Ignition of choice

[joser]

I am running a 351W and have been having some starting problems and am pretty sure they are due to the ignition. I have electronic ignition on my 351W with the Ford Duraspark ignition control box.

My enging will crank for a long time. Once in a while it will not start at all. Then, after no change, it will start up, usually as I am letting go of the key.

What are your guys running? How can I test the components or pinpoint which is causing the problem?

Thanks for the help, man am I confused/frustrated.

 

[70_Steve]

I'm running a Duraspark in my 351. Starts pretty much at the touch of the key. Your comment about it starting sometimes as you're letting go of the key makes me think its either a wiring problem or a problem with your ignition switch.

 

[tj]

There are a few things that can cause this with a Duraspark system. My philosophy is to start eith the easiest to get at & cheapest to fix then make my way towards the more expensive and harder to get at.

So here goes:

Probably the first thing to check is your Dura spark connections for a good uncorroded connection. Careful with the black plugs as it is easy to break the locking arms. There is supposed to be a dielectric goo between the connectors. Over time this tends to dry out, crack and let water through to corrode the connector pins. If it has been a long time since your dielectric goo has been replaced it would not hurt to wipe off the old stuff and liberally smear on some new goo. There is a wire that goes from the coil connector (bat side) to the ignition. It bypasses the ballast while the starter motor is turning. Make sure this wire is connected & in good shape. If it is not you will get the symptoms you described. When in doubt temporarly run a wire from the battery to the batt side of the coil & try to start the engine. If the problem goes away you know it has to do with the ballast bypass circuit.

May I assume your plugs haven't died of old age, the gap is correct and carbon core wires are no more than a couple years old?

Pop your distributor cap and look for dirt build up or carbon lines. The Duraspark is a high voltage system and there could be surface arching on the cap surface between the posts.

Next step is swaping out components. I've leaned to keep a spare electronic module & a spare coil in the on-board trip spares box.

I lost a coil once on a mountain ridge high above Moab. Symption was similar to a clogged fuel filter. Barely ran and had no power. I limped into Moab and found the problem to be a leaky coil that was generating low voltage. The coil was aftermarket & about a year old.

The second failure is one that may be your problem. Late Sunday afternoon cold, windy, snow blowing near horizontally, over 500 miles from home. Engine would not start or even pretend to catch. I had a spare module in the spares box. Swapped it out and the engine fired right up. What makes this failure interesting is that the engine was hard to start for about 2 months before the module went out. It had the exact same symptions you described.

So if the problem is not in your primary wiring system try swapping out the electroic control module. You should keep one in your spares kit anyway.

Lastly don't forget most fuel and ignition problems have symptoms that mimic each other. I can not count the times in past years where I replaced fuel filters, fuel pumps, rebuilt carbs and belw out fuel lines because of slipped points or a bad condensor.

Good luck

TJ

 

[SeaBiscuit68]

Your comment about starting as you release the key struck a note with me. I once had an old ford with a bad ignition switch and it did just that. You could test this idea by bypassing the switch at the relay/solenoid and see if she fires. Worth a shot.

 

[74bronc]

have you replaced the control module? they are only 15 bucks and I would start there.

Also, check carefully the resistance wire that goes from the back of the ignition switch to the coil. I had a '73 EB that had a break in that wire and it would do exactly what you are describing. Actually, someone had cut that wire, done a half ass splice and the splice had heated up and created an intermittent connection.

 

[70_Steve]

I have electronic ignition on my 351W with the Ford Duraspark ignition control box.

Who installed the Duraspark?? Just wondering if you knew for sure where the Run and Start connections were made.

 

[joser]

70 Steve

I had Desert Fox install it a couple years ago. I am not sure where Run and Start are located. I am assuming you mean where they attach to the vehicle wiring?

This thing needs a re-wire in the worst way. I think that will be the big Summer project.

Thanks for the help.

 

[HotWheels]

I've got the MSD off-road ignition and pro-billet distributor in my 77. All the old stuff is gone. Runs great.

 

[70_Steve]

I am not sure where Run and Start are located. I am assuming you mean where they attach to the vehicle wiring?

Yes, that's what I was asking. I've attached a simple diagram of the Duraspark wiring. Not exactly correct, but close enough. If you have a voltmeter (and a friend ) one thing you want to check is whether you have voltage to the coil with the key in the START position. On most Broncos, and our 70, with the key in the RUN position, power to the coil comes from the ignition switch. BUT!!! (and it's a big butt) with the key in the START position, the power comes from the I terminal connection on the starter solenoid. If the starter solenoid is bad, or that connection is loose or missing, that would explain why sometimes the engine will start as you turn the key back to RUN.

Where in Phoenix are you?

 

[joser]

70 Steve

Thanks for the help. I will enlist some help this evening, to help me verify voltage to the coil in various key positions. The wife is under the weather, so I may be forced to ask my neighbor, the Jeep owner who loves to see the Bronco suffering, for help.

I am going to go to Checker and buy another Ignition module and try that also.

I will post results of this evening's events.

 

[joser]

70 Steve

I live in Peoria (99th Ave & Pinnacle Peak area) where are you? Do you belong to the AZ bronco club?

I swapped the ignition module last night and it seemed to fix the problem. I think I need to test the system to weed out other problems. I have zero experience, and less confidence, troubleshooting electrical problems and lack the right tools. So as I learn what I need to do, I also am learning the right tools to acquire.

Thanks again for the advice.

 

[Rustytruck]

The mag pick-up in the distributer fails far more often than the ignition module. Usually fails after warm up. I have seen it go, sometimes worky, sometimes not worky.

 

[antnykk]

Put a test light on your ignition and make sure it is powered while cranking. Starting while letting off the key could be from the ignition being power with a accesory instead of an ignition source.

Acc= hot with key on, but no juice while cranking

Ign= hot with key on and also while cranking

 

[70_Steve]

70 Steve

I live in Peoria (99th Ave & Pinnacle Peak area) where are you? Do you belong to the AZ bronco club?

I live pretty close to you. 95th and Beardsley! Been an ACB member for 5-6 years.

If you need some help doing stuff, send me an email stevelancea@cox.net .