cranks but no spark at coil

[67Dart273]

Steve I did not read quite all of this. Your starter relay is different than your Cuda. On that relay, there is a terminal that provides fire to the ignition when cranking. Put your meter on coil+ and crank it with the key, you should have "same as battery."

If you have that, next turn the key to run, take the engine harness end of the distributor connector, and tap the bare terminal on a good ground. It should make one single "pop" spark each time you do that.

If those two things work, make SURE you clean the dist. connector, and if no joy I'd start looking for a pickup or other distributor.

Check reluctor gap?

Spin dist. with multimeter hooked to dist, on "AC VOLTS?"

 

[4spdragtop]

This distributor was in truck before and I believe the original one. As I mentioned I pulled it and put it into cuda to help diagnose a previous issue with cuda. Ran good in cuda, no issues. Get my replacement dist from Ray so pulled the truck one back out of cuda and set it on the bench.
I finally got my lazy *** around to outting it back in truck (awkward as fack in there!!). I checked and set reluctor gap to 0.008 with brass feeler gauge and reinstalled to same orientation.
I thought maybe I fd up on the reinstall but I checked TDC with piston stop and rotor pointing at #1 cyl and damper at 0* so all checks out there.

 

[4spdragtop]

Thats what I thought too. Fn thing. Thats when I thought coil wire may be bitched but I tried 3 lol.

Well, they should BOTH be sparking if You're doing it right, sparking where You tap the post & out the secondary tower thru the wire to the cap.

 

[Killer6]

The odds of two coils w/acceptable Ohm readings being bad are slim, but , lets see what tomorrow & a freshly charged batt. reveals, since Planet X has spared Us........
for now.......

 

[4spdragtop]

Thanks Del. Yes unfortunately the cuda and truck relays are different so no quick check/diagnosis there lol.
So test on coil +ve and the starter relay? Or coil +ve and ground? Will do that tomorrow and post results.
Reluctor gap I set to 0.008"
I never did a "spin test" with it out of truck. Worked when pulled so.....lol
So next test is everything hooked up, (except for distributor leads), key in rum and tap the bare end to ground and checking for spark correct?
Will do both tests tomorrow and post results.
If it was a quick distributor swap I would pull it lol.
Thanks again Del.

Steve I did not read quite all of this. Your starter relay is different than your Cuda. On that relay, there is a terminal that provides fire to the ignition when cranking. Put your meter on coil+ and crank it with the key, you should have "same as battery."

If you have that, next turn the key to run, take the engine harness end of the distributor connector, and tap the bare terminal on a good ground. It should make one single "pop" spark each time you do that.

If those two things work, make SURE you clean the dist. connector, and if no joy I'd start looking for a pickup or other distributor.

Check reluctor gap?

Spin dist. with multimeter hooked to dist, on "AC VOLTS?"

 

[4spdragtop]

Lol I agree, thats why im leaning starter relay?? But I dunno lol I skipped past

The odds of two coils w/acceptable Ohm readings being bad are slim, but , lets see what tomorrow & a freshly charged batt. reveals, since Planet X has spared Us........
for now.......

X" and now onto the "why"?

 

[67Dart273]

Here's how that works Steve. That "new fangled" starter relay has a separate contact that provides power to other circuits during cranking. Other than that one contact, the relay is the same functionally

From the top down:

The top left is the new added terminal. Electrically this one is the ONLY difference between old / new When the relay is engaged, this one feeds power out during starting to other circuits

The "twin" one top right.........This one hooks to BATT and is the same as your old "big stud"

The lower "twin" terminal..........This one feeds the starter solenoid power, and electrically is the same as your old one "square screw" terminal

The bottom two are the same as the old one............the coil terminals. One is getting cranking signal voltage from the ignition switch, the remaining one goes to the neutral safety switch (auto) or the clutch safety switch

 

[4spdragtop]

Ok cool cuz its a 7 blade but only 5 are used as there are only 5 female connectors that hook to it. So theoretically only 1 more as the cuda has 4 connections (I think)
So the coil +ve while cranking test. ...is that coil +ve to.ground with meter or coil +ve to a starter relay connection?
Sorry, not quite sure which way you mean.
Thanks again Del, electrical "babysitting" over the net has gotta be frustrating lol.
I appreciate all the help/input.

Here's how that works Steve. That "new fangled" starter relay has a separate contact that provides power to other circuits during cranking. Other than that one contact, the relay is the same functionally

From the top down:

The top left is the new added terminal. Electrically this one is the ONLY difference between old / new When the relay is engaged, this one feeds power out during starting to other circuits

The "twin" one top right.........This one hooks to BATT and is the same as your old "big stud"

The lower "twin" terminal..........This one feeds the starter solenoid power, and electrically is the same as your old one "square screw" terminal

The bottom two are the same as the old one............the coil terminals. One is getting cranking signal voltage from the ignition switch, the remaining one goes to the neutral safety switch (auto) or the clutch safety switch

View attachment 1715094405

 

[TrailBeast]

Thanks TB. So which contacts? Rotor to cap? Or distributor leads?
Not all the time but most times when I turn key off I get the "kickback" if that makes sense?

