A A Little Help? New 440 Runs Rough, Won't Idle

[rlem1977]

Need to set timing with a vacuum gauge. Not sure what model Holley you have, but follow Holley's instructions for idle adjustment. Also, sounds like distributor may be off a tooth. Read the Holley instructions! Once running, check for vacuum leaks around carb base and intake; intake and heads.

 

[mopar 3 B]

Have you stopped payment yet? Or are you still believing the dino tune crap?
Have you checked the Holly power valve? Has it been fixed so a backfire will not take it out?
Add it to all others posted. Hope you find something before tareing it down.

 

[Garys1969RR]

Sounds like the engine may not be pulling enough vacuum to close the power valve. I would start by putting a power valve plug in the carb, primary and secondary too. May not have one in the secondary side.

 

[Garys1969RR]

Just noticed in the video that the choke is staying closed on the carb. Have someone hold it open, or put something on it to hold it open, then try to start it.

 

[AR67GTX]

If fuel pressure is getting as high as 9 psi that sounds high for a carburetor. Is this the same carb it was dyno'd with? Have you looked to see where the primary throttle plate rests at idle on the transition slot in the bores? Do you get any response when adjusting the idle mixture screws?

Any info on the above - basic carb tuning stuff on performance engines trying to get them to idle.

 

[moparnation74]

Engine was dyno tested at the machine shop before delivery. It’s all the way out in South Carolina so I was not present. I’m in CA.
Spark plugs are currently dark and smell like fuel.

Was it shipped without the distributor? Seems like your 180 off......

 

[451Mopar]

Looks like the choke is closing in the video?

 

[lewtot184]

i think it's slow timing. the carb can't be sorted out until the timing issue is solved.

 

[Garys1969RR]

Choke is definitely staying closed, causing it to bog down with gas. Also timing may be a little late. Maybe advance it 5 degrees, set it at 20 initial, 38 total. That's where most of them run the best.

 

[MoparViking70]

Thanks for all the advise guys. I’m hoping to make it back to the shop Tues.
Yes, the engine came with the distributor already installed, it does not seem to be a tooth off, pointed at cyl 1 on tdc compression.
The carburetor is supposedly the one they dyno’d it with.
I hadn’t considered the power valve thing and I thought a closed choke when cold starting an engine was a good thing. It’s a Quick Fuel 780cfm carburetor. I have already tried the curb idle adjustment from a half turn (out of the box) out to a turn and a half all round with no success.

 

[miller]

Yes, the engine came with the distributor already installed, it does not seem to be a tooth off, pointed at cyl 1 on tdc compression.

At TDC? That would be firing at 0 degrees. Is that what your saying?
If so, it's firing too late. Should be Before Top Dead Center...maybe 10-12 degrees.

 

[Garys1969RR]

An engine in good tune will usually need a choke to start easily. A new engine that is running rich, with the choke staying closed, needs more air to lean it out. Just begin by having someone hold the choke open to start it. At this point the plugs may be too black to fire a good spark. Getting the right mixture in there, neither too rich or too lean, is essential for starting. As are clean plugs. Just play with it a little, it sounds like it wants to start. I have even used a shot of starting fluid with a difficult engine sometimes, just to get it to start firing. Not too much, though.

 

[wyrmrider]

not with a high compression engine you can break rings
low compression smogger go for it

 

[mopar 3 B]

On any engine especially Desiel do not use starting fluid untill the engine is turning. Then use it sparingly.

 

[MoparViking70]

Thanks again for the advise guys. The no idle issue turned out to be really stupid. A big vacuum port that I had capped off on the back of the carb split the cap. Just a big vacuum leak. Feel free to punch me next time you see me.

 

[1967coronet440]

Let’s see a Video of that big block running smooth!

 

[MoparViking70]

Let’s see a Video of that big block running smooth!

 

[Garys1969RR]

That's great! No worries, we all have had minor glitches from time to time. I was using a Holley 780, with the auto choke mechanism removed. Car wouldn't hardly run off idle, bad flat spot. A carb guy checked it, and the choke pull off port on the side of carb where the choke was, that port was open all this time! Direct vacuum leak into the manifold! Plugged the 1/8th inch hole, and it ran great after that! Glad you got that thing running!