Won't Start!

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Mbrown326

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I know alot of these get posted but here it goes...
Car started right up and ran fine for about 5 minutes and then just stopped. Engine will crank, but will occasionally try to start when I return key to run. I am getting power to coil when cranking and when in the run position.
I have checked coil, ecm, power to coil, and I disconnected distributor wire and tapped the harness end to ground with key in run position Just a buzz.
I have a 72 Dart with electronic ignition. It's a project and most things have been replaced. The distributor is a pre owned unit.
Any ideas? I replaced coil and tried old ecm ...no differance
 
Are you getting spark all the way to the plugs while cranking?
 
Last edited:
George Jets said:
Ignition
Compression
Fuel
Click to expand...
THIS

You have not said if you have spark, or have checked for fuel

COMPRESSION. You must have compression and enough. Sometimes you can wash down the cylinder walls with a lot of gas, especially on an older, worn engine, and reduce the compression so much it will not run. Run a compression/ leakdown check. ALSO is there any chance the timing chain has SLIPPED?

Fuel.....Must have fuel and FRESH. If this is a vehicle that sits a lot, do NOT assume that the fuel "will burn." Pump the throttle, look down the throat, use flashlight if necessary, and determine if accelerator pump is shooting fuel. Try a small "slurp" of fuel poured right down the throats CHECK THE PLUGS!! Are they dry or "normal" or FUEL FOWLED?

SPARK Must have spark, enough of it, and IN TIME. Again, is there any possibility that the timing chain has SLIPPED? "RIG" a wire of some sort COPPER, not RESISTOR to the coil tower with a gap, even a CLEAN spark plug. Prop it up so you can see it AKA through the hood gap, and crank USING THE KEY. Should have a nice blue snappy spark at least 3/8 and typically 1/2" long.
 
No spark coil or plug
Plenty of fuel in carb
It was running the other day and just stopped, no sputtering or popping.
 
Did you swap out your Ballast Resistor? Used to be the first thing to replace and usually fixed the "no start" condition.
Screenshot_20220704-133620_Chrome.jpg
 
In post #1 you said;
Mbrown326 said:
Engine will crank, but will occasionally try to start when I return key to run. I am getting power to coil when cranking and when in the run position.
Click to expand...
I post #8 you said;
Mbrown326 said:
No spark coil or plug
Plenty of fuel in carb
It was running the other day and just stopped, no sputtering or popping.
Click to expand...
Which is it?

Check your rotor, and make sure it is turning during cranking.
Also, check your pick-up coil for correct polarity, altho if it ran for 5 minutes, that should be fine. The pick-up should have One Orange wire , and the other, IIRC is black. If you have a violet and a gray wire, the pick up is wrong polarity.
I have had 318s that stopped running when all the teeth fell off the cam-sprocket; and as you say;
Mbrown326 said:
then just stopped.
Click to expand...
With any luck she's just flooded.
This should be an easy fix, unless the cam timing took a dump,lol.
 
If the ignition will not spark with the "tap test" then have you checked voltages to the coil and ECM? Is the ECM GROUNDED?

Check coil + voltage to ground with key "in run." Should be not much lower than 6 or 7 not much higher than maybe 9-10.

If it is at full battery, it means the coil is not drawing current---loss of ECM power or no ground at box, or open coil primary.

If it is in the range specified, re-check your "tap test." DO NOT use the coil wire. Rather "rig" a solid copper wire to a test gap
 
67Dart273 said:
If the ignition will not spark with the "tap test" then have you checked voltages to the coil and ECM? Is the ECM GROUNDED?

Check coil + voltage to ground with key "in run." Should be not much lower than 6 or 7 not much higher than maybe 9-10.

If it is at full battery, it means the coil is not drawing current---loss of ECM power or no ground at box, or open coil primary.

If it is in the range specified, re-check your "tap test." DO NOT use the coil wire. Rather "rig" a solid copper wire to a test gap
Click to expand...
I checked power at ECM. Looked good there. Coil + was good as well. I'll recheck tap tap test.
 
AJ/FormS said:
In post #1 you said;

I post #8 you said;
Which is it?

Check your rotor, and make sure it is turning during cranking.
Also, check your pick-up coil for correct polarity, altho if it ran for 5 minutes, that should be fine. The pick-up should have One Orange wire , and the other, IIRC is black. If you have a violet and a gray wire, the pick up is wrong polarity.
I have had 318s that stopped running when all the teeth fell off the cam-sprocket; and as you say;

With any luck she's just flooded.
This should be an easy fix, unless the cam timing took a dump,lol.
Click to expand...
Rotor is turning...
 
Do you spark at the plug? Use another plug and attach one of your plug wires to it and run a gator clip wire to ground from it. Crank it and see if you are getting spark. If not, check the mag pickup gap in the dist. Usually supposed to be 0.008". Sometimes things that quit as they warm up can be related to something a reluctor gap.
 
Mbrown326 said:
Thanks to everyone for there advice.
What would make it try to start when I let off key?
Click to expand...
THAT IS A CLUE

The key switch performs the ballast bypass function during cranking, there are two separate circuits

Double check by putting your meter from coil+ to ground, turn key to "run" and check voltage. Now hold the key to 'start' and read voltage. You should have "same as battery" during cranking. If not, there is an open either bad ignition switch, switch connector, bulkhead connector---or to the terminal at the ballast terminating to the coil+ wire

HAVE YOU CHANGED the ignition system wiring?
 
Mbrown326 said:
What would make it try to start when I let off key?
Click to expand...
The factory ECU gets it's power from ONE of TWO sources which begins at the Ignition switch. The DUAL ballast resister runs to the Ecu from the crank side during cranking, and to the ECU from the run-side when the key is released to run.
EDIT
OOPS , Del beat me to it.
 
When I checked voltage at coil when cranking it was battery voltage, dropped down when in "run" position.
 
Mbrown326 said:
When I checked voltage at coil when cranking it was battery voltage, dropped down when in "run" position.
Click to expand...
As I attempted to explain, the key provides TWO sources for ignition power

1.."In run" the dark blue IGN1 "run" buss feeds power under the hood to the ballast and ignition system, the VR IGN terminal, and any other (later years) component under the hood. Electric choke, smog doo dads, alternator field, etc

THAT RUN POWER GOES DEAD WHEN CRANKING!!!!!

2..."In crank" (start) the brown IGN2 which is a separate dedicated contact in the ign. switch, and comes alive ONLY during "start" feeds power to the coil+ side of the ballast. This feeds "hot" battery power to the coil, as well as "backfeeding" through the resistor to power the ECU.

So ONE MORE TIME

Key in "run" engine stopped: Coil + V will run "say" from about 6V to about 10V
Key in "start" engine cranking, coil + will run "same as battery."
 
Thanks to everyone. I double checked everything and decided to try a new distributor pick up. Started right up.
Hopefully there won't be any other gremlins for awhile.
 
If it was running, it is not incorrect p/up polarity.

Clue: dist unknown origin. If vac adv was used, the p/up wires may have broken from flexing. Measure p/up resistance while flexing wires, should be 150-600 ohms, with no change.
 
Mbrown326 said:
Thanks to everyone. I double checked everything and decided to try a new distributor pick up. Started right up.
Hopefully there won't be any other gremlins for awhile.
Click to expand...
I've had similar issues hence why I had suggested looking at the gap. Glad you found it!!
 
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