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Old 05-09-2018, 07:10 AM
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The weights in the hei can change your idle like that if they’re sticking.
Or a light a set of springs won’t pull them back all the way.

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Old 05-09-2018, 08:43 AM
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Checked your plugs? Fouled plugs will give those symptoms...

Russ
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Old 05-09-2018, 09:35 AM
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Quote:
Originally Posted by RWENUTS View Post
The weights in the hei can change your idle like that if they’re sticking.
Or a light a set of springs won’t pull them back all the way.
I do have lighter springs in the dizzy to make it advance earlier, i'll try a little wd40 on the weights to see if that helps.


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Originally Posted by S10xGN View Post
Checked your plugs? Fouled plugs will give those symptoms...

Russ
I just changed the plugs only a couple of weeks ago, with a fresh set of NGK platinum tips. I'll pull them this weekend and have a look.
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Old 05-09-2018, 05:40 PM
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another caveat to that are the springs themselves. Examine them to make sure they are not bent/stretched..
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Old 05-09-2018, 05:44 PM
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Quote:
Originally Posted by 396caprice View Post
I suppose it's possible, I've heard of loose exhaust connections letting fresh air in that can cause popping. Would fresh air in the exhaust make the engine stumble too?
muffler to exhaust manifold/header is a long shot, but thought i'd mention it considering all the other ideas that'd been thrown your way. Did not know you had a stumble problem...that being said, a loose muffler connection to flange should not give you a stumble in motor problem. sorry just now responding, been off for a few days.
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Old 05-09-2018, 09:48 PM
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Quote:
Originally Posted by rdobbs77 View Post
muffler to exhaust manifold/header is a long shot, but thought i'd mention it considering all the other ideas that'd been thrown your way. Did not know you had a stumble problem...that being said, a loose muffler connection to flange should not give you a stumble in motor problem. sorry just now responding, been off for a few days.
No problem, yeah I plan on giving the dizzy an inspection on the weekend, taking everything apart, minus pulling it from the motor. I'll be checking the springs/weights checking for excess shaft play and testing the electronics.
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Old 05-11-2018, 11:05 PM
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Anybody have issue's with vacuum advances going bad, what are some symptoms of a bad advance??
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Old 05-13-2018, 07:47 AM
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Vacuum advance pods can go bad over time but the symptoms I assume since I have one yet to go bad but have read of them going bad is you would just not have any vacuum advance timing and it would affect things to a point mainly at idle if your running it off of full manifold as with the loss of extra timing at idle your idle rpm would drop a few hundred rpm give or take a hair depending on your timing curve etc and engine build.

I can't say for sure but if the diaphragm would go bad and rupture I assume it could cause a very tiny vacuum leak if the pod is not airtight inside but maybe I am over thinking on that one. Best way to check it is with a timing light and use a vacuum pump and pump the pod with some vacuum from your pump and look at your timing light and see if it advances like it should.
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Old 05-15-2018, 10:29 PM
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UPDATE. One problem solved, now a new one has suddenly arisen.

So finally found the culprit for the rough random idle. As it turns out one of the metering rods in the Street Demon I was using, was stuck open and letting fuel dump into the motor. Replaced the Demon with a 600 cfm Edelbrock performer and problem solved.

Now however, the car backfires under load and has now power under hard acceleration. I've verified the timing (again) and cant seem to figure it out. The car idles smooth and revs fine in park, perhaps something in the Valvetrain?
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Old 05-16-2018, 05:49 AM
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What edelbrock 600 do you have? There is one that is calibrated really lean out of the box compared to the other one which is calibrated more for performance setting wise but I can't remember the part numbers right off hand. If your timing and stuff is good then you might need to change your pump shot as if its giving a back fire when you give it throttle under load that would be the first thing to check and if it has no power under acceleration then you might need to give it a step up in the fuel curve by changing either the jets or metering rods.

The best thing is to have a kit so you can have the different metering rods and jets so you can truly dial the carb in and have it to where it needs to be. I would look at your manual and see where it is set at for power cruise and go one step richer and see how it does.
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Old 05-16-2018, 06:40 AM
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You likely need a regulator for that new eddy carb.
They don’t like more than 5 psi. Maybe even a little less at your elevation.
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Old 05-16-2018, 10:27 PM
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Quote:
Originally Posted by eric32 View Post
What edelbrock 600 do you have? There is one that is calibrated really lean out of the box compared to the other one which is calibrated more for performance setting wise but I can't remember the part numbers right off hand. If your timing and stuff is good then you might need to change your pump shot as if its giving a back fire when you give it throttle under load that would be the first thing to check and if it has no power under acceleration then you might need to give it a step up in the fuel curve by changing either the jets or metering rods.

The best thing is to have a kit so you can have the different metering rods and jets so you can truly dial the carb in and have it to where it needs to be. I would look at your manual and see where it is set at for power cruise and go one step richer and see how it does.
Carb is an old 1405 that was sitting for the past 15 years. I've rebuilt it and added an electric choke. It was previously being used on a stock 327 with double hump heads and an RV cam, with very good results. I should clarify that the bucking/stumble under load had previously started a few days ago when the car was still using the Street Demon carb.
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Old 05-25-2018, 09:12 PM
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FIXED!!!

ended up being a badly worn dizzy shaft, throwing the timing off and causing the car to run like crap. Stabbed in a brand new oem unit and the problem is gone.
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Old 05-26-2018, 07:21 AM
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Glad you got it fixed.
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