Rough Cold Idle

[crj1968]

Hello...just throwing this out for any input- thanks

Mild 440, has a performer RPM and had a Holley 670CFM (elec choke) on it and single point distributor. Had hesistation issues

I put on a Edelbrock 750 (elec choke) that I had and the hesistation issue is nearly eliminated.

I then put in a pertronix flamethrower distributor.  @ 15 degrees BTC (hard to know exactly)

Anyway car seems to run pretty dang good and better than ever EXCEPT now when I initially start it up it is rough- like barely hanging on. But it does fire right up when cold.  It's really crappy like it is missing or running on 3 cyls. I can see the choke opening and it still runs crappy. Then it just suddenly sort of warms up and runs like a top.   

I gotta think this is an issue with the carb? Unfortunately, I didn't run it very long with the new carb before throwing in the elec ignition, so uh......

If I let it sit for an hour an hour or two and fire it up it is good to go.

[Just 6T9 CHGR]

Sounds like the choke not opening fast enough? 

[crj1968]

Yeah- I was thinking the choke also, so I removed the air cleaner and with the hood up I can see the choke open up and it still runs bad.

[cudaken]

Then it is opening to fast? 

[crj1968]

Well I went out to check it out and try and get more info, and it started and ran perfectly. 

    

(just thought I'd use that emoticon, because no one else ever does) 

[Dino]

My car did the exact same thing with the eddy 1407.  I got tired of trying to dial that thing in as it always ran rich at idle and lean at wot.  I finally gave in and rebuilt the thermoquad that came with the car.  All issues are gone and the car drives like it was brand new.

If you want to keep that carb I suggest getting the tuning kit for it.

[crj1968]

hmmmmmmm, I do like me some thermoquad.   

[Dino]

hmmmmmmm, I do like me some thermoquad.   

I will never look back.  The only fuel system that will replace my TQ is sequential EFI.  I cruise my car mostly so the small primaries are perfect for crisp throttle response around town.  And the big secondaries really make the car go when you punch it.  Hard to beat imo.

[c00nhunterjoe]

Imo ditching the holley for an edlebrock was the first problem. Holleys are not hard to tune and once done, they are incredible. A 670 on a 440 will not make optimum power but jetted and tuned should be EXTREMELY responsive.

[cudaken]

hmmmmmmm, I do like me some thermoquad.   

When they work right, I loved them but that can be said of all carbs. Long, long, long, long time ago my 750 Holley on my 68 Road Runner gave up it ghost. (still have the 68 Road Runner) Friend loaned me a Thermoquad with the adapter plate. 383 had 284 Hemi Cam, Torker intake, headers and such. It really woke up the bottom end of the power band! Lost a little power on the top end, but below 4900 RPM's!  I hated giving it back.

Cuda Ken