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

300-6 Idle miss

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  #31  
Old 01-31-2019, 06:21 PM
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Originally Posted by 1981 F100
I went ahead and bought a brand new module, as the one a friend gave me had the black epoxy on the underside showing signs of running down the sides
The one in my project truck is showing the same thing running down the inner fender well but is still working.
Then again I am only moving it in / out of the garage and I have a spare I will carry when the truck gets on the road.
Dave ----
 
  #32  
Old 01-31-2019, 08:31 PM
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Originally Posted by FuzzFace2
The one in my project truck is showing the same thing running down the inner fender well but is still working.
Then again I am only moving it in / out of the garage and I have a spare I will carry when the truck gets on the road.
Dave ----
I didn't want to chance it, so I sprung for the new one, and keep the old one for emergency backup. Luckily I don't have to drill any holes to mount the module, the holes are already there. Would adding a ground wire from one of the mounting bolts, to the fender be a good idea?
 
  #33  
Old 02-01-2019, 07:19 AM
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This allows air to flow under the module:



Or, you can mount one [or two/tandem] near the front [radiator support] for additional cooling and an "in place" back-up:



Or, mount the 2nd [back-up] ignition module on top of one on the fender liner.

 
  #34  
Old 02-01-2019, 03:31 PM
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Got the Duraspark dizzy, coil and wiring all connected up, attaching photo of how I have the module mounted, I used some nylon spacers, between the fender and module. I guess all that's left now is to double check things, and then fire it up. Would a ground from one of the module mounting bolts to the fender be a good idea? Also what about the sending unit for the temp idiot light? is it part of the Duraspark harness, and where is it located on the engine?
 
  #35  
Old 02-01-2019, 05:18 PM
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Originally Posted by 1981 F100
Got the Duraspark dizzy, coil and wiring all connected up, attaching photo of how I have the module mounted, I used some nylon spacers, between the fender and module. I guess all that's left now is to double check things, and then fire it up. Would a ground from one of the module mounting bolts to the fender be a good idea? Also what about the sending unit for the temp idiot light? is it part of the Duraspark harness, and where is it located on the engine?
So just verifying, all of it just plugged into your existing plugs?

You should have a oil pressure wire and a temperature wire. I looked at the diagram below, they say it's connector c325 and c325a. I went back in this post and looked at the EEC 4.9 ignition diagram, the coil hot wire is on the same c325 and c325a connector, so yes, the oil pressure and water temp wires are in one of those plugs common with the ignition coil.



 
  #36  
Old 02-01-2019, 05:40 PM
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Yes, what is in my photo are the plugs from my truck harness and the Duraspark harness, really was a plug and play setup
 
  #37  
Old 02-01-2019, 06:04 PM
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How's she run?
 
  #38  
Old 02-01-2019, 06:07 PM
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Originally Posted by jackietreehorn
How's she run?
Haven't tried it yet, gotta clean the plugs, they got really carbon fouled from how it had been running, then I need to do a couple other things too. Should be firing it up tomorrow, it ought to run a helluva lot better. Now that the EEC-IV harness is disconnected, should I wait till I fire it up, before hacking that old harness out?
 
  #39  
Old 02-01-2019, 06:11 PM
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Originally Posted by 1981 F100
Haven't tried it yet, gotta clean the plugs, they got really carbon fouled from how it had been running, then I need to do a couple other things too. Should be firing it up tomorrow, it ought to run a helluva lot better. Now that the EEC-IV harness is disconnected, should I wait till I fire it up, before hacking that old harness out?
Probably not a bad idea so you will know instantly if you inadvertently cut the wrong wire...
 
  #40  
Old 02-01-2019, 06:46 PM
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Originally Posted by jackietreehorn
Probably not a bad idea so you will know instantly if you inadvertently cut the wrong wire...
Yes, I do have all the EEC ignition wiring all disconnected and out of the way. I might run an extra ground from a module mounting bolt to the fender , haven't decided yet. What's a good ignition timing to set it at with the Duraspark?
 
  #41  
Old 02-01-2019, 08:05 PM
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Grounding the module case is a good idea. It might be isolated from the circuit but it won’t hurt. I grounded it to the block and snuck the wire in the loom going to the dizzy.

10 deg is a good starting point but you can really adjust it until you get a timing light to use while it’s running. Then just crank up the timing until it pings and move back a smidge or two.

A cool way to get maximum timing is to use a vacuum gauge measuring to max vacuum and then backing off. This method is for when you’ve already got the carb dialed in and it’s running good.
 
  #42  
Old 02-01-2019, 08:27 PM
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Originally Posted by jackietreehorn
Grounding the module case is a good idea. It might be isolated from the circuit but it won’t hurt. I grounded it to the block and snuck the wire in the loom going to the dizzy.

10 deg is a good starting point but you can really adjust it until you get a timing light to use while it’s running. Then just crank up the timing until it pings and move back a smidge or two.

A cool way to get maximum timing is to use a vacuum gauge measuring to max vacuum and then backing off. This method is for when you’ve already got the carb dialed in and it’s running good.
I just happen to have a timing light, so I can easily set it for 10 deg. Should see one heck of an improvement on how it runs.
 
  #43  
Old 02-03-2019, 10:12 AM
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Well, some good news, I got it to run pretty good, does not blow black smoke like it was doing. Came to find out by looking at a firing order diagram, previous owner had the EEC dizzy one terminal off. So like a boob I put the Duraspark one in same way. Had to take it back out today and reset it. Runs a lot better, just a slight idle miss, probably due to the gas/carbon fouled plugs.. What is a good copper core plug to run in these 300's? I might put a fresh set in and start over. I have Motorcraft BSF42 in it now, about 80 percent of my driving is in town, or no more than 10 miles away with occasional trips longer than that. Currently have them gapped at .044
 
  #44  
Old 02-03-2019, 10:58 AM
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I recommend those same plugs and that same gap. That is what I use and have had good luck so far..

Don't forge to adjust your idle mixture afterwards.
 
  #45  
Old 02-03-2019, 11:32 AM
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Originally Posted by Wagonboy
I recommend those same plugs and that same gap. That is what I use and have had good luck so far..

Don't forge to adjust your idle mixture afterwards.
I guess I could just clean them, or let the carbon burn off. I do have some slight tweaks to make yet,and get the temp sender wire hooked up along with tearing the EEC harness out. but is running way better. Now, is the coil supposed to be mounted sideways, or pointed straight up?
 


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