'79 Ford Ignition Help

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07-07-2015, 09:38
MED

'79 Ford Ignition Help

My father gave me his 1979 Lincoln Mark V Collector's Series; it is has 1571 original miles on it. Typical Ford of this era, I am having problems with the ignition. The engine is basically new and original to what it was when it rolled off the assembly line. There is a weak spark (visual spark intensity inspection) to all eight cylinders; it fires and runs but fouls all eight plugs in about 30 minutes or so of running. The goofy ignition module was replaced once about 15 years ago. I tried a different coil. The plug wires, cap and rotor are all new but I inspected them. I am kind of at a loss with this one. Any Ford guys have any ideas?

Edit: It looks like there is an ignition voltage regulator. I guess I will try to find this guy.
07-07-2015, 13:35
DOC

I would like to offer some advice of checking for a fried wire connection. However, when my Mustang was doing this very same thing I just put an MSD multispark box on it and it sent enough fire to each plug that I haven't had a problem since.
07-07-2015, 13:47
TFOGGER

The Ford ignition modules are crap(on the fender or firewall). You may also have a bad ballast resistor(between the ignition switch and the positive side of the ignition coil). The ballast resistor is a white ceramic resistor usually bolted to the firewall. Back in the day, I rewired my Granada to use a GM HEI module after replacing 3 Ford modules in about a year and a half.
07-07-2015, 13:59
Great-Kazoo

What does the tail pipe look like, clean, oily / sooty, black?
07-07-2015, 14:29
TFOGGER

Quote:

Originally Posted by Great-Kazoo

What does the tail pipe look like, clean, oily / sooty, black?

That question could be really funny, taken out of context...[ROFL1]
07-08-2015, 07:52
MED

Quote:

Originally Posted by Great-Kazoo

What does the tail pipe look like, clean, oily / sooty, black?

Carbon is coming out the exhaust, and the plugs are fouled with carbon and smell like fuel. If the spark wasn't so weak, I would be looking at the carb.
07-08-2015, 07:54
MED

Quote:

Originally Posted by TFOGGER

The Ford ignition modules are crap(on the fender or firewall). You may also have a bad ballast resistor(between the ignition switch and the positive side of the ignition coil). The ballast resistor is a white ceramic resistor usually bolted to the firewall. Back in the day, I rewired my Granada to use a GM HEI module after replacing 3 Ford modules in about a year and a half.

I know all about the POS Ford ignition box; I replaced it once on this car when it had around 1,000 miles on the odometer. I thought about replacing it again, but a failed module usually results in a no spark condition,
07-08-2015, 07:56
MED

Quote:

Originally Posted by DOC

I would like to offer some advice of checking for a fried wire connection. However, when my Mustang was doing this very same thing I just put an MSD multispark box on it and it sent enough fire to each plug that I haven't had a problem since.

If it wasn't a 1571 mile collector car, I would rip out the whole ignition system and use an MSD; actually, I would probably rip out the engine.
07-08-2015, 13:46
DOC

It can be installed and returned to factory without changing anything. Although it might be just rich. The floats might need adjusted. A lot of problems can be caused right there. Air fuel screws out of adjustment. Valve guides can be cracked too. Without more information it's hard to tell why it's fouling plugs.
07-08-2015, 14:28
Great-Kazoo

Quote:

Originally Posted by MED

Carbon is coming out the exhaust, and the plugs are fouled with carbon and smell like fuel. If the spark wasn't so weak, I would be looking at the carb.

Before the carb i'd go to the cat converter. Even with weak spark there are telltale signs your converter is or has taken a shit. Yes even with the lack of mileage it has. Who knows how many times someone had ran the vehicle for a few minutes, to "charge the battery". Unfortunately doing a short run (multiple times) does more damage to the engine than letting it sit there.
07-08-2015, 14:40
MED

Quote:

Originally Posted by DOC

It can be installed and returned to factory without changing anything. Although it might be just rich. The floats might need adjusted. A lot of problems can be caused right there. Air fuel screws out of adjustment. Valve guides can be cracked too. Without more information it's hard to tell why it's fouling plugs.

I can't see the carb changing sitting in my father's garage. Well, you never know with that FORD two barrel on there; I did flush out the gas. He started and ran it about once a month for the life of the car and one day it just ran like shit. However, with the spark being put off on all eight new plugs, it would barely run my lawn mower. It fires like the coil is going bad but its not, and the system is fully charged. alternator charging, etc. If it wasn't firing at all, it would be a lot easier to track down the problem. I was hoping somebody had the oh yeah, I had this...no such luck.
07-08-2015, 14:43
MED

Quote:

Originally Posted by Great-Kazoo

Before the carb i'd go to the cat converter. Even with weak spark there are telltale signs your converter is or has taken a shit. Yes even with the lack of mileage it has. Who knows how many times someone had ran the vehicle for a few minutes, to "charge the battery". Unfortunately doing a short run (multiple times) does more damage to the engine than letting it sit there.

