I'm sorry pawpaw, but I can't even find the thread index page. I am familiar with the "wasted spark" system as I have an old hay baler with a twin cylinder Wisconsin engine that uses that process. It only has one coil in the mag and one set of points. Both pistons travel in unison and they both fire at the same time, one on exhaust and the other on intake. It will run perfectly when the plug wires are reversed or if I put the mag in 180 degrees off. It looks to me like # 1 and #5 use the same coil in the pack on my Ranger, thus one fires on the exhaust stroke while the other fires on intake. I'm not sure what I am going to try next with my old truck, maybe check the compression on all of the cylinders. My code reader is capable of running tests with the engine running but I'm not familiar with how to do that. My mechanic friend knows more about it than I do. I plan on calling him again this week end.

 

OK, scroll up to the top of this page & in the header, click on the blue Ranger & B-Series. That'll take you to & open this forums thread index page & atop it next to a red "Read First" you'll find the "Tech Info" link, so click on it to open that thread & scroll down to find the "why use double platinum plugs" & next to the last link down in the Miscellaneous section, you'll find a link to the 3.0L Tech Info thread put together by Rockledge, so click on it to open that page.
If you still have trouble getting to the thread index page, click here. https://www.ford-trucks.com/forums/1...formation.html Let us know if you find the links your interested in.

Yes, on our waste spark ignition system cyls 1&5, 2&6, 3&4 are paired together at the coilpack.
Lots of 3.0L good to know info there.

 

Got it pawpaw, thanks. I know just enough about computers to be dangerous. My son bails me out quite often. He takes control of my computer from his home in Boston with me living in Northern Maine. I'll read the post first chance I get.

 

Roger on the computer, me too, when I get stuck, I call the Daughter, or Granddaughters to bail me out & get me back on track!!!! lol

 

Here is a link on how to perform some diagnostic tests on your coil pack.
Part 1 -How to Test the Coil Pack (Ford 3.0L, 3.8L, 4.0L, 4.2L)

 

Thanks for the link on testing procedures. I hope to get to this on the week end. One other thing that I discovered yesterday is that the truck starts and runs perfect when the engine is cold. It only starts missing after it has ran for a few minutes and the temp has come up.

 

OK, that's a good clue, the miss is temp sensitive. Have you listened at the engine top end when its missing, to determine if it gets noisy, like a lifter tap????
Have you discovered a way to get a home made rubber tube stethoscope in there to have a listen to #5 fuel injector. If not, have you hooked up a vacuum gauge, to see what it suggests????
Keep us posted on your trouble shoot.

 

I have not done any of that yet but I sure intend to. The engine has no unusual sounds at all (other than a cracked exhaust manifold on the #5 side that has been there for 3 years) It's quite noisy until it warms up and then it quiets down to the point that it passes the state safety inspection. I can't even see the #5 injector because it's hidden under the intake plenum. I can just barley see # 1. I can see all 3 on the other side. I do have a stethoscope that would be long enough if I could see what I was doing. I'm sure that my mechanic friend will have some suggestions too and I plan on printing all of these suggestions out for him as well.

 

I had to drive the truck nearly 50 miles to get it to start missing again. When it was not missing, it ran better than it has for a long time (new plugs and wires). Things are now pointing towards a bad head gasket. We checked for vacuum leaks and swapped the plug wires around to try to make the problem go to another cylinder. All were negative. It still has a yellow spark on #5 while the rest are blue. My friend then found a white scale type substance running down the side of the block under the head and near #5. There is also a little bit of smoke coming from that area as well. Another thing that I have noticed from time to time, not often but on occassion, is that the coolant gurgles in the overflow tank for a few minutes after I shut the truck off. It stops if I "burp" the radiator cap. I still cant figure out how it can have 150 pounds of compression with a bad head gasket. The repair bill is going to be more or less what the truck is worth. I know that it is not right, but I'm half way tempted to try dumping some of that miracle head gasket restore stuff in it and get a radiator cap that has less pressure.

 

Also, the coolant is not always full to the top like it is supposed to be. It's down a few inches but still visible in the radiator. I don't see any indication of coolant going in the oil but it has to be going somewhere. I'm guessing now that it is running down the side of the engine and burning off.

 

Put a pressure gauge in place of the radiator cap, to see if its holding pressure. Most autoparts stores have the test kit in their Loan-A-Tool program.

The yellow/weak spark on #5 cyl could be from a low B+12 volt input to the coilpack, or a faulty/high resistance computer ground switching driver for #5 cyl. So back probe the #5 coilpack primary connection to measure the under load voltage going to #5 primary winding.

 

sounds more and more like a blown head gasket.
A block checker can be borrowed at O'reily's, its a test the checks for combustion gases in the cooling system.
http://www.blockchek.com/index.htm

 

I think that my father has one of those pressure tools. Is that the pump that you use to pressurize the system to find leaks without running the engine? I am assuming that the #5 primary wire that you are referring to is one of the four small wires that plugs into the coil pack? Just probe into that wire while the truck is running (and missing) and use a multi-meter to be sure that there are 12 volts?

 

The reason for 150 psi compression might be because the engine was not fully warmed up. When the engine warms up it expands, that creates the opening for combustion gas to pass into the cooling system and cause the gurgling at shut down.

 

One more thing that may explain the yellow spark. When putting in the new plug wires, I found a ground strap connected to the fire wall. It was broken with the other end just hanging there. Last summer I had a clutch put in and also replaced the oil pan. They had to raise the engine up a few inches so that the pan would clear. I am assuming that is how the strap got broken. Perhaps that broken wire caused some problems. I hadn't noticed it and it ran that way for over a year. Anyway, I ran a new 12 gauge wire from the firewall to the engine block.