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Rough Idle / Poor Mileage
https://www.slantsix.org/forum/viewtopic.php?t=10833		 Page 1 of 1
Author:  70survivor [ Sat Nov 06, 2004 6:43 pm ]
Post subject:  Rough Idle / Poor Mileage
I recently rebuilt my /6 in a 70 Valiant. I replaced the points with EI and put a Carter BBD from a 318 on it. I'm having some problems with rough idling and it seems a bit sluggish from a dead stop when I nail it. I have the timing set at 8 BTDC and have replaced the vacuum pod on the distributor. The car is also eating my lunch in gas. The plugs are showing signs that it's running rich also. If I nail it and then let off quickly, it acts like it wants to die but then picks back up. Would a vacuum leak around the throttle shaft cause these problems? Is the 318 BBD too much for it to handle? I have the original BBD from the SUper 6 setup that I have yet to rebuild. What about replacing the coil with something hotter? It just has a stock coil on it now but I have not checked the primary and secondary resistance values yet.
Author:  k9wkj [ Sat Nov 06, 2004 7:14 pm ]
Post subject: 
sounds like the float has submarined
those things like to do that
could be a float level thing
remember you changed the angle the carb sits at
if it was close to to high then it would be
Author:  GunPilot [ Sat Nov 06, 2004 10:03 pm ]
Post subject: 
What is your total timing at cruise? Do you have your vacuum advance hooked up?
Author:  Doctor Dodge [ Sun Nov 07, 2004 2:44 am ]
Post subject: 
Does the timing mark move as you rev up the engine?
Have you checked your valve adjustment recently?
What happens when you plug the PCV valve?
DD
Author:  70survivor [ Sun Nov 07, 2004 4:53 pm ]
Post subject: 
After replacing the vacuum pod, I hooked up my vacuum pump and noticed a that the timing mark did advance as I increased vacuum. It acts a little better from a dead stop now so I am assuming that it is now advancing properly. However, I have not checked my total advance at cruise. I have not adjusted the valves lately, so I'll try doing the running adjustment this week. Is there anything special I need to know before doing a running adjustment? I'll also check the PCV valve but I have also recently replaced it. What should it do when it is plugged?

What about using a hotter coil? Will that help my mileage? Which one should I use?
Author:  sixty4dartgt [ Sun Nov 07, 2004 11:14 pm ]
Post subject: 
If you are going to use a 3/8 socket to adjust the valves, I would tape it to the extention. Those valves going up and down can knock it off and you don't want it falling down inside the motor. :shock:
Author:  70survivor [ Wed Nov 10, 2004 5:56 pm ]
Post subject:  Now What?
I'm obviously doing something wrong or I've got a problem I just can't find. I adjusted the valves with the engine running and was able to quiet down some of the clatter. That did not help my idle problem. I plugged the PCV valve and the RPM increased for a moment and then settled back down. It acts like a vacuum leak but I can't find it either. Any more ideas??? I've got another carb I'm going to put on it to see if it makes a difference. :cry:
Author:  Joug_Fin [ Thu Nov 11, 2004 9:00 am ]
Post subject: 
Check distributor cap contacts. If they are dirty it helps a lot if you clean them.
Author:  Doctor Dodge [ Fri Nov 12, 2004 9:06 am ]
Post subject: 
One test is to cover the carb's throat during rough idle to see if the idle condition improves. (slowly close the carb flap is the way I do the test, you may have to back-off / disconnect the fast idle screw/cam)

If you can get the idle to improve by choking down the idle air flow, you have a lean idle condition caused by a vacuum leak or a clogged / lean idle circuit in the carb.

Have you done a compression test, are all cylinders even on compression?
DD
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