to my engine builder tonight. He's going to clean it and check the PV.
Click to expand...

Not a bad idea at all.
That's strange that cutting the fuel didn't change anything if it was running so rich, so it may very well be the power valve.
 
TrailBeast said:
Not a bad idea at all.
That's strange that cutting the fuel didn't change anything if it was running so rich, so it may very well be the power valve.
Click to expand...

Well it wasn't dripping into the carb and the float levels looked good.

The only other thing I can think of is to turn the idle air bleed screw all the way in. If it still idles the fuel must be coming from somewhere
 
Replaced the PCV and fuel filter just for insurance. I also ordered a new fuel pressure gauge.

Took the carb to my engine builder and he blew it all out and said it looked good with one exception, the base plate was loose. He took the screws out of it with the tips of his fingers. Put them back in and re-torqued with Loctite.

I'm taking it to a cruise-in tonight. We shall see....
 
The car did well last night. I think the idle could be bumped up just a tad and have idle bleeds gone back over once but all seems to be well now.
 
roccodart440 said:
The car did well last night. I think the idle could be bumped up just a tad and have idle bleeds gone back over once but all seems to be well now.
Click to expand...

Glad you got it, and now it makes sense why it was getting to much fuel even when you shut off the pump.
If you would have cut the fuel until it died it would have smoothed out right before it quit, but I don't think I would have thought of the base being loose causing it.
 
I just had a thought. With the loose base plate the PV could lose some vacuum signal, which would allow the spring to open the fuel-port, which would set the boosters to dribbling. does that sound about right? Cause if it is right, I want to try and remember that for future reference.
Cause kinda like TB says I dont think A loose base plate even entered my thoughts.I have only ever seen a loose plate once.Good catch, cause on some combos that center screw under a Holley, can drop right into the manifold.OUCH!
 
I can't take credit for finding the issue. My engine builder was tearing down the carb when he found all the screws were way loose.
 
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