MDchanic

You need to understand how the ignition system works, and then troubleshoot it systematically.

As this question comes up many times per month, I am finally motivated to do what I've been threatening to do for a while now, which is to scan in the excellent ignition troubleshooting directions from my 1965 Glenn's Manual, so here it is:

"IGNITION SYSTEM

The ignition system furnishes the electric spark which fires the mixture. Absence of a spark, or a weak spark, will cause starting trouble. Ignition troubles should be isolated by logical testing. For this purpose, the system is broken down into its smaller circuits: The primary and secondary. Each of these should be broken down further and individual components tested separately.

To Test the Entire Ignition System.

• Remove one spark plug wire and hold it about ½" away from the base of the spark plug or any metallic part of the engine.
• Crank the engine with the ignition switch turned on.

A good spark from the wire to the metal means that the entire ignition system is in good working order.
No spark, or a weak, irregularly occurring spark, means ignition trouble, which must be traced by the following tests:

To test the Primary Circuit (Test 1).

• Loosen the distributor cap rationing bails and move the cap to one side.
• Remove the rotor.
• Turn the engine over by means of the fan belt or starting motor until the contact points close.
• Turn on the ignition switch.
• Remove the high tension wire leading to the center of the distributor cap;
  this is the main wire from the ignition coil which supplies the high voltage to the rotor for distribution to the spark plugs.
• Hold this wire about ½" from any metallic part of the engine.
• Open and close the contact points with a screwdriver.
• Hold the distributor against the moveable point only as shown.

A good, regularly occurring spark from the high tension wire to ground means a good primary circuit and a good ignition coil.
No spark, or a weak or erratic one, from the high tension wire to ground means primary circuit trouble or a bad ignition coil.

To Test the Ignition Contact Points (Test 2).
To test the condition of the ignition contact set,

• turn the engine over with the fan belt or starting motor until the contact points are separated.
• Slide the screwdriver blade up and down, making contact between the movable point and the bottom plate of the distribute, as shown.
  You are now using the screwdriver tip and the bottom plate of the distributor as a set of contact points.

A good spark from the high tension wire to the ground, after having had no spark in Test 1, means that you have a defective set of contact points.
No spark, or a weak one, means primary circuit trouble, other than the ignition contact points, or a bad ignition coil.

To Test the Condenser (Test 3).
A shorted condenser can be checked by noting in the previous ignition contact point test (Test 2), whether or not the tip of the screwdriver blade sparked against the ground plate as it was slid up and down.
No spark at the tip of the blade means either a shorted condenser or a break in the primary circuit.

This can be checked further by

• disconnecting the condenser case where it is screwed to the distributor
  (do not disconnect the condenser wire lead).
• Hold the condenser so that its case does not make contact with any metallic part of the distributor.
• Repeat the test of moving the screwdriver blade up and down while holding it against the movable point.
  Be sure that the contact points are open while making this test.

A spark at the screwdriver tip now, which was not present with the condenser in the circuit, means that the condenser is shorted out.

No spark at the screwdriver tip with the condenser out of the circuit means that there is an open circuit somewhere in the primary. Check the small wire lead from the primary terminal to the movable contact point. This wire lead sometimes [breaks] under the constant flexing of [the] operation [of the centrifugal advance mechanism].

To Test the Secondary Circuit (Test 4).
The secondary circuit cannot be tested until the primary circuit is functioning perfectly. If the primary circuit tests good, or after the necessary repairs have been made to the primary circuit, then the secondary circuit can be tested.

To test the secondary circuit,

• turn the engine over until the contact points close.
• Then turn on the ignition switch.
• Hold the main high tension wire (from the center terminal of the distributor cap) about ½" from any metallic part of the engine.
• Open and close the contact points with a screwdriver blade held against the movable contact point only.

No spark, or a weak one, from the wire to the block (with a good primary circuit), means a bad ignition coil or a defective main high tension wire from the coil to the distributor (especially where it runs through metal conduit).
A good spark here (with no spark to the spark plugs) means that the trouble must be in the distributor cap, rotor, or spark plugs. It is seldom that spark plug high tension wires (unless obviously rotted) will keep an engine from starting.
To check the main high tension wire, from the coil to the center of the distributor cap, replace it with a new piece of high tension wire, or remove the old wire from the metal conduit and repeat Test 4 while keeping the suspected wire away from any grounded surface.

To Test the Distributor Rotor (Test 5).
Test the distributor rotor by replacing it on the distributor shaft and holding the main high tension wire (from the coil) about ¼" from the top of the rotor.
With the ignition switch turned on, crank the engine with the starter.
If the high tension spark jumps to the rotor, it is grounded (defective);
if not, the cap must be defective. Inspect the cap for carbon tracks which indicate the passing of high voltage electricity."
from: Glenn's New Auto Repair Manual, by Harold T. Glenn, Chilton Books, Phila, PA, 1965.








