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1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks Discuss the Early Eighties Bullnose Ford Truck

1980 has stumble at idle, like butter in gear

 
  #16  
Old 02-11-2019, 10:07 PM
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Mark Your Calendar, I Was Less Correct Than Usual

Originally Posted by FuzzFace2 View Post
I am with DaveF, moving it 1 tooth will do nothing because you will have to re-align the distributor to get it back in time.
Do you guys ever get tired of being right?

Looks like I brought a knife to a gunfight. I broke out a spare distributor from my Pile-O-Partsô. No matter how I played with the darn thing, including making multiple paint marks and performing some pretty impressive angular calculations, it never did what I expected. I hang my head in shame...


 
  #17  
Old 02-12-2019, 03:02 AM
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Originally Posted by kr98664 View Post
Do you guys ever get tired of being right?

Looks like I brought a knife to a gunfight. I broke out a spare distributor from my Pile-O-Parts™. No matter how I played with the darn thing, including making multiple paint marks and performing some pretty impressive angular calculations, it never did what I expected. I hang my head in shame...
Maybe your protractor was broken and we are wrong ...................... no I don't think so
Some times we think it should work 1 way when we don't have enough coffee. after the 4 cup or so the light bulb goes off.
It's all good

Now I have seen posts about phasing the dist. and as many times I have gone over it I just dont get it but they say power can be had doing it.
I now wonder if it has to do with when the dist, sends the signal for spark and when the plug gets spark ie: cap is turned a degree or 2 from where it should be?
This could happen because the notch in the dist. is off a little then add the notch in the cap being off and the cap can be turned a little the rotor & cap could be off say 1* from when the dist. is firing.
I wonder
Dave ----
 
  #18  
Old 02-12-2019, 09:16 AM
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I drove it a few miles across town and back this morning just to get another overall feel.
Started right up cold without issue -tho I still feel the miss and curb idle even once warm is 1100 RPM; but again, once in gear the miss isnít noticed. Itís as smooth as glass at 550-600 RPM. My drive around town was fine, save the back fire when letting off gas suddenly or cresting a hill. Got home and put it in park and the RPM bounced back to 1100 (yes, I know thatís about 300 too high) and that miss is still there.
One thing I was thinking about when I saw the miss with the timing light the other night it wasnít like there was a hole in the spark patern but rather an extra spark where there shouldnít have been -I observed this only on the #1 cylinder
 
  #19  
Old 02-12-2019, 10:47 AM
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I knnow it's dumb but one time I set my ignition timing wrong by 3 degrees because I read the dash marks wrong on the harmonic balancer. Those dashes can be difficult to interpret especially with any crud on them. I ran it like that for a long time and went thru a lot of trouble shooting before I figured it out... probly not the case here but thought it might be worth a check
 
  #20  
Old 02-12-2019, 12:09 PM
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I had time to tinker this morning and hereís what I found. -I think It was Fuzz who told me to check my bowl levels. And they werenít spewing gas out but enough that there was some adjustment. Done ✅. (I can rev it up with no back fire) Next went over to curb idle and brought it down to around 850; but found I could actually go as low as 500 and it still sounded strong. But I stuck with 850. Next I made sure air mix was good and achieved 16-18 lbs vac. Good as it gets....drops to 13 in gear at 500 RPM.
Next put my hand on the dizzy cap, moved it left and sounded like crap, twisted right and RPMs picked up and smoothed out. In theory this tells me maybe the dist. would be better turned slightly left.... wrong. Once advance is unplugged I can bounce the cap left to right ***** Nilly and it doesnít play a difference one bit. For grins I did turn the timing down and noticed stumble, drop in vac, etc, turned it back up as high as 25 (Up and down is a relative term here) and engine sounded smoother and vacuum came up. I set it at 20 and came in - Iím stumped especially since my miss is still there at idle...
I made a slow mo video that may explain it tho! Check at :46 & 2:08; thereís an extra spark pulse!
 
  #21  
Old 02-12-2019, 03:46 PM
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I don't think that is an extra pulse but a weak one, the miss.
We need to find where that spark is going.
Does this happen to the other wires / plugs?
Have you popped off the dist. cap to look it and the rotor over to see what they look like?
Any rust dust marks or oily film inside? Does the PCV work?

Also when off look at the notch in the cap & adaptor then pop off the adaptor and check the notch in it and the dist.
There has to be a reason why the cap moves around so much.

Pull the coil wire from the coil & cap and check the wire ends and the cap / coil parts for corrosion.
I would also check all the other wires and cap for corrosion.
If you change the cap & rotor just make sure you check the wire ends.


Then check the other wires to the coil to make sure they are in good shape, clean & tight.
Pull apart the 2 plugs to the IGN box and make sure they do not have corrosion.
Dave ----
 
  #22  
Old 02-12-2019, 04:28 PM
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The cap sits on the adapter just fine, notch lines up and itís tight. The adapter feel sloppy to me -this is why Iím concerned with being able to move it around and I wonder if that would cause the miss.

 
  #23  
Old 02-12-2019, 05:21 PM
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On the cap where your thumb is it looks damp / moist is it?
I would spray it out with cab or brake cleaner even starting fluid and let it dry really good before putting it back on.
On the rotor just to the right and lower from your thumb looks like a crack, is it?
I am not a fan of the clear cab or rotor, blue or black for both for me.

