No Start, No Spark trouble shooting suggestions

[Foxfire]

"A" won't start. This is what I've done so far.
Key off...power on both sides of coil
Key on...power on one side of coil
verified point gap and spark at points.
Key on and turning over the motor the AMP would move between - and +
checked and rechecked timing.
Checked filters in carb and firewall bowl. Carb filter was clean as was the firewall filter
Turned over with full choke. Gas in throat.

During trouble shooting did the following:
Replaced fuel line as ferule at the carb was back a ways from end.
Replaced carb with spare from Berts
Replaced condenser
Replaced coil with known good one.
Verified dizzy body was good by verifying continuity.

STILL NO CONTINUOUS INTERRUPTED SPARK

Took it to the club A mechanic. He hooked up his meter and firing light after verifying all connections and gaps etc.
With key on and turning over the light would fire once then nothing. After waiting a couple minutes we do it again. Same result. Light lights once then nothing. He also did a similar test at the points. When shorting the points he got one spark then nothing.

It's almost like there's a marginal wire that is broken or cracked but touching when cold then after a jolt of power opens until it cools down again?. THIS IS OVER MY HEAD AT THIS POINT. I'm heading over to his shop now to try again. The only thing we haven't done is take the popout out of the circuit although it appeared to be fine. The AMP was at 0 then -3/4 with popout on.

When I get back (it will be late) I'll post results if any. Hopefully I can post the fix. If not I'm open to suggestion of things we missed.

Stay Tuned.
Barb

[DaWizard]

It seems that there could be a rash of this happening, I had almost the exact happening with mine just in the last few days.

Change the coil, or at least hook up a known working coil.

Pull all the spark plugs, lay them on the head and from the left side, use the starter rod and starter to turn the motor over and watch the spark.

[Mitch]

[QUOTE=Foxfire;n9620]"A" won't start. This is what I've done so far.
Key off...power on both sides of coil good
Key on...power on one side of coil that's good if the points are closed. if they are open you have something grounding the circuit, lower plate wire, popout issue
verified point gap and spark at points. ok
Key on and turning over the motor the AMP would move between - and + ok
checked and rechecked timing. ok wont cause you to have no spark
Checked filters in carb and firewall bowl. Barb filter was clean as was the firewall filter ok
Turned over with full choke. Gas in throat. good your getting fuel


During trouble shooting did the following:
Replaced fuel line as ferule at the carb was back a ways from end. ok
Replaced carb with spare from Berts
Replaced condenser ok
Replaced coil with known good one. ok
Verified dizzy body was good by verifying continuity. what exactly did you ck here? continuity of the lower plate wire?? or the dizzy ground?

STILL NO SPARK (QUOTE)


where are you checking for spark? at the end of the coil wire to a head nut or at the spark plug?

are you operating the points manually and looking for spark at the end of the coil wire?

make sure your rotor is turning when cranking



every-time the points open and close you should flicker current on (points open) and off (points closed) at the red wire to the coil.. this will enable the coil to throw a spark.
sometimes moving the advance lever makes it connect since that moves the plate wire

My guess is an intermittent lower plate wire or a popout issue...

[Foxfire]

Mitch, I checked the "black wire" on the plate and tested continuity from the spark plug connectors to the rotor points inside the body. Rotor is turning. George has a cut off cap that's put on the distributor so the spark from the rotor to the cap point can be verified when rotating. He also had me work the spark lever up and down.

[Mitch]

to ck the lower plate wire you need to take it apart,, they are intermittent and may ck good with a meter

start by checking for spark at the coil wire to a head nut 1/4 gap or use a spark tester

[BILL WILLIAMSON]

In similar cases, the lower plate wire is usually the CULPRIT!!!---Takin' out the upper plate is NOT like takin' a dose of CASTOR OIL!!!
Bill W.

[H. L. Chauvin]

FWIW:

A. Going back to simple Vintage Pre-WWI gasoline engine auto repair in our rural area, after several tries of "Won't Start", these two (2) step, simple Vintage Mechanic's Tests were always recommended for "Quick" Preliminary Vehicle Gasoline Engine Diagnosis.

1. Turn ignition switch "Off"; rotate engine several revolutions; immediately afterwards, remove, look at, and smell tips of several spark plugs. "No" wet gas noticed indicates some sort of "Fuel Problem".

2. Next, turn ignition switch "On"; and with spark plug wires re-attached, lay spark plugs on sides to provide grounds for same, and rotate engine. "No" spark observed at spark plug gaps indicates some sort of "Electrical Problem".

3. However, "No" wet gas noticed, & "No" spark observed indicates some sort of possible "Fuel Problem" ............. and also some possible sort of "Electrical Problem".

B. Former Vintage Model A Mechanics had to diagnose problems "quickly" in order to earn a living repairing Model A's.

C. Appears today our modern Model A Restorers are recommended to waste time farting around all day for weeks with wires, points, condensers, coils, gas lines, a questionable distributor, "and" a questionable carburetor ............ in just trying to find if "Won't Start" is one of the many types of "Fuel Problems", or one of many of the different types of "Electrical" Problems".

Also hope this helps to find that not all Model A fuel problems are electrical ......... and vice versa.

