Engine will not fire, coil questions.

[In The Ten Ring]

My truck has the original 250 six cylinder engine.

OK. Dad and I tried to start the truck just now.

What we know (dad used his tester).

1). Wire from coil to distributor is good.
2). Distributor points are not stuck.

What we need to find out.

1). Will a bad condenser prevent a coil from firing?
2). Can a coil "go bad" just sitting for 12 years and not being run?
3). Could we have a wire grounded somewhere?
3a). Where all might a wire be grounded?

*We don't see how it could be a grounded wire, truck drove to where it is now, it hasn't been moved from my garage, there is no evidence of any mice or other animals, and I haven't touched those wires.

Still, a grounded wire is our biggest fear.

Advice? Suggestions? Answers?

[demian5]

Originally Posted by In The Ten Ring

Can a coil "go bad" just sitting for 12 years and not being run?

Was this the first try at starting it after sitting for 12 years?

Does it have spark at the cap and spark plugs?
Is it the 12 YO gas?
Is the carb getting gas to it?
Did you try and put a little gas down the carb and see if it tries to start?
Did you drain the tank and carb prior to it sitting for 12 years?

I have a Chevelle that sat for 10 years, it was the fuel system that was the problem, not the ignition.

[In The Ten Ring]

Originally Posted by demian5

Was this the first try at starting it after sitting for 12 years?

Does it have spark at the cap and spark plugs?
Is it the 12 YO gas?
Is the carb getting gas to it?
Did you try and put a little gas down the carb and see if it tries to start?
Did you drain the tank and carb prior to it sitting for 12 years?

I have a Chevelle that sat for 10 years, it was the fuel system that was the problem, not the ignition.

1). This is the second attempt at starting.
2). Coil would not fire, we tested and found that. So it cannot spark at the cap and thus, it cannot spark at the plugs.
3). Carb is getting fuel.
4). We sprayed new gasoline (non-ethanol) into the carb.
5). Fuel line is into a gasoline can of one month old non-ethanol gasoline.
6). Carb was removed and cleaned and completely rebuilt using a new NAPA kit by a mechanic.

[Coley]

Do you have a spare coil around?....even temporarily off another truck or a running small block chevy....usually no shortage of those around, lol.
Are you getting 12 volts to the coil?....check to see how much voltage is arriving with a multi-meter (easy quick test)
If it is below 6-8 volts....temporarily rig a hot wire from the battery to the coil to get a full 12 volts to at least ensure a good spark/voltage at the coil.

Coley

[In The Ten Ring]

Originally Posted by Coley

Do you have a spare coil around?....even temporarily off another truck or a running small block chevy....usually no shortage of those around, lol.
Are you getting 12 volts to the coil?....check to see how much voltage is arriving with a multi-meter (easy quick test)
If it is below 6-8 volts....temporarily rig a hot wire from the battery to the coil to get a full 12 volts to at least ensure a good spark/voltage at the coil.

Coley

Coley,

That's great. I just read your reply to dad and he smiled and said "didn't I just say that?" (I wasn't paying attention when he said that).

We hope to check it out tomorrow. He thinks he has another coil laying around too.

[B. W.]

If you have no spark at a spark plug, test for voltage at the coil. With the key on, one side should have voltage (8ish volts, the system uses a resistor wire to step it down from battery voltage) The negative terminal on the coil is grounded when the points are closed. With a test light on the coil, crank the engine, the test light should blink. If it does, the points are working ( they still might be out of adjustment but they are opening & closing)

If the test light does NOT blink, check for power at the points, check for proper point gap, clean the contacts (the contacts can become "glazed" & even though they close they do not make contact)

If the light blinks, put a spark plug in the other end of the coil wire. It should spark while cranking. (be sure & ground the spark plug) If it does not, your coil is bad. If it does, your distributor & coil are working, you should have spark at your plugs. If not, check (replace) the cap, rotor & wires, plugs as needed.

Side note:
If you leave the key on for an extended period and the points happen to be closed (the engine can stop with the points open) it will saturate the coil & can damage both the points & the coil. in worst case it can even cause the coil to blow up.

[Richard2112]

There was a time when we used to pull the coil wire and look into the the coil. If there was oil in there (where the distributor wire goes) it was definitely fried coil.

