rough running....backfiring 350

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Ricko1966

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Ken B said:
Rikko,
If you can see that vacumn line I USED to have....thats where is should land on the carb from the distributor correct?
vacuum hose has blue painters tape on it
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That's ported Don't mess with vacuum lines or distributor yet. 1 thing at a time,checkbthe firing order. Then we can move to the next thing. When you start messing with multiple things you sometimes confuse the issue. Whoever disconnected your vacuum advance did not do you any favors. That is load based advance,it's like a primitive map sensor and ecm. It gives additional advance in lean light load situations when you need it. Step on the throttle for power the vaccum drops,the additional advance goes away. Disconnecting it does nothing at all for power,but ensures you don't have it when your engine needs it. You'll take a big hit on mpg,also engine cooling,plug life.
 
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Ken B

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So I have not touched any plug wires except to label them ( see pics) . I think since Lego pointed out my labeling error I think everything matches now....
 
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So 1st thing I did was confirm the wires/firing order is correct. I believe it is correct.
I just replaced the vacuum hose from the distributor to the carb. Big improvement. Still got a cough/backfire occasionally.
Possible fouled plugs since the vacuum advance wasnt "breathing"?
I am trying to get a good smooth running 350 nothing crazy. But is still has more to be diagnosed.
 
Ken B

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The information I have been. Given on here has been huge .
 
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Back fires are usually ignition. If you are sure all the wires are on the right terminals and routed to the correct plugs try bumping the timing a few degree see if that helps.. mark the distributor base and the the manifold,with a punch,paint dots whatever,so you know where you were.Rotate the distributor, 1/16 of a turn counter clockwise using your punch marks as reference. Just eye ball for 1/16. That would be 10 degrees if it runs good there,give it a little more if it pings or runs worse back it down.for what it's worth 1/16th would be 10 crankshaft degrees.
 
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Ken B

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Thanks.
I drove around the neighborhood and it was much improved.
But still has a ways to go to get where it should be.
 
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Ken B said:
Thanks.
I drove around the neighborhood and it was much improved.
But still has a ways to go to get where it should be.
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Did you twist the distributor?
 
Ken B

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no i am sorry i was refering to earlier drive....i will try the distributor tomorrow.
 
Ken B

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i just need to learn more about all of the connections on the carb. there are more ports that are just plugged off ....i just dunno why.....
 
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Here is another question.....
The vacuum line from the distributor....it is hooked up to what shows in the 2nd pic to the EGR port (labeled C) and not to distributor vacuum port ( labeled F).
Am i safe to assume this is incorrect as well???

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Ken B said:
Here is another question.....
The vacuum line from the distributor....it is hooked up to what shows in the 2nd pic to the EGR port (labeled C) and not to distributor vacuum port ( labeled F).
Am i safe to assume this is incorrect as well???

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Post #19 yes you should have vacuum advance on F not ported vacuum.
 
Ken B

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Thank you Sir.
So that leaves the EGR port open, ok to cap that or where SHOULD it go?
 
Ken B

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I certainly appreciate all the help. Just to get closer to where things are supposed to be.
I have not changed timing I just tried to land tubing where it is supposed to go.
 
Ken B

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still rough running with just the carb lines moved/replaced.
 
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