Help - 440 wont idle

[Kerplunk]

Hey guys,

Im chasing my tail on this one, and starting to think Im going backwards in stead of forwards...

So I started my 67 belvedere - (440 auto, holley 3310) a few weeks ago, and it ran a bit rough, took it down the road and it felt like it was a missing a bit, put my foot a bit into it and got a nice gunshot backfire, found that I had two plug wires reversed, fixed that but now its difficult to get it to idle.

It now feels like its popping and missing through the exhaust. I pulled the plugs and they were black, and there is a lot of fuel getting into the oil, I thought I had ruptured the fuel pump diaphram but I replaced it with a spare and its still the same. The other noticable difference is its blowing grey smoke that will make your eyes but out the exhaust.

this is what Ive checked so far.

- replaced the power valve
- replaced the plugs
- checked timing
- double checked the firing order
- checked float levels
- the secondary needle and seat had some debris stuck in it, cleaned that out but no change

a friend suggested a burnt or sticking valve, so Im guessing the next step is a compression test.

Anyone have any suggestions, Im starting to feel as though the car hates me LOL
Thanks!

 

[RustyRatRod]

While it's "running" slowly close the choke by hand. If it starts to run better, you have a vacuum leak somewhere. Does it have power brakes? The power brake circuit is really notorious for leaking. Check from there the hose connects to the engine ALL the way up to the booster. You can also get a spray bottle of water and spray all around the carburetor and intake to check for vacuum leaks. DON'T use carburetor cleaner or anything flammable.

 

[Kerplunk]

Thanks Rusty, the brakes are non power,
I forgot to mention if I cover the air horn with my hand it doesn't change how it runs, I would have thought it would have choked the motor but no change.
Ill look for a vacuum leak...

 

[bm02tj]

check if metering block is straight or you will get vacuum leak and keep power valve open
they are easy to straighten

check points condenser and coil for function

good luck

 

[D575]

Give it more timing.

 

[benno440]

throw a hammer at it, generally behaves then

 

[Bigal75]

Have you tried to lean out the carb? Is the 3310 the vacuum secondary 750? I had one on my truck - I wasn't a real fan.

 

[Kerplunk]

yeah Bigal its a 750 holley, Im not becoming the biggest fan of the 3310 either, and i think it may come down to Benno's suggestion. LOL

I did a compression test and I think it came out OK, I know your supposed to do it warm, but i can hardly get my fat mitts into reach the spark plugs when its cold, so damn near impossible with hot exhaust manifolds.
Here are the numbers...

1 - 150
2 - 155
3 - 145
4 - 155
5 - 150
6 - 165
7 - 155
8 - 160

So I'm thinking vacuum leak is the next step.

 

[62MAX]

Thanks Rusty, the brakes are non power,
I forgot to mention if I cover the air horn with my hand it doesn't change how it runs, I would have thought it would have choked the motor but no change.
Ill look for a vacuum leak...

If closing off the air horn doesn't have any affect,you have a vacuum leak somewhere.

 

[TRAMO]

Mine did similar and it was the front needle/seat oring broke

 

[Kerplunk]

UPDATE - so shes fixed now, apparently when I went to the local speed shop for a new power valve and metering block gasket, they gave me the wrong gasket. so it was just dumping in fuel.
Thanks guys for all the replies.

 

[bm02tj]

I save all the old gaskets and compare with new ones and then chuck them as most kits have extra parts so I sort first

good to hear you got it fixed

 

[rsd859]

I had the same problem once, glad you got it fixed.