[LockDoc]

-
If the points are not new, the first thing I would try is one of the things B. W. suggested. Clean the contacts on the points. If you don't have a points file I have used a small folded piece of 220 grit wet-or-dry sand paper. Don't use wood finishing paper because the grit will fall off of the paper and lodge between the points contacts preventing them from making contact.

LockDoc

[In The Ten Ring]

We have already tested the coil, there is no electricity coming from it. We cleaned the contact points already in the distributor, we did that before testing the coil with a tester.

The points may have issues but the coil definitely has an issue. Going to try one of dad's spare coils tomorrow and I may have to buy a new one if his spares are not good.

I will keep this thread up to date and one thing is for sure.....I have a lot yet to learn about points and the rest of the electrical system!

[rockyrivermark]

Originally Posted by In The Ten Ring

We have already tested the coil, there is no electricity coming from it. We cleaned the contact points already in the distributor, we did that before testing the coil with a tester.

The points may have issues but the coil definitely has an issue. Going to try one of dad's spare coils tomorrow and I may have to buy a new one if his spares are not good.

I will keep this thread up to date and one thing is for sure.....I have a lot yet to learn about points and the rest of the electrical system!

Posted via Mobile Device

[rockyrivermark]

I would ditch the coil and dizzy and install a new HEI. it's easy and not expensive.
Points are a pain and finicky.

[Coley]

....or keep your original distributor and buy and install a pertronix 'undercap' electronic ignition.
Thats a great investment...I have that in both my older trucks......and will never go back to points, lol.
The HEI is popular too but I don't want issues with clearance to the firewall or problems with my factory tach, etc.

Coley

[In The Ten Ring]

I have noticed that HEI looks rather big.....

I'll keep points for a time, if just for the experience. I still hunt with a caplock muzzleloader for instance.

Maybe in the future I'd go over to an electronic setup, thanks for the info that I can keep my original distributor cap.

[rockyrivermark]

Originally Posted by Coley

....or keep your original distributor and buy and install a pertronix 'undercap' electronic ignition.
Thats a great investment...I have that in both my older trucks......and will never go back to points, lol.
The HEI is popular too but I don't want issues with clearance to the firewall or problems with my factory tach, etc.
It clears with a SBC no prob

Coley

Posted via Mobile Device

[In The Ten Ring]

Originally Posted by Coley

....or keep your original distributor and buy and install a pertronix 'undercap' electronic ignition.
Thats a great investment...I have that in both my older trucks......and will never go back to points, lol.
The HEI is popular too but I don't want issues with clearance to the firewall or problems with my factory tach, etc.

Coley

I tell you what Coley, on second thought, can you link me a good Petronix like you are talking about?

Also, I see these replacement "Flame Thrower" coils....can you link me one of those?

Do those new coils need an external condenser like my original has on its side? (My coil as a condenser on its side).

*My truck is bone stock under there, externally regulated alternator, 250 I6.

[Grumpy old man]

I don't think your problem has anything to do with the coil or dist , I'll bet a donut you just need a new set of points and resister installed correctly , just having the key in the on position for a short time can fry a set of points .

[garyd1961]

Have you set the gap in the points? Points work just fine if know how to keep them set. They require a lot of maintenance, that's why the HEI is so much better.

[Coley]

The Pertronix unit I've used in a couple of my V-8 GM's, including my current '72/350 is the Pertronix 1181 unit (you can always google this....and your local auto parts store probably has it in stock right now, or buy it off of ebay for $100, etc....easy to find)
I also replaced my coil this year...and you can go with either the stock unit or the high fire units...its up to you but both will work.
You just have to make sure that you either have or run a good solid voltage to the coil with the key on.
Remember....GM designed the ignition on these trucks to use points...so they 'built-in' some resistance in the original coil wire system to limit the voltage to the coil in order to not fry or degrade the points faster than necessary.
So that is why you have to test the amount of voltage you have to the coil with the original wires to make sure you have enough to run the pertronix.
....you may not have to.....I didn't originally on my truck and my pertronix worked well for years.
Do you have a multi-meter electrical tester and are you good at using it?

Coley

[In The Ten Ring]

Coley,

My dad is the tester guy.....he was a master electrician in a coal mine for 22 years.

He's supposed to come over later today with another coil and we are going to try some advice given here.

[RichardJ]

"In The Ten Ring", the very last thing you posted is that you're working on a 250 I6. That should be on the first post here as well as the other current threads you have going. You have guys telling you how to hold the fuel pump pin in a V8 and how much clearance a V8 HEI cap needs.