All of the above from: Glenn's New Auto Repair Manual, by Harold T. Glenn, Chilton Books, Phila, PA, 1965.



Image above a composite of page 2-460 of Motor Auto Repair Manual, 37th Edition, Ed. Louis C. Forier, S.A.E., Motor Books, New York, 1974

- Eric

MDchanic

This post is a placeholder to hold the remaining images.

oldcutlass

Made this a sticky, thanks for the contribution Eric.

MDchanic

Why, thank you , Eric. I'm flattered.

- Eric

oldcutlass

Simple wiring diagram, disregard some of the wire colors.

Toro X6

This is great information, and I'd like to add my 2 cents... Don't forget there's a ground circuit from the breaker plate to the distributor body and through the holddown clamp/bolt to the engine block. High resistance in that part of the circuit will limit coil current which will limit coil output (secondary) voltage too.

MDchanic

Absolutely true, Toro.

A common manifestation of this is when the tiny ground wire from the points plate to the distributor body is broken, causing intermittent stalls, as the points plate loses contact with the body under certain circumstances.

Welcome to ClassicOlds.

- Eric

tkheld

Eric,

I have been having a intermittent stumble issue with my 67 Cutlass. i have replaced every part of the ignition system with no luck Could the problem be the distributor ground wire? After reading this post, I checked mine and it is loose where it is crimped to the points plate. I have no idea how to remove and replace this wire. Can I run another ground wire from under the screw that attaches the points to the plate?

Thanks,
Tim

MDchanic

Good question.

Yes, it could be.

That wire should definitely not be loose, and it should have good continuity.
If you can provoke the stumble by moving the points plate (by sucking on the advance line and releasing it), that would prove it, but even if not, that wire should be secured.

The wire can be replaced with any wire of comparable dimensions, but it should be a wire with unusually fine stranding, to make it as flexible as possible.

A wire under a points attaching screw should not be bad, so long as it doesn't interfere with anything else, but you could probably solder a wire to that crimp point with a bit of skill and the right flux.

- Eric

tkheld

Ok. So I added another ground wire. Car is running but the stumble is intermittent so only time will tell.

Also, do you know if there is anything unique about the black coil to distributor wire? Can that be replaced with a standard copper wire of the same gauge?

MDchanic

It is also unusually fine, and unusually flexible, because it needs to move freely with the points plate.

- Eric

pcard

Hi Erics: I have a Breakerless SE ignition and wanted to put together a procedure for diagnosing this system. While doing it I thought to incorporate the CSM procedure for the points system as well.

Considering that this may not be done under cover, and physical access to my distributor innards is limited due to a bad back, I thought to try to do simple tests first. Another consideration was that I would assume that I have done my regular maintenance and at least the plugs and wires would be fresh and clean, and so I started at the other end of the ignition circuit.

I put together the attached and would appreciate your critique. I know it looks intimidating and understand if you guys do not have time to go through it.

I plan on testing it out when I do my spring dust off.

Oh - for reference I also have a starter relay circuit installed

Here is a link to the Breakerless SE troubleshooting guide:
http://www.breakerless.com/techhelp.htm#After installing the Breakerless SE, my engine won't start?

MDchanic

That's a helluva chart. Unfortunately, on my computer, in OpenOffice, it only opens up as a large number of pretty flowchart shapes with no words inside them.

Looking over the instructions for the electronic ignition unit, it appears a bit more complicated to install than the Crane or Pertronics III units - I'm curious as to why you selected that particular model?

Are you having a problem with your ignition now, or are you just preparing in case you have a problem later? (And, are you an engineer?)

- Eric

pcard

Hi Eric: I have attached a PDF. I tried an Open Office ODS file, but the site does not allow it. I can send one to you separately via email.

Nope, I was never an engineer, just a physicist. I did like to get my hands dirty on the lathe but the engineers would shoo me out of the lab if I got too involved. They were afraid I would break something. They were probably justified.

The reason I went with the Breakerless SE is I wanted something that would use the stock distributor, coil, and wiring. This only uses the one distributor primary lead.

oldcutlass

I didn't go through the flow chart with a fine tooth comb, it looks like it covers all the bases. I don't think the compression check portion is necessary.

MDchanic

Yes, looks very comprehensive.

I'll need time to look at it more closely.

- Eric

pcard

Hi Eric: I put the compression test in there because it is in the CSM chart, and I needed an escape condition.

MDchanic

Me, too.

I'd been hoping mine would be winning the lottery, but now I'm beginning to lose faith...

- Eric

oldcutlass

Me too...

pcard

I just noticed a problem in my chart: at times I call for cranking the engine with the Ignition in the Off position. ( using the remote starter ). That would be really bad for the ignition switch and solenoid.