[Patrick]

Points open, key on. should have 6 v
points closed, key on, no power at points
remove secondary coil wire and place 1/4" from a good ground
key on, open/close points, should have good spark



If you don't have spark as mentioned above, continue to look at primary circuit until you find the open circuit such as poor connection on primary lead to distributor, or, bad/worn primary wire between upper/lower distributor plate or bad ignition switch.

If you have spark as mentioned above, continue to look at primary circuit and see if you can make any lead go open, such as operating the spark lever [ upper/lower primary wire] or wiggle the primary lead going into the distributor [ famous for fraying/wearing insulation]. Also make sure ignition switch is good, once in awhile one will go open intermittently.


All that said, I think Mitch has found your problem.

[Foxfire]

I'm going to print all the responses and take them with. The only saving grace is the club "A" mechanic is stumped at the moment so I didn't embarrass myself with it being simple like the gas shut off etc.

I don't think it's a fuel issue. We used some starting fluid shot up the carb and it would not fire. Next will be to swap out the popout then the distributor.

[rustyrim]

If it sparks one time when you turn on the switch it means the points are always grounded. probably the armored cable. if you disconnect the armored cable from the distributor it should run..

[Tom Wesenberg]

A few years ago my 28 did something similar after setting during our humid rainy season. I'd stop the engine with the points open, then turn the key on and short the points on and off with a screwdriver, and the coil wire gave a good hot blue spark to a head nut. Try to start by using the starter, and it wouldn't go, so I'd clean the points contacts. I repeated this a few times, and the starter still wouldn't get it running.

I finally used the hand crank, and it fired right up. After it ran a few minutes, then the starter would fire it right up also. I would try hand cranking it, or push starting it.

BTW, have you had very hot, humid, rainy weather lately, like we've had in Minnesota?

[Foxfire]

I was only able to spend a short period of time at the shop as Mr. Mechanic had some visitors stop by. The next step is to remove the popout from the distributor and use the ignition jumper cable. The nut that holds the armored cable is not loosening up. It's time to try the candle wax trick. Monday will be the next work day on the A.

Tom, The weather has been unusually nice with low humidity.

[Mitch]

I'm sure your tech knows this but drain down the cooling system before loosening the head nut for the armored cable clamp

[BNCHIEF]

Mitch i never considered that thanks for the tip.

[Dennis]

I had a problem when I was starting mine for the first time and it was the wire from the ignition switch. Had spark at first and then no spark. Took the panel off and had spark and ran - and that was when the panel was hanging from the speedo cable. Looked at the wire from the switch and ammeter wires saw nothing. Put the panel back on same problem. Took it back off and looked close at the wire again and found the shrink tube was too short from the end of the terminal that was cheesy, and realized it was shorting out at that point. Cut the bad terminal off and crimped and soldered a new high temp terminal and shrink tubed it. Problem solved. I go to great lengths to find the terminals I use to replace when needed, they are much stronger than the cheepies. You might have a broken wire somewhere and those can be nerve racking too.

[Tom Wesenberg]

Since it was stated the amps move back and forth as the points open and close, that should indicate everything is fine from the coil to the points and ground. Once about 10 years ago I was helping on a pickup with a starting problem, and his ammeter moved the same way. The problem was the popout cable however, and it had a few broken strands of wire lightly touching the ground, so it was shorting to ground, but some current was also going through the points. This gave an occasional spark, but not consistent.

[Foxfire]

Well, here's the scoop. IT'S FINALLY RUNNING AGAIN. Went through the suggestion and here's what was finally found .

1. The intermittent spark was caused by the distributor and not the infamous black lower plate connector wire. The popout cable was screwed in but not quite far enough to provide a constant connection. After firing once it would loose continuity. After waiting for awhile it would do the same thing again, fire once then quit.

2. Compression was only 50 psi possibly caused by continued cranking (sucking gas in the cylinders) while trying to start it and test for spark etc. It was assumed that the gas stripped the rings causing the loss of compression. Oil was put in the cylinders and after running for awhile and quit smoking the compression came up to 95. It's a newly rebuilt B engine with B high compression head.

I'm surprised I was able to put 58 miles on the car before it went into storage for the winter. I think I have a resident garage ghost that likes to play tricks and unscrewed the cable just a little.

[Mitch]

thanks this will be a good thread to help others with all the suggestions and tests.

[tbirdtbird]

glad you solved the problem, but what led you to determine the cable was not screwed in far enough?
Intermittent problems are so nasty......

[Foxfire]

I mentioned to George that the only thing we hadn't changed was the dizzy. He said he was ahead of me on that but it will take a couple days since the nut holding the cable was not cooperating and he didn't want to be faced with a broken stud. I got a call 3 days later and heard her running over the phone. When he finally pulled the dizzy out and went to unscrew the cable it didn't seem tight so gave it another twist and put it back. TAH DAH a running engine. I had a problem once where the cable was too tight. I love how simple the model A is. LOL

[Jm29henry]

Good to here that is running again

[Chuck Sea/Tac]

Weak primary equals weak spark. George and I were talking on the phone, just after discovering the poor distributor connection. The engine would run for a few seconds on ether, but not on gas, because of the difference in ignition temp. Which could make you think it's a fuel problem, but actually a weak spark. The plugs seemed to fire when laid on the block fine.
what a tricky one.