Have you pulled the wires out of the cap yet to check them?
Dave ----
 
  #24  
Old 02-12-2019, 05:50 PM
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Originally Posted by FuzzFace2 View Post
On the cap where your thumb is it looks damp / moist is it?
I would spray it out with cab or brake cleaner even starting fluid and let it dry really good before putting it back on.
On the rotor just to the right and lower from your thumb looks like a crack, is it?
I am not a fan of the clear cab or rotor, blue or black for both for me.

Have you pulled the wires out of the cap yet to check them?
Dave ----
rotor is in in good shape and must just be the light on the cap. -itís bone dry. I did use a little emery cloth just to knock the dull off the rotor and cleaned it with brake cleaner before installing. My idle is still creeping up to high and I think itís just the throttle not fully returning, so I may at a spring and perch. Iíll go get a new adapter tomorrow and see if that makes a bit of difference
 
  #25  
Old 02-12-2019, 07:30 PM
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Originally Posted by Xwarrior86 View Post
I had time to tinker this morning and here’s what I found. -I think It was Fuzz who told me to check my bowl levels. And they weren’t spewing gas out but enough that there was some adjustment. Done ✅. (I can rev it up with no back fire) Next went over to curb idle and brought it down to around 850; but found I could actually go as low as 500 and it still sounded strong. But I stuck with 850. Next I made sure air mix was good and achieved 16-18 lbs vac. Good as it gets....drops to 13 in gear at 500 RPM.
Next put my hand on the dizzy cap, moved it left and sounded like crap, twisted right and RPMs picked up and smoothed out. In theory this tells me maybe the dist. would be better turned slightly left.... wrong. Once advance is unplugged I can bounce the cap left to right ***** Nilly and it doesn’t play a difference one bit. For grins I did turn the timing down and noticed stumble, drop in vac, etc, turned it back up as high as 25 (Up and down is a relative term here) and engine sounded smoother and vacuum came up. I set it at 20 and came in - I’m stumped especially since my miss is still there at idle...
I made a slow mo video that may explain it tho! Check at :46 & 2:08; there’s an extra spark pulse!
https://youtu.be/IP02i0sUkIg
You have your vacuum advance hooked up to the wrong port, or your idle speed is too high/throttle is open too much at idle. You should have no vacuum on the distributor at idle. Some people do run manifold vacuum with vacuum all the time at the distributor, but over and over I have found most Fords run better with ported vacuum to the dist. That means no vacuum to the dist at idle.

Remember, you do not need the vacuum advance for the engine to run properly. It is only there to improve efficiency (fuel mileage). You really should disconnect it, tune the engine with it disconnected, go on test drives with it disconnected, and then connect it afterward. If it then causes problems, it needs to be adjusted, usually by getting an adjustable vacuum advance unit.
 
  #26  
Old 02-12-2019, 09:24 PM
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Originally Posted by Franklin2 View Post
You have your vacuum advance hooked up to the wrong port, or your idle speed is too high/throttle is open too much at idle. You should have no vacuum on the distributor at idle. Some people do run manifold vacuum with vacuum all the time at the distributor, but over and over I have found most Fords run better with ported vacuum to the dist. That means no vacuum to the dist at idle.

Remember, you do not need the vacuum advance for the engine to run properly. It is only there to improve efficiency (fuel mileage). You really should disconnect it, tune the engine with it disconnected, go on test drives with it disconnected, and then connect it afterward. If it then causes problems, it needs to be adjusted, usually by getting an adjustable vacuum advance unit.
Franklin, you may be a genius! I had disconnected the vacuum lines the other day when I was messing with the dizzy. Maybe I swapped them. -would be an easy over sight. Iíll check it tomorrow and let you know .
 
  #27  
Old 02-13-2019, 07:36 AM
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Originally Posted by Franklin2 View Post
You have your vacuum advance hooked up to the wrong port, or your idle speed is too high/throttle is open too much at idle. You should have no vacuum on the distributor at idle. Some people do run manifold vacuum with vacuum all the time at the distributor, but over and over I have found most Fords run better with ported vacuum to the dist. That means no vacuum to the dist at idle.

Remember, you do not need the vacuum advance for the engine to run properly. It is only there to improve efficiency (fuel mileage). You really should disconnect it, tune the engine with it disconnected, go on test drives with it disconnected, and then connect it afterward. If it then causes problems, it needs to be adjusted, usually by getting an adjustable vacuum advance unit.
Good catch, I was scrolling down to get here and saw the cap on the port that should go to the dist vacuum advance can. Then I saw your post about it.
Would be nice if that was the issue.
Dave ----
 
  #28  
Old 02-13-2019, 08:30 AM
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If a motor's healthy with no vacuum leak, and a cam that small, you'd want to see close to if not 20 psi vacuum at idle in park. Have you gone around everything with propane to ensure you don't have vacuum leak? Is your needle steady or moving any on your vacuum gauge when you're checking? If wiggling a little and move a tad, you have vacuum leak.
 
  #29  
Old 02-13-2019, 09:20 AM
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Originally Posted by Odisvan View Post
If a motor's healthy with no vacuum leak, and a cam that small, you'd want to see close to if not 20 psi vacuum at idle in park. Have you gone around everything with propane to ensure you don't have vacuum leak? Is your needle steady or moving any on your vacuum gauge when you're checking? If wiggling a little and move a tad, you have vacuum leak.
the needle definitely wobbles around. I can hear/feel an awful lot of air sucking in at the electric choke - I assume thatís normal? Iíll have to look around for any other leaks
 
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Old 02-13-2019, 09:32 AM
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no, needle should be solid. You have vacuum leak screwing with you. Find it FIRST, then work on tuning.
 

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