73 valiant no spark from coil

-
Lowandslow

Lowandslow

Member
Joined
Mar 4, 2014
Messages
19
Reaction score
0
Location
Las Vegas
Hey guys I got a 73 valiant 4 door with 198 motor. She cranks but no spark from coil, only occasionally when I turn back to off position I get 1 late fire that causes a small back fire out of my intake. I replaced the ignition coil, ballast resistor, starter relay coil wire and ecu I'm racking my brain :banghead: :mumum::angry1::sad1: but can't come to a solution.
Here's a little list of things
-At the coil with the key in the on position the coil reads 4.3-4.8 volts when engine is cranked it only jumps to 8 volts- one problem
- Ballast resistor seems to be giving a correct resistance reading.
 
have you checked the pickup clearance ?it should be about .008/..010 checked with a brass feeler gauge. also checked the pickup coil resistance for a open in it.
 
67Dart273 said:
Low, you should never tag onto someone else's thread like this as it makes two "things" difficult to follow, but in this case this one seems to be dead, anyhow.

Some "stuff"

First thing to try is get yourself a clip lead and clip from starter relay battery stud (battery source) directly to coil positive terminal, and see if you have spark.

It is important to understand how Mopar ignition switches work. "Ignition run" or "IGN1" is powered ONLY in the run position, not start, nor accessory, and feeds power (among other things) to the ignition and alternator field, and dash cluster

THIS GOES DEAD in "start." The only ignition power for "start" (crank) comes from IGN2 or the "bypass" circuit. This is a separate switch contact in the ign switch which only goes one place-------out the bulkhead connector to the coil + side of the coil

IF the clip lead trick does not give you spark,

Remove the ECU from the firewall, scrape the firewall and ECU clean around the bolt holes, and remount, using star lock washers. The ECU MUST be grounded

Pull all connectors, the ECU, the resistor, the distributor, inspect with a light, and work in/ out several times. The distributor is especially fussy as there is no real current in that connector.

Check for spark right at the coil tower using a grounded probe, that is, eliminate even the coil HT wire.

Get yourself a .008" (inches not metric) brass feeler gauge. O'Reallys used to stock these. Check the reluctor to pickup coil gap in the distributor, and check it carefully for strike damage, play in the shaft, rust and debri sticking to the (magnetized) pickup coil.

With the key in "run" disconnect the distributor connector. I forget which one, so try both terminals. You can ground /unground one of the distributor pickup terminals and produce a spark each time. This shows the ECU is "probably" OK

Connect your meter to the distributor connector, on low AC that's right AC volts. Cranking the engine should "generate" about 1V AC

Check coil + voltage. With key in run, voltage at coil+ will be somewhere between 4 and 8 volts. If it's same as battery, something is wrong.

You have a tach? It should "jump" as you crank the engine. Or hook your multimeter or a test lamp to coil NEG. and crank. Light should go bright / dim meter should jump

Put your meter on coil + and crank the engine USING THE KEY. This should give you "same as" cranking battery voltage, and in no case less than 10V, the more the better.
Click to expand...

Have you tried a clip lead from battery to coil + HOW are you measuring this 8 volts cranking?

Measure from coil+ to ground while cranking USING THE KEY and NOT by jumpering the starter relay

If that is what you did, then you do indeed have a bypass circuit problem
 
is the rotor button turning? /6 uses a nylon gear on the distributor, if it breaks it won't start
 
Here are some checking points. Someone was nice enough to send me wiring diagrams for 73, which is the first year for the "new" style diagrams. These can be hard to follow without paper diagrams

The top diagram is the connector coming out of the steering column from the ignition switch

From the top

S2, a no 12 Yellow is the "start" wire, is hot in "start" and feeds through the bulkhead to the starter relay

Q2 a no 12 BlacK is hot in "accessory" and "run" and feeds power to the switched buss in the fuse panel

J2 a no 12 Dark BLue, is IGNITION RUN (IGN 1) and is hot ONLY in "run"

J3 a no 12 BRown IS THE WIRE which feeds cranking voltage to the coil. With the key twisted to start, this should be close to battery voltage, feeds out through the bulkhead, and to the coil + connection on the ballast resistor.

