cranks but no spark at coil

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4spdragtop

4spdragtop

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Hi, hoping for guidance. Ive tried/cursed and researched several days now.
Its on my 84 360 Dodge D150.
I "borrowed" distributor from truck for the cuda to diagnose an issue I was having woth cuda.
Cuda problem solved and truck sits for 6-8 weeks (if not more) before I get the distributor reinstalled in truck.
A simple but very frustrating/awkward/cursing adventure.
I noted orienation of rotor and vac can prior to removal and reinstalled to same orientation.
Now I can't get spark from coil.
I tested 2 coils and with both i got 9K ohms on coil center post to either outside terminals.
So I assume coils good?
Ohmd the ballast resistor(and a spare one) unhooked and got 1.2 ohms approx.
So I assume good?
Ive done LOTS of continuity tests lol cuz the "beep" makes me feel good.
Cranking engine gives no spark from coil but when turning key off it seems to wanna start.
Factory elec ign 360 4 bl auto.
Thanks! I have meter and factory manual.
Thanks
Steve
 
Ballast will do that trick of wanting to start when turning key off. Other trick is ignition. Spray and clean tumblers or replace.
 
Tried 2 different 2 pin ballasts. Ohmd both at 1.2 which I believe is within spec.
Tumblers?? Are you talking ign switch?

Thanks
QKFSH67 said:
Ballast will do that trick of wanting to start when turning key off. Other trick is ignition. Spray and clean tumblers or replace.
Click to expand...
 
4spdragtop said:
Hi, hoping for guidance. Ive tried/cursed and researched several days now.
Its on my 84 360 Dodge D150.
I "borrowed" distributor from truck for the cuda to diagnose an issue I was having woth cuda.
Cuda problem solved and truck sits for 6-8 weeks (if not more) before I get the distributor reinstalled in truck.
A simple but very frustrating/awkward/cursing adventure.
I noted orienation of rotor and vac can prior to removal and reinstalled to same orientation.
Now I can't get spark from coil.
I tested 2 coils and with both i got 9K ohms on coil center post to either outside terminals.
So I assume coils good?
Ohmd the ballast resistor(and a spare one) unhooked and got 1.2 ohms approx.
So I assume good?
Ive done LOTS of continuity tests lol cuz the "beep" makes me feel good.
Cranking engine gives no spark from coil but when turning key off it seems to wanna start.
Factory elec ign 360 4 bl auto.
Thanks! I have meter and factory manual.
Thanks
Steve
Click to expand...
You have no power at the brown wire to the coil side of the ballast, why is what You need to find out. Check for B+V at the column connection, both sides, same at the
bulkhead on the firewall. Just unplug the starter relay so You can hold the key in the crank position while You check...................

Oh POOP!, not the 'cuda the tk.................well nevermind! Same prob., diff. wire colors/routing :)
 
Last edited:
Coil +ve is a single pink wire that runs to ballast, where it joins another pink wire.
Opposite side of ballast is red wire
Killer6 said:
You have no power at the brown wire to the coil side of the ballast, why is what You need to find out. Check for B+V at the column connection, both sides, same at the
bulkhead on the firewall. Just unplug the starter relay so You can hold the key in the crank position while You check...................
Click to expand...
 
So a few tests. This one pictured no spark. I also tried same test with -ve coil grounded to battery and output wire 1/4 inch from ground. No spark at output wire BUT the ground wire from coil-ve was sparking at battery -ve ???

20170923_162444.jpg
 
Forgot to mention all tests with key in ON position.
Voltage at coil +ve and battery -ve 8.71V

Coil resistance. -ve to +ve posts 1.2 ohms
Center post to either -ve or +ve terminals 9.63K ohms.
 
4spdragtop said:
So a few tests. This one pictured no spark. I also tried same test with -ve coil grounded to battery and output wire 1/4 inch from ground. No spark at output wire BUT the ground wire from coil-ve was sparking at battery -ve ???

View attachment 1715094132
Click to expand...
Ok, first, the batt. should be at 12.75V, the Red wire should be ~.5V less at the most w/the key in run position unplugged from ballast.
The "other" Pink wire not going to the coil should be going to the Ign sw. cranking terminal, again,~.5V less than Batt.V with the key in crank position unplugged from ballast.
That "Pink" wire runs to the starter relay? Unplugged from the ballast it should only have B+ w/the ign. sw. in the cranking position.
Yes, the wire from Coil Neg. is going to spark, You're grounding the primary side of the coil......but Your supposed to be tapping that wire to ground, mimicking points &
watching for spark out of the coil wire.
Most modules won't operate below 9V, if the Batt. is that low with just the key on, it may be dropping out cranking for sure...........................
Forgot.....'84....could run in to ign.sw. or to starter relay..............what say the
diagram?
 