The "+" terminal on the coil should have something close to 12 volts when the points are "open". As the points are "open", there is no path to ground, so the voltage on the "-" terminal will be the same as the voltage on the "+" terminal.

Turn the engine until the points close. The points are then shorting the "-" terminal of the coil to ground. The voltage should now read about 1 Volt or less. The higher the voltage, the dirtier the point contacts are.
The voltage at the coil "+" terminal at this time will now be less than 12 volts. How much less than 12 V doesn't really matter.

The capacitor on the side of the coil, connected to the "+" terminal is for the Radio to prevent you from hearing ignition noise. There is another just like that one, on the external voltage regulator to keep you from hearing that noise in the radio.

If you have 12 volts at the coil "+" and the voltmeter tells you the points are opening and closing, it's time to check "Static Timing"

[In The Ten Ring]

Originally Posted by RichardJ

"In The Ten Ring", the very last thing you posted is that you're working on a 250 I6. That should be on the first post here as well as the other current threads you have going. You have guys telling you how to hold the fuel pump pin in a V8 and how much clearance a V8 HEI cap needs.


The "+" terminal on the coil should have something close to 12 volts when the points are "open". As the points are "open", there is no path to ground, so the voltage on the "-" terminal will be the same as the voltage on the "+" terminal.

Turn the engine until the points close. The points are then shorting the "-" terminal of the coil to ground. The voltage should now read about 1 Volt or less. The higher the voltage, the dirtier the point contacts are.
The voltage at the coil "+" terminal at this time will now be less than 12 volts. How much less than 12 V doesn't really matter.

The capacitor on the side of the coil, connected to the "+" terminal is for the Radio to prevent you from hearing ignition noise. There is another just like that one, on the external voltage regulator to keep you from hearing that noise in the radio.

If you have 12 volts at the coil "+" and the voltmeter tells you the points are opening and closing, it's time to check "Static Timing"

Why didn't they ask? It should go both ways. I assumed it wouldn't matter as I wasn't asking about HEI. They assumed I had a V8.....what is it with the V8 crowd? Do they never imagine some of us don't need to compensate? I'll go back and fix that though.

Interesting point though and thanks for telling me what the condenser on the side of the coil is for.....when I tested the lights a couple of weeks ago I found the radio would not come on....not even static. Could that indicate a problem with the coil & the condenser on its side?

[In The Ten Ring]

Originally Posted by Grumpy old man

I don't think your problem has anything to do with the coil or dist , I'll bet a donut you just need a new set of points and resister installed correctly , just having the key in the on position for a short time can fry a set of points .

I wouldn't have bet against you but if you want a doughnut I'll send you one.

Dad brought a testing light today and we had a better look at things. We got some conflicting info at times (by "info" I mean test results with his tester) but dad couldn't believe a coil would go bad. We also cleaned some on the coil wire to distributor with sandpaper. We had a look at the points, cleaned those with a nail file and re-gapped those.

SHE STARTED AND RAN.



Ran until she ran out of gas....I forgot to hook up the small gas can again. She ran on what fuel dad squirted into the carb and what was left in the line.

She ran a bit rough so maybe the timing or carb needs adjustment. She didn't seem to smoke any at all but did blow a considerable amount of rust out the tailpipe.

[VWNate1]

YAY ! .

Glad to hear you got it going .

If you don't yet have them, go buy dwell / tachometer and an inductive timing light, neither are very $pendy, Pawn shops for used, your FLAPS for new, should be under $50 each .

[In The Ten Ring]

I'll try and get those. I am sure to post new threads when I get into timing.

Very happy to have her going.

And I couldn't have done that without all the help in this thread and all the others. Thanks again to everyone.

['68OrangeSunshine]

Originally Posted by Coley

....or keep your original distributor and buy and install a pertronix 'undercap' electronic ignition.
Thats a great investment...I have that in both my older trucks......and will never go back to points, lol.
The HEI is popular too but I don't want issues with clearance to the firewall or problems with my factory tach, etc.

Coley

He's got an L6. Lots of room for the HEI distributor on a 250. 4WD V8s have the firewall/headroom issue.
I would get the points system going first, before the HEI transplant. I had a Pertronix and after 7 years it would cut out at freeway speeds [+3000 RPM, 60-65 MPH], went back to points for a year, then got HEI. My Autometer tach works just fine with all those systems.