Distributor leads.

That makes total sense, because the coil field dropping (from the power to it shutting down when you turn the key off) causes a spark.
That's exactly what it should do and tells us that there is power to the coil.
The problem is nothing is telling the power to drop when cranking and the reluctor pickup coil in the distributor is what does that.
The distributor pickup coil sends a signal to the ignition module and the module shuts down the coil ground each time one of the reluctor vanes passes the pickup causing it to spark for each cylinder making the motor run.
This tells us that the either there is no signal coming from the distributor or the ignition module is not seeing it, be it because of a bad connection or bad part. (distr or module)

Do what Del said about touching the exposed connector of the distributor leads on the harness side to ground with the key on.
If you get a spark each time you tap that to ground that tells us that the ignition module works but isn't getting a signal from the distributor.

I like to crimp the two female sockets on the distributor pigtail just to make sure they are contacting.

 

[67Dart273]

Ok cool cuz its a 7 blade but only 5 are used as there are only 5 female connectors that hook to it. So theoretically only 1 more as the cuda has 4 connections (I think)
So the coil +ve while cranking test. ...is that coil +ve to.ground with meter or coil +ve to a starter relay connection?
Sorry, not quite sure which way you mean.
Thanks again Del, electrical "babysitting" over the net has gotta be frustrating lol.
I appreciate all the help/input.

You are trying to see if the coil is getting voltage. Just hook from coil+ to ground and see if you have voltage in "crank". Would not hurt to double check after key returns to "run" see that you have a lower voltage there, perhaps 7--10V or so.

Do you have a dual ballast? Does it appear the ECU is original? Could be trouble there. The "tap test" earlier should eliminate that

 

[Killer6]

Ok cool cuz its a 7 blade but only 5 are used as there are only 5 female connectors that hook to it. So theoretically only 1 more as the cuda has 4 connections (I think)
So the coil +ve while cranking test. ...is that coil +ve to.ground with meter or coil +ve to a starter relay connection?
Sorry, not quite sure which way you mean.
Thanks again Del, electrical "babysitting" over the net has gotta be frustrating lol.
I appreciate all the help/input.

Checking for voltage, simple as that, voltmeter from pink wire to batt neg post. Turn the key to start & crank, there should be Batt. V there.....it's that simple.......
there are voltage variations because of loads on the harness & draw from components, why I was telling You to unplug certain things...takes them out of the equation.
If You are checking this with the terminals plugged onto the ballast, the pink wire WILL have Batt. V~.5V in cranking postion, & 10-10.5V in Run position because Run
voltage will be coming through the ballast resistor.

 

[4spdragtop]

So the ECU is approx 3 years old, the orange mopar box, 4 pin. 2 post ballast
So battery ref volts is 13.02 (on charger all night). Cranking there were 11.7 V
Test voltage at ballast red wire (unhooked) and key in run 12.78 V

Test voltage at coil +ve with ECU unplugged and cranking. 11.93 V
Not cranking but in run 12.1 V

Test coil-ve ECU unplugged and cranking 10.9 V

Test dist lead (harness side). Male bare dist lead grounded I get spark from coil tower wire when held close to ground key in run position. Didn't do it before?? Or I did the test wrong??

Next has me baffled. Coil wire hooked back up to distributor. Key on and bare male dist lead(harness side) grounded, no spark from lead BUT I can hear one coming from somewhere, just cant pin point it.
Almost 100* out today. Friggin hot
Thanks all for the advice.
I posted a pic of the coil wiring. Manual doesnt show near the wires I have hooked to it (coil -ve) lol.
Good ground at ECU (continuity test)

Distributor leads.

That makes total sense, because the coil field dropping (from the power to it shutting down when you turn the key off) causes a spark.
That's exactly what it should do and tells us that there is power to the coil.
The problem is nothing is telling the power to drop when cranking and the reluctor pickup coil in the distributor is what does that.
The distributor pickup coil sends a signal to the ignition module and the module shuts down the coil ground each time one of the reluctor vanes passes the pickup causing it to spark for each cylinder making the motor run.
This tells us that the either there is no signal coming from the distributor or the ignition module is not seeing it, be it because of a bad connection or bad part. (distr or module)

Do what Del said about touching the exposed connector of the distributor leads on the harness side to ground with the key on.
If you get a spark each time you tap that to ground that tells us that the ignition module works but isn't getting a signal from the distributor.