Yeah, those old pellet converters really sucked; I will look at it. My dad really didn't know what he was doing. He would start the car and rev the hell out of it for 20 minutes and turn it off. I tried to stop him but had little success in that. I keep a trickle charge on my stored vehicles, drain and fill the oil and fire them in the summer. Usually, a clogged converter will cause significant back pressure and heat issues which I don't see. The exhaust seems to be flowing, but I really don't know what is "good" for this car since it always had that '70s sputter.

Edit: My dad is 90 now, I would like to get the car running again to take him out at least once while he is still around.
07-09-2015, 10:18
DOC

Get a multi meter on the coil wires to see if they are 12 - 14 volts. If you can test the voltage coming off the coil that might help but I don't know how to do that. If the wires are shot it would provide a weak spark too. That is as narrowed down as I can think to start with.
07-10-2015, 22:57
ben4372

I'd get an Ignitor II, or similat. Fits under the original distributor cap, reversible. Around 15 years ago, I had a module go out in my Bronco. Took three tries at NAPA to find one that lasted. Was giving me weak spark. These are simple systems. A Haynes manual should put you on it quick.
07-10-2015, 23:50
Ah Pook

I'm not an expert on Ford. That said, Pertronix Ignitor and coil goes a long way in fixing spark/idle/performance problems. Using the appropriate Pertronix coil does away with the ballast resistor.

Fowling plugs sounds like it is running rich. Where did the car come from? Most stock carbs are tuned/jetted for sea level. Jet size changes about ever 2000 feet.
07-11-2015, 06:50
BPTactical

The thing that is critical on the Ford "brain boxes", the "connector" where the wires meet the box is a particular color. You need to make sure the replacement box has the same color connector. If it is not it will give you issues like you describe.
Typically if the brain box fails you get no spark whatsoever.
If the vehicle has been sitting that long, rebuild the carb. The gaskets have dried up and no longer capable of sealing.
Is it an Autolite or Motorcraft carb? If a Motorcraft it is a Holley carb. If it ever backfired even once through the carb the power valve is toast, creating a very rich idle condition.
Do check the ballast resistor for the ignition, I don't recall if it is a physical resistor or a resistor wire.

The car does not have enough miles that the issues are going to be a worn out this or that. Look for indicators of critters chewing wires etc.
Good luck, 79 Lincolns are awesome old long noses.
07-14-2015, 12:18
MED

Quote:

Originally Posted by ben4372

I'd get an Ignitor II, or similat. Fits under the original distributor cap, reversible. Around 15 years ago, I had a module go out in my Bronco. Took three tries at NAPA to find one that lasted. Was giving me weak spark. These are simple systems. A Haynes manual should put you on it quick.

I need to get another module for it; the one in it is correct and worked for a long time but I didn't know if these would result in a weak spark condition so this is helpful. I thought these going bad only resulted in a no spark condition, which is what happened the first time.

Quote:

Originally Posted by Ah Pook

I'm not an expert on Ford. That said, Pertronix Ignitor and coil goes a long way in fixing spark/idle/performance problems. Using the appropriate Pertronix coil does away with the ballast resistor.

Fowling plugs sounds like it is running rich. Where did the car come from? Most stock carbs are tuned/jetted for sea level. Jet size changes about ever 2000 feet.

It wasn't running rich for the first thirty-three years; car came from my dad's garage in Monument. If you saw the spark intensity of the plugs, you could see the problem. The spark is barely strong enough to run, but not burn the fuel/air completely. I thought for sure it was the coil when I first looked at it. If I can fix it w/out changing parts, I would like to exhaust that first. However, upgrading the ignition system is sure tempting! I tried to replace the resister you referenced, but I couldn't find one. I could try that again.

Quote:

Originally Posted by BPTactical

The thing that is critical on the Ford "brain boxes", the "connector" where the wires meet the box is a particular color. You need to make sure the replacement box has the same color connector. If it is not it will give you issues like you describe.
Typically if the brain box fails you get no spark whatsoever.
If the vehicle has been sitting that long, rebuild the carb. The gaskets have dried up and no longer capable of sealing.
Is it an Autolite or Motorcraft carb? If a Motorcraft it is a Holley carb. If it ever backfired even once through the carb the power valve is toast, creating a very rich idle condition.
Do check the ballast resistor for the ignition, I don't recall if it is a physical resistor or a resistor wire.

The car does not have enough miles that the issues are going to be a worn out this or that. Look for indicators of critters chewing wires etc.
Good luck, 79 Lincolns are awesome old long noses.

I matched the module to the car back around 2002. It worked correctly for 10 years without a problem until now. It is definitely burning rich, but the ignition system is also not working correctly. However, none of the conditions changed regarding carb adjustment and location. I am not familiar with the carb issues you described so I may need to look into that. I am far more familiar with the HEIs and Quadrajets, and I pretty much loathed the Duraspark stuff. There is definitely a resister, I brought it into the parts store and couldn't locate the part. I liked the Mark Vs too; however, they were a lot better in '77 & '78 when they had the 460s. This small block two barrel is a POS!

I am taking a break on it for now since I have other priorities, I will get back to it again and report.

Thanks for all the replies!