J1 a no 12 Red, is main battery power coming in from the bulkhead

The connections below that are not important at this time

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

SECOND DIAGRAM. Look at the top left contact of the ignition switch. THIS IS SHOWN incorrectly. The "START" contact feeding the yellow is NOT connected to the BROWN. THIS BROWN IS a separate contact isolated on it's own and NOT hooked to the yellow.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

BOTTOM DIAGRAM. Look at the bottom right of the page, find J3 14 BR coming in from the right. THIS IS the brown coil "bypass" circuit and this SHOULD be feeding "hot" voltage to the coil + in "start."
 

Attachments

  • connector.jpg
    42.4 KB · Views: 228
  • ignsw.jpg
    34.7 KB · Views: 188
  • ign.jpg
    72.6 KB · Views: 190
67Dart273 said:
Have you tried a clip lead from battery to coil + HOW are you measuring this 8 volts cranking?

Measure from coil+ to ground while cranking USING THE KEY and NOT by jumpering the starter relay

If that is what you did, then you do indeed have a bypass circuit problem
Click to expand...

I have not tried the lead from battery was going to try it when I get home from picking my daughter up at school, I'm getting the volts reading with the tester on pos and neg terminals on the ignition coil with key in on position it reads 4.7 when engine is cranked with key it reads no higher than 8 volts and only sends and occasional random spark when key is let back to on position from start. Not sure if I'm testing right that was on the volts test setting for ohms resistance it's hard to see what setting they have it on in the diagrams I.e. 200 20k 2000. I'm not the best with electrical but i can usually figure things out it's stumping me and thanks for the diagrams they are awesome
 
Lowandslow said:
I'm getting the volts reading with the tester on pos and neg terminals
Click to expand...

No Don't measure this way. Re-read what I posted

Clip the meter to GROUND (engine block)

Read from Coil+ to ground with key in "start."

Lowandslow said:
Not sure if I'm testing right that was on the volts test setting for ohms resistance it's hard to see what setting they have it on in the diagrams I.e. 200 20k 2000.
Click to expand...

Now sure what you mean? Either post a photo of your meter or the brand and model no. and we can advise on what settings to use.
 
Not sure if this has any relation with my prob but at freeway speeds it started running pretty rough the past week or so before she died. I thought it was my choke cuz my butterfly valve was open so I replaced that but it didn't solve my problem running rough problem fixed the valve though
 
My best guess. The starter along with a few other draws are using up your available voltage. When the starter draw stops, you get a spark. There is a huge wire supplying voltage to the starter. Everything else is attempting to operate on a much smaller wire.
Further reduce that supply at ignition switch contacts, various harness connections, etc.. and get the condition you have.
Couple places to look at... Look for a white engine harness connector. It has the alternator wires and others going through it. Its crap !
Look for a small white ceramic block with 2 wires. That would be a electric choke assist. Disconnect it. It is also crap. Neither of these were ever really needed. Chokes worked without the electric assist. Engine harness connector only eased assembly.
Good luck.
 
Lowandslow said:
This is the meter I have it's a innova 3306 here's a link to the image of it http://ecx.images-amazon.com/images/I/41A8oATzAxL._SS500_.jpg
Click to expand...