I like to crimp the two female sockets on the distributor pigtail just to make sure they are contacting.

You are trying to see if the coil is getting voltage. Just hook from coil+ to ground and see if you have voltage in "crank". Would not hurt to double check after key returns to "run" see that you have a lower voltage there, perhaps 7--10V or so.

Do you have a dual ballast? Does it appear the ECU is original? Could be trouble there. The "tap test" earlier should eliminate that

Checking for voltage, simple as that, voltmeter from pink wire to batt neg post. Turn the key to start & crank, there should be Batt. V there.....it's that simple.......
there are voltage variations because of loads on the harness & draw from components, why I was telling You to unplug certain things...takes them out of the equation.
If You are checking this with the terminals plugged onto the ballast, the pink wire WILL have Batt. V~.5V in cranking postion, & 10-10.5V in Run position because Run
voltage will be coming through the ballast resistor.

 

[67Dart273]

Steve I would not have unplugged the ECU for coil voltage test. Hook everything "as normal." Measure coil + to ground in "run" and in "crank."

However at this point ---you have spark by grounding the dist harness---this looks to me like a dist / pickup problem

 

[Killer6]

Probably hearing the spark jumping inside the dizzy or cyl. since You are triggering a spark with the pick-up lead and the coil wire is back on. You've got enuff voltage that
it isn't the issue,& the starter relay is sending the system voltage cranking. They sell nice trailer harness cleaning kits now, can use them to clean the pick-up connections
nicely. As TB said, those molded dist. pick-up connectors let the socket terminals relax & open, close 'em up so they fit snug once their clean. A squirt of contact cleaner &
a little di-electric grease and You won't have to fool with 'em again unless the pick-up goes bad.

 

[Killer6]

I meant to ask if You have an analog Ohmmeter, even tho the dizzy just ran the 'cuda, well they just quit one day so............. hooking up said meter to the 2 leads on
the pick-up should make the needle fluctuate steadily & rhythmically when cranking, if You are using a DVOM w/a bar-graph it may show the same well enough..............

 

[4spdragtop]

Thanks guys. Going in to work tonight so tomorrow i will test coil +ve with everything hooked up. Hopefully temps drop a bit so cooler and easier to work on. Ill try n test before work. I will clean both sides of dist leads and recheck.
I may have to bite the bullet and pull distributor.
No to analog ohm meter. Cant I put digital one on "continuity" beep. And connect each probe to distributor leads (dist side) and it should beep while with cranking?
Not sure if I have a spare distributor to swap in.
Ebay has a starter relay for $10. I may order for a spare.
Thanks again guys.

Steve I would not have unplugged the ECU for coil voltage test. Hook everything "as normal." Measure coil + to ground in "run" and in "crank."

However at this point ---you have spark by grounding the dist harness---this looks to me like a dist / pickup problem

Probably hearing the spark jumping inside the dizzy or cyl. since You are triggering a spark with the pick-up lead and the coil wire is back on. You've got enuff voltage that
it isn't the issue,& the starter relay is sending the system voltage cranking. They sell nice trailer harness cleaning kits now, can use them to clean the pick-up connections
nicely. As TB said, those molded dist. pick-up connectors let the socket terminals relax & open, close 'em up so they fit snug once their clean. A squirt of contact cleaner &
a little di-electric grease and You won't have to fool with 'em again unless the pick-up goes bad.

I meant to ask if You have an analog Ohmmeter, even tho the dizzy just ran the 'cuda, well they just quit one day so............. hooking up said meter to the 2 leads on
the pick-up should make the needle fluctuate steadily & rhythmically when cranking, if You are using a DVOM w/a bar-graph it may show the same well enough..............

 

[TrailBeast]

Thanks guys. Going in to work tonight so tomorrow i will test coil +ve with everything hooked up. Hopefully temps drop a bit so cooler and easier to work on. Ill try n test before work. I will clean both sides of dist leads and recheck. (and crimp them closed a little)
I may have to bite the bullet and pull distributor.
No to analog ohm meter. Cant I put digital one on "continuity" beep. And connect each probe to distributor leads (dist side) and it should beep while with cranking? Nope.
Voltage should fluctuate around 1 volt when testing for AC volts while cranking, but testing continuity will only show a steady reading.
Not sure if I have a spare distributor to swap in.
Ebay has a starter relay for $10. I may order for a spare.
Thanks again guys.

Once you clean and crimp those contacts it will fire right up.
(Maybe) (should) from what I just read.
A new pickup coil can be gotten in most countries easily and cheaply.