MDchanic

Not really. Shouldn't hurt anything.
It's common when you want to move the engine, but not have it start.

- Eric

oldcutlass

Unless you looking for spark or B+, the switch would need to be on.

pcard

Hi Eric:
I thought the Ignition Primary is grounded at the Ignition Switch when the Switch is in the Off position. Wouldn't this mean that the Coil Positive (+) terminal is also grounded?
If that is the case then while cranking with a remote starter, with the Switch in the Off position, the 12 volts from the yellow bypass wire is going directly to ground through the ignition switch via the Resistor Wire.
Is that correct?
Is so, wouldn't that damage the Ignition Switch and possibly the solenoid?

oldcutlass

The ignition switch provides voltage to the coil in the on position. When its off its open, no voltage. The ground you may see is through the points on the coil- side.

MDchanic

Not to my knowledge.

I don't have an ignition switch in front of me to test, but I do not believe that any of the ignition switch contacts is grounded at any time, other than the one wire that goes to the temperature sender and the temperature light, which is grounded in the START position so that the light lights while cranking, so that you can see that it works.

- Eric

pcard

The attached is from page 6C-5 of the 1970 CSM.
Is this one of the errors in the manual?

oldcutlass

I can see disconnecting the hi voltage lead from the coil to the distributor. I'm not sure about the ground in the ignition switch and can see back feeding voltage through the coil+ junction back through to the ignition switch. I've always assumed it as either open or closed supplying power through the pink wire. Have not found a picture of the internals of the ignition switch as of yet to verify. On a side note the car can start with an aux switch because of the bypass wire feeding the coil +, but will stop one power is removed from the solenoid. Disconnecting the coil wire prevents this, however I've never grounded it. With an HEI you have to pull the Batt+ power plug if your using the bypass wire during start.

Oldssupreme

Great thread Erics! Thank for all the great info that you two have posted here!
chris

MDchanic

You're welcome!

I'm glad it's been helpful.

- Eric

classicmuscle442

Excellent thread, lot of good info, thanks for taking the time.

Supreme455

Now if I could just get one of you to stop by and get mine to start

My 1970 Cutlass Supreme 455/400 has just been sitting in the garage for over 2 years now because after all these years it decided it didn't want to start (never had this problem since I got it in 1979)

I am a bit older than the car and nothing is easy to do these days.

The main thing is I see no spark (doing this by myself since the wife won't help by looking at the spark as I turn over the engine)

As you know there isn't much as far as how the ignition works and it probably will be the coil even though it is not that old.........my luck I got a bad one (and the regulator is also new) and the alternator worked last time it was running (I just got a new battery since the one I had for my garaged cars finally croaked)

I did try to see if I could get spark by connecting another 12 volt coil I had but that made no difference.........but then I have no idea if that coil is good either)

It is the original distributor and I don't have any idea when the last time I changed the points but it probably has been over a decade.

I can't even get the damn coil out since I can't get a wrench on that bolt that hold it down (I'm sure you all know how that is)

I did even buy an electronic ignition distributor from Summit Racing but I figured I better not even try removing the original and installing this one since as you know it is not the same as a Mopar where it only goes in 2 ways (I did that on my Power Wagon several years ago)

I figured I would get that gear screwed up and she would be out of time.

I wish I had a mechanic around here that made a house call.....and I sure won't have it towed to one since they charge hundreds of dollars around here to do that.

The reason I always liked this car was they are all the easy basics..........hell if I open the hood on my 1999 Chrysler 300M all I see is wall to wall metal and plastic

BUT then I never did expect the day when I would be the old geezer who could only change oil and spark plugs on a perfect day.

Now winter is on its way and I can only hope turning over the engine will move oil around enough (full tank of gas that is getting a bit old and I probably should have just used it for my lawn mower this year)

Just thought I would stop by here since it has been a while and you guys are fellow Oldsmobile junkies (why the hell did they decide to keep Buicks on the production line but NOT the Oldsmobile the original American car?? )

Still have this new distributor in the box sitting on the stairs so I see it every time I walk up to check my computers.

Hell I have wanted to do a few other things over the years but when I can't even start it and drive it outside once or twice a year ......it just sits there

Fun71

I would start by looking at the points to make sure there isn't something obviously wrong with them, such as a loose mounting screw, black and burned up contacts, corroded contacts, spider web in the gap, etc.

Supreme455

Yeah I may give that a try since I did get a light plugged in down in the garage last time I tried to start it up.

I have a couple other problems and one is that there is not much room since the garage is full of 35 years of my collections and another car and the John Deere so it is hard to just reach in from the passenger side (no room on the other side) and I can't reach back there or see there from the front.