Closest destructions I could find are a 3300:

https://www.equus.com/Support/Manual

and the photo is so small, difficult to read, but some WARNINGS

The manual states "The DC 10 AMP range is not fused. Do not take longer than 15 seconds to take reading Wait 15 minutes between each reading"

What the above means, is if you are using the 10 amp current scale (left two probe jacks) that there is NO protection to the meter, and it is VERY "skimpy" built and will not truly handle that current. Be very careful taking current measurements

What you will be using most (right hand two probe jacks) is the top left YELLOW area which is DC volts. I cannot read, looks like 500? volts is max. "200m" means 200 millivolts or .2 (two tenths) of one volt

It appears there are only 2 AC volt scales, "reddish brown" at upper right. This is a very poor meter, but will likely get you by for automotive

Bottom left, the WHITE numbers, are continuity, resistance, ohms. Probably much of what you will check in automotive will be 200 ohms max. Lowest resistance, like switches, a good closed switch should read close to zero ohms, the lower the better. Something like 20K (20,000 ohms) or 200K might be used for things like checking plug wires.

The "arrow" symbol is a special position for checking diodes.

Don't use the "battery" positions unless checking 9V or 1.5V batteries.

So for tests we are discussing here use the YELLOW setting for the most part "20" which means the meter will display a max of 20V DC

Make these tests: Meter set in YELLOW, DCV on "20"


1............Turn the key to "run" and ground one meter probe. Probe around on your ballast resistor for the HIGHEST reading, which should be the two connectors which are looped together (You do have a 4 pin resistor is that right?) Post that reading

2............Clip the meter on ground, and to coil + Prop up the meter and crank the engine USING THE KEY. Read while engine is cranking. Post the reading.
 
Dude, I am lost reading the last 8 posts. Are we still talking about a 73 Valiant? Try this: remove plug the rotor is pointing at and set on valve cover with cable still attached. turn on ignition, Take a wire attached to negative coil terminal and drag it across the grounded clean metal surface, like the frame rail. does the spark plug fire a bunch of times, like a tazer? Coil check and ECU/ballast power to coil check. PAst that there is a way to do this off the ECU terminal too. Its the pin at 7:00 if you view the ECU with the transistor UP, opposite the missing pin if your ECU has only 4 pins.
 
I couldn't really tinker with I yesterday due to wild kids lol but I will be right under they hood I'll have an update ASAP thanks for all the help
 
67Dart273 said:
Have you tried a clip lead from battery to coil + HOW are you measuring this 8 volts cranking?

Measure from coil+ to ground while cranking USING THE KEY and NOT by jumpering the starter relay

If that is what you did, then you do indeed have a bypass circuit problem
Click to expand...

So I tried the lead from battery + to ignition coil +. I'm by my self so I had to bypass the starter but I cranked her and touched the lead to the coil pos and it gave a lil back fire so I'm assuming I have a spark when I do that. Does that eliminate or narrow down my problem
 
Well check the spark. Buy or rig yourself a spark gap. Many ways to do that
 
1............Turn the key to "run" and ground one meter probe. Probe around on your ballast resistor for the HIGHEST reading, which should be the two connectors which are looped together (You do have a 4 pin resistor is that right?) Post that readings = yeah 4 pin resistor. It's reading 10-10.8 on the two left pins and top right pin but only 5.6 on the bottom right the wire that goes to my + terminal on my coil.

2............Clip the meter on ground, and to coil + Prop up the meter and crank the engine USING THE KEY. Read while engine is cranking. Post the reading.[/QUOTE]
Ok so while the key is on and with the test done as directed this time it's reading 5.6 and when engine is cranked with key it goes to 8 volts
 
It didn't do the back fire when I cranked it with the key and used the jumper wire to the pos terminal on the coil
 
Voltage is WAY low. Either you have serious drop in the harness, or the battery is just plain dead

What does the battery voltage read when cranking?

Here's what you are up against, and why you need to crank using the key when testing for "real world" conditions:

The ignition switch has SEVERAL separate switches

The IGNITION RUN (IGN1) is hot ONLY in "run" not start

The BYPASS circuit, (IGN2) is hot in start, and is the only source of ignition to the system

The "path" that is the circuit path both these follow is:

From battery........fuse link.........through bulkhead connector..........to ammeter........through ammeter..........to ignition switch connector...........through switch........back out switch connector.........back out bulkhead connector..........to ignition system

If you have one or more bad connections in the above points, you will have VOLTAGE DROP to the ignition system.