 

[Killer6]

Thanks guys. Going in to work tonight so tomorrow i will test coil +ve with everything hooked up. Hopefully temps drop a bit so cooler and easier to work on. Ill try n test before work. I will clean both sides of dist leads and recheck.
I may have to bite the bullet and pull distributor.
No to analog ohm meter. Cant I put digital one on "continuity" beep. And connect each probe to distributor leads (dist side) and it should beep while with cranking?
Not sure if I have a spare distributor to swap in.
Ebay has a starter relay for $10. I may order for a spare.
Thanks again guys.

No, You will have continuity all the time, the resistance changes as the reluctor induces a small amount of current in the pick-up coil, this will be the signal the ecu uses
to switch the transistor. It is not an on/off affair, but a rhythmic pulsing in resistance....... if You have no continuity the P/U coil or one of it's leads is broken.

 

[67Dart273]

T

No to analog ohm meter. Cant I put digital one on "continuity" beep. And connect each probe to distributor leads (dist side) and it should beep while with cranking?
Not sure if I have a spare distributor to swap in.
Ebay has a starter relay for $10. I may order for a spare.
Thanks again guys.

No you want AC volts. Hook the meter to the two distributor leads on the lowest AC scale and "twirl" or crank the distributor. It should generate about 1V AC

I'm with TB....clean out the dist. connectors They are a problem Just "working" them in/out several times helps

 

[4spdragtop]

I had time to do a quick coil +ve volt check before work. Everything all hooked up and 10.9 V cranking.

Thanks for explanation on reluctor/pickup. Ill clean up the leads and give em a squeeze. If that no work, ill try the "twirl" on AC and see what that shows.
I will chk the local parts store and price out a spare pickup.
Thanks again all!

Once you clean and crimp those contacts it will fire right up.
(Maybe) (should) from what I just read.
A new pickup coil can be gotten in most countries easily and cheaply.

No, You will have continuity all the time, the resistance changes as the reluctor induces a small amount of current in the pick-up coil, this will be the signal the ecu uses
to switch the transistor. It is not an on/off affair, but a rhythmic pulsing in resistance....... if You have no continuity the P/U coil or one of it's leads is broken.

No you want AC volts. Hook the meter to the two distributor leads on the lowest AC scale and "twirl" or crank the distributor. It should generate about 1V AC

I'm with TB....clean out the dist. connectors They are a problem Just "working" them in/out several times helps

 

[4spdragtop]

Success...or so I thought. With everything hooked back up I was able to get it running....rough but running for about 3 minutes. Then it died and now no start again.
Dist leads were "snugged up" so good connection there
ECU was hit and miss with ground check. So I removed ECU and bettered the mounting surfaces/bolts. Back of ECU "looks" good.
I noticed red wire cracked in a few places, so I peeled back to the 4 way "welded splice". Red wire that's cracked is the one from ballast resistor. I will try to replace it.
Im going to attempt tests on 4 pin ECU while its out
Pics attached

 

[4spdragtop]

Ok ECU hooked up, key on, ground -ve coil at battery -ve, and coil tower wire, gives me NADA.
Exact same test with ECU unhooked and I get spark with coil -ve wire to -ve battery BUT again nothing at coil tower wire.
Im thinking ECU is toast. What do you think?
ECU is approx 3 years old and visually looks good.
Is there another test to verify its pooched?

 

[67Dart273]

Ok ECU hooked up, key on, ground -ve coil at battery -ve, and coil tower wire, gives me NADA.
Exact same test with ECU unhooked and I get spark with coil -ve wire to -ve battery BUT again nothing at coil tower wire.
Im thinking ECU is toast. What do you think?
ECU is approx 3 years old and visually looks good.
Is there another test to verify its pooched?

You lost me here steve

Hook everything up "normal."

1..Turn key to "run"
2..Measure voltage coil NEG to ground
3..Measure voltage coil POS to ground
4..Disconnect distributor connector, and tap the bare end of the engine harness side of that connector to ground. Should make 1 "snap" spark each time. IF THIS HAPPENS it is likely the distributor or that connector

 

[4spdragtop]

Sorry for the translation Del.
#4. When I run a wire and connect coil -ve to battery -ve and try for spark from coil tower wire to ground, I get nothing. Thats with everything hooked up and key on.
I repeat above test with ecu unplugged and I get spark BUT its coming from the coil -ve to battery -ve . Nothing from coil tower wire.
Fn intermittent ****.
You can see in pics the wires are a little shabby but none are broken, the plastic is brittle and falling off but wires show continuity.
#2. Coil -ve to ground 1.4V key on
#3 Coil +ve to ground 7.4 V(key on)

 

[4spdragtop]

Swung by the dealership and they had an ECU harness in stock. 5 pin/wire. Of course wires dont match in color dammit.
In order to replace harness, I gotta remove the bottom 2 red wires in the soldered/crimped 6 pack of red wires.
Getting them out and replacing them is proving to be a little difficult.
Is there a good 6 way junction/terminal bar that would be a solution?