Ford Duraspark II question

The Ford Duraspark systems more or less shut down when system voltage goes below 10.5 volts, if your battery is weak, even though it appears to be working the starter okay, this may in fact be your problem.

Easy enough to check, connect a volt meter across the battery, crank the engine and watch for how low the voltage goes.

Had an AMC Eagle in last year that had been to every shop in the area, intermittant no start/no spark, new module, new coil, new cap-rotor-wires, new pine scent air freshener.... The fix was a new battery even though it appeared to be able to spin the starter well enough.

Indian Summer

Install a capacitor and a doide near the Duraspark system.

The capacitor holds 12vdc while the diode keeps currents directional, thus keeping the cap at 12vdc for a second or two. Find a suitable component. Another gentlemen had just about the same problem on his Honda/Rover.

He says, "So I switched on many higher load things like the heater and the rear screen and the headlights etc and then keyed it, but it wouldn't start on the key nor when I released the key back to 'Run'. I turned off all the 'extras' and tried it again and it started as I released the key! So, it looks as if my igniter module is playing up and won't do its job unless there is over twelve volts at its supply terminal."

I had a similiar problem with a 79 Linc. Mark V. I got a new ignition module and it worked for 2 months. I started to have the same problem again. I kept replacing the ignition module (on warranty) until I was afraid that my parts store wouldn't honor the warranty. I checked the ground circuit voltage on the ignition module and found it to be ok. Found out that the pick-up coil was at fault. I got a new one and haven't had a problem yet since about August. I used a Haynes repair manual for the assistance that led me to the pick-up coil problem. I also installed a ground wire from the pick-up coil inside the distributor to a bolt on the engine to make sure that it was getting grounded. Hope this helps you.

I personally would have installed a Pertronix unit under the stock distributor to keep it looking factory, but that is now besides the point. After you get this fixed you will want to install a starter solenoid switch from a later model Ford that is diode suppressed. They put a zenor diode in these to stop the big voltage spikes from zapping the electronics in the modules and pickup assemblies. Any good parts man will be able to give you one of these without having to look in his book.

The price was right on the parts (long story, but Dad ended up with the old station wagon missing some parts and called the salvage yard to come get and I pulled the distribtor and ignition). The large diameter blue adaptor and cap didn't fit, so I am running the stock cap hoping I don't get cross fire. Has worked fine for several months and looks stock.

Something else I need to research is timing curves. The "new" distributor came from a '76 460cid so I'd expect the vacuum advance and centrifugal advance are different. The stock motor is the 351c with 2v heads. I have added a performer intake and cam with a Holley carb, so the curve needs changing anyway... Any suggestions as to what would be the correct timing advance numbers would be appreciated or a link.

Thanks to all who have replied. I will do a quick experiment by first swapping batteries and if that doesn't work, isolate the ignition system on a known good battery or on jumper cables to ensure it is getting the 12 volts and see what happens. The starter definitely spins faster with a jump, so that may be the problem, especially based on the replies.

You sure could be describing a dirty connection on the starter relay.

The relay has 2 small side posts. One is the trigger signal from the key switch to energize the relay, the other provides 12 volts to the coil when the starter is cranking.

When dirty, the coil doesn't get power until you let off the key from start to run, then the ballast wire kicks in.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

bobby wrote:

Would a very rich to flooding condition cause the symptom (engine won't hardly fire during cranking, but fires once key is released and goes to the run position)?

This weekend, I:

• Changed battery - no improvement

• changed ingnition module - no improvement

• Reinstalled old module and removed air cleaner to find it dirty and wet from gasoline. Tried to start with air cleaner removed and it started up, but again only fired after releasing the key from the start position. The first couple of tries, when it fired, it threw gas out of the vent of the primary side of the carb (Holley 4bbl). Once it started, it would restart as it should, while cranking. Tried to adjust the float levels. Primary was ok, but the oring on the float adjust of the secondary was crumbling. Replaced this and it starts up fairly nice right now (with the air cleaner removed), but often does something weird (to me anyway). When I turn the key to on, radio comes on, etc. , turn a bit farther, radio turns off but turn a little farther, apparently a cylinder fires because the engine will bump reverse rotation 1/2 turn or so, turn key a little farther and starter motor engages and it starts. If I turn key normally, this kick back hits the starter pretty hard and makes unpleasant noises... Why would that cylinder fire in such a case? I would expect it to fire when the key is first turned on if anything. Is this a symptome of timing set too advanced?

Thanks again to all who reply. As for my original problem, I don't know if the wet/dirty air cleaner was the problem or if unplugging and reconnecting the ignition module fixed a bad connection.

Bobby

You are describing a dirty connection on the starter solenoid or relay.

When the starter is turning, a wire comes from the solenoid/relay to give the coil 12 volts.

When you let the key go to run, the power switches over to a ballast or power wire to the coil.

These are two separate circuits that provide coil power.

I would test it this way. I would get it running so I am sure it isn't flooded all to heck, then shut it down. I would then run a jumper from the battery positive to the coil positive and see if it starts up correctly and fires when the starter is turning.

If it does, I would then clean or replace the solenoid.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Mike,

Thanks for the inputs. I tried the jumper wire a couple of weeks ago adn it didn't seem to help (see 2nd paragraph of original post if it is still there). Right now, I believe I may have 2 problems. One with flooding and the other with ignition. The ignition problem may have been a dirty connection at the controller as it started up fine several times yesterday with the exception of the kick back just prior to starter engaging.

Bobby

Mike Roma>

That's why I mentioned getting it running before trying the power jumper. You didn't seem sure if it was flooded all to crap or not at that point.

Our Jeeps have the Ford ignition in them and can use the duraspark setup and when I see your symptoms, I always think that damn starter relay has gotten dirty again. At least they are less than $10.00 to replace.

Mike

bobby wrote:

That happened to mine out in the bush on a week long run once. The second post lost it so I just wired the coil tag to the key switch solenoid trigger wire.

It would kinda start, but I didn't like the back fire out the carb if it missed so fixed it's case.

My Jeep is still wired that way. I have a butane powered soldering iron so my trail fix was a good solid one.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's