I also have a back problem that usually gets better but this time it is not so I won't know if I can get the cap off and get a decent look at the points and see how they look or if they just need a piece of sand paper or if they are stuck closed.

My luck is more likely I will get stuck laying over the front fender until the wife finally wonders where I am

Sure would be great just to start it up and then drive to a mechanic and have them put in the new electronic ignition since I have wondered how that would run after all these decades using the original one.

But then it is the rainy season here so it would be nice just to fire it up and run it sitting in the garage just to warm up the oil again.

Thanks for the suggestion

MDchanic

The points are probably slightly corroded and not passing current.

That being said, the only way to know is to check, and the only way to check is to take off the distributor cap, get a test light, have a spare set of points and a dwell meter handy, and follow the procedure on this page, which will isolate the problem in short order.

If you can't get the cap off and lean into the car yourself, you'll have to get someone else to help you - friend, neighbor, paperboy - somebody.

And, honestly, you'll have a much easier time with the car (or at least the nose) out of the garage. If you can't push it out, can you tie a tow strap to it and pull it out?
Once it's in the open, you'll have an easier time.

Good luck! You'll find the problem if you look for it.

- Eric

Supreme455

Yes I'm sure you are right MD

This car has always been babied and only came out in the summer and always started right up and I would start it several times in the winter to warm her up and get the oil moving around especially when the temp. got down below freezing.

That is why it was strange that it decided not to start.

Now as far as the rest......no neighbors here (I live out in the country on the Olympic Peninsula) and the neighbors closest to where I live are over 80 years old.......no paper boys either lol ......I have lived here on this property since 1984 and everyone I know moved away years ago (email these days)......as far as the garage......well it is parked nose in first and it can't be rolled out since it goes from concrete to grass where this time of year it would get stuck and then it would not get back in until next summer when the ground was dry and hard again.

It was always tricky driving getting it in the building and I would never let anyone else try that since there is only about 2 inches on each side inside the garage (wall on one side and a support beam on the passenger side .....long story but it ain't easy parking her in this old building.

So I am going to give it another try and get the cap off and try to get the light close enough and try to see if I can get a look at the points.

It is still strange that it ran fine when I parked it at the end of the summer and then the next time I try to start it I get no spark.

No mechanics around here that would do anything unless I make an appointment AND drive it in.

Not to mention I couldn't leave that car with anyone.

Charlie Jones

This has always been my recommendation as a professional mechanic .
New points every 10,000 miles . Or once yearly , in the spring , if you didn't drive 10,000 miles .

oldcutlass

While points are still relatively inexpensive, I recommend an inspection and recalibrate rather than replace every year. When I run points I do no parts tuneups twice a year and replace them when I feel they are no longer serviceable.

Supreme455

Well guys it is a nice day here so I got down to the garage (275ft away from the house) and decided to see what I had under the distributor cap

One thing I noticed before even doing that is that the condenser looks prehistoric and I guess when I installed that coil years ago I used the same condenser.

I don't know the name of that part under the rotator but it is a pain in the *** in the way metal thing.

So I bring a file with me for the points and when I open it up......yeah they look burned.

And the file did nothing to the contact that you can see looking at the points.

I of course always heard guys say to change them after certain miles or time but I never did that and as you know a 1970 455/400 is a rare factory engine that can still go 120mph UP a steep hill (I did that last time it was on the road since we always used that as a contest on our way to the golf course)

Well I retired from playing golf about the same time the car decided not to start.

It definitely sucks not even being able to fire it up just to warm her up and I even hope my Flow Master isn't rusted on the inside from sitting 3 years (used to always happen when I had the cheap exhaust installed before that)

I may have found a mechanic (haven't actually talked to him) and he hasn't done this for years and is actually the guy who does the repairs and maintanance at the hospital in town.

NOW I wonder if I do get him out here if I should just have him install that electronic distributor I got from Summit Racing.

What do you guys think about this?

Of course I would save the old one and add it to my parts bin.

This is one of those rare time where I wish that was as easy as a Mopar 318 and had the distributor up front like one of those.......found on road dead cars

IF I do get her running so I can get her outside next summer I want to do some upgrades on the old garage so it isn't as hard getting in and out........would like a concrete slab to back out on but hell I know how much that would cost even if I did all the work (I have mixed over 5 TONS of concrete on my property over the decades to make things and just for some Masonry fun )

My next project would be replacing the damn radiator so it has a full core version and the original was removed decades ago......not sure if that original is still around here (yeah I have too much stuff stashed here)

oldcutlass

Your next project may be getting the old gas out of the tank if it smells like varnish. If you don't it will gum up your carb and possibly other things.

Supreme455

Yeah that might be a good idea and I am pretty sure it is full almost up to the cap since I last filled it in......maybe 2015 ....hell I forget the last time I had her out on the road now.