Start by cleaning the battery terminals.

Measure battery cranking voltage right at the battery terminals. If you have less than 10V the battery is dead or going bad. A good battery which is charged will crank at 11V or so.
 
67Dart273 said:
Voltage is WAY low. Either you have serious drop in the harness, or the battery is just plain dead

What does the battery voltage read when cranking?

Here's what you are up against, and why you need to crank using the key when testing for "real world" conditions:

The ignition switch has SEVERAL separate switches

The IGNITION RUN (IGN1) is hot ONLY in "run" not start

The BYPASS circuit, (IGN2) is hot in start, and is the only source of ignition to the system

The "path" that is the circuit path both these follow is:

From battery........fuse link.........through bulkhead connector..........to ammeter........through ammeter..........to ignition switch connector...........through switch........back out switch connector.........back out bulkhead connector..........to ignition system

If you have one or more bad connections in the above points, you will have VOLTAGE DROP to the ignition system.

Start by cleaning the battery terminals.

Measure battery cranking voltage right at the battery terminals. If you have less than 10V the battery is dead or going bad. A good battery which is charged will crank at 11V or so.
Click to expand...

Yeah when cranked battery reads out 10.9-11.3 the battery is now drained I had recharged it last night but trying to crank it all day killed it again. Stating to think it's somewhere in my ignition switch or related problem seeing as how this is nearing the end of my list
 
Could be anywhere in the circuit path I mentioned, you must actually check it. Could be a COMBINATION of bad connections.

If the battery reads 11 when cranking that is not too bad. There should not be that much difference. Get this picture in your head. Re---read the circuit path and keep that "map" in your mind:

From battery........fuse link.........through bulkhead connector..........to ammeter........through ammeter..........to ignition switch connector...........through switch........back out switch connector.........back out bulkhead connector..........to ignition system

An easy way to check this is to "rig" an extension wire if need be.........Go to Radio Shack and get a baggie of clip leads. Clip one lead of your meter to the battery positive, like the starter relay stud

Now take the other probe with the key "in run" and check some of the points you can access on that circuit path. Check the bulkhead where the "ignition run" wire comes through the firewall on the inboard side. YES it is a beaouach to get to. An easy place to check is right at the ignition switch connector.

There are two ways to check

1------with the meter set up as above, with one probe on battery positive, you are DIRECTLY READING the difference in voltage. You are looking for a very low voltage, the lower the better. When you check the different points in the circuit path, this will show up as the drop reading changes. Ideally you want NO MORE than .3V..........three tenths of one volt

2.........with one meter probe GROUNDED and as you check each point along the path, the voltage will change. You will have to measure battery voltage and SUBTRACT the two readings to give you the difference. Just like in 1 above, no more than .3V
 
So I think I found the or a problem spot it in the harness that the wire from the coil goes into I attached a pic I'm reading 12 volts on the side from the bulk head at the fire wall and when connected it reads 5.6-6 volts same as on the coil it's self
 

Attachments

  • image.jpg
    66 KB · Views: 132
Yeah that looks like the typical engine harness connector. Even if its not the entire problem today it will only be a problem later. Delete it.
 
Lowandslow said:
So I think I found the or a problem spot it in the harness that the wire from the coil goes into I attached a pic I'm reading 12 volts on the side from the bulk head at the fire wall and when connected it reads 5.6-6 volts same as on the coil it's self
Click to expand...

I usually post this, but read this article. I'd say you are "in the zone." Don't forget what I told you. You could have ADDITIONAL bad connections, such as at the ignition switch connector.

Disconnecting and connecting connectors does not give you a picture of what is happening, however. You must check UNDER LOAD. When you disconnected the connector, you removed the load.

http://www.madelectrical.com/electricaltech/amp-gauges.shtml
 
You must log in or register to reply here.
-

Back
Top