Last edited:
Had the symptoms years ago same situation I cleaned the terminals and then it started and ran perfect. Sounds to simple but just thinking out loud
 
Check you distributor connector Steve.
I have seen those contacts inside them spread open and not make contact.
If they don't make contact then nothing tells the box to fire the coil.
Since it fires when you turn the key off you know it has power available.
It sparks when you turn the key off and that is what the igntion box does, (shuts the ground to the coil off momentarily to make the coil fire) so that pretty much narrows it down.
 
Ok ill try and answer/post results in order of how they were posted here.
Family dropped by so had to drop tools for the night.
Killer6, the battery voltage was approx 12 ish. Its a little low due to me constantly trying to start it with no success. So charger is on it now.
I will chk tomorrow for voltage drop of 0.5 V at red wire on ballast.
Other pink wire (non coil one) on ballast leads to 7 blade starter relay.
I didnt chk voltage but did chk for continuity and it shows continuity.
What do you mean "B+ while cranking"? Not sure what you mean sorry.
I understand the sparking from coil -ve when grounding but the wire that is supposed to spark (coil wire from center) is NOT sparking, no matter how close to ground I hold it. Strictly the one from coil -ve to battery -ve .
Not sure which wire you are asking about as per schematic?
Thanks for the help!
Killer6 said:
Ok, first, the batt. should be at 12.75V, the Red wire should be ~.5V less at the most w/the key in run position unplugged from ballast.
The "other" Pink wire not going to the coil should be going to the Ign sw. cranking terminal, again,~.5V less than Batt.V with the key in crank position unplugged from ballast.
That "Pink" wire runs to the starter relay? Unplugged from the ballast it should only have B+ w/the ign. sw. in the cranking position.
Yes, the wire from Coil Neg. is going to spark, You're grounding the primary side of the coil......but Your supposed to be tapping that wire to ground, mimicking points &
watching for spark out of the coil wire.
Most modules won't operate below 9V, if the Batt. is that low with just the key on, it may be dropping out cranking for sure...........................
Forgot.....'84....could run in to ign.sw. or to starter relay..............what say the
diagram?
Click to expand...
 
Appreciate the input/help. I thought it might be nss but I tried starting in both park and neutral and same results lotsa cranking with no fire.
Terminals spotless, checked for continuity on grounds and were good (have continuity)
Thanks
Capt46 said:
Just my
Two cents worth did you check your neutral safety switch?
Click to expand...

Capt46 said:
One other thing I remember is the grounds from the battery.
Click to expand...

Capt46 said:
Had the symptoms years ago same situation I cleaned the terminals and then it started and ran perfect. Sounds to simple but just thinking out loud
Click to expand...
 
Thanks Dave, I cant recall, if I did test i didnt right down the results. I have added it to my list of tests to do tomorrow.
Another test I performed is coil -ve to ground with ecu unplugged is 1.5 V??
Another test is cavity 2 on ECU (unplugged) and ground i got 10V.
I also checked resistance on dist leads leading away from dist (hope that makes sense) and got 190 ohms which manual states is within spec and good.
Thanks again Dave I will perform coil +ve crank test tomorrow.
Daves69 said:
What voltage at + side of coil with ECU disconnected while cranking?
Click to expand...
 
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?
If my helper comes out and turns engine over while im under the hood, I can hear a "click" when they shut key off.

I admit the wiring isnt the greatest under there but its not "terrible" or totally butchered.
Its handy being able to use known working parts from cuda and/or using it for reference. One thing that is different is the starter relay. I can't simply swap to check.
Im unsure how to test it, any ideas?
Its a 7 blade and heres a pic.
Thanks TB, I will post test results tomorrow.
TrailBeast said:
Check you distributor connector Steve.
I have seen those contacts inside them spread open and not make contact.
If they don't make contact then nothing tells the box to fire the coil.
Since it fires when you turn the key off you know it has power available.
It sparks when you turn the key off and that is what the igntion box does, (shuts the ground to the coil off momentarily to make the coil fire) so that pretty much narrows it down.
Click to expand...

20170923_104713.jpg


20170923_104730.jpg


20170924_001251.jpg
 
4spdragtop said:
Ok ill try and answer/post results in order of how they were posted here.
Family dropped by so had to drop tools for the night.
Killer6, the battery voltage was approx 12 ish. Its a little low due to me constantly trying to start it with no success. So charger is on it now.
I will chk tomorrow for voltage drop of 0.5 V at red wire on ballast.
Other pink wire (non coil one) on ballast leads to 7 blade starter relay.
I didnt chk voltage but did chk for continuity and it shows continuity.
What do you mean "B+ while cranking"? Not sure what you mean sorry.
I understand the sparking from coil -ve when grounding but the wire that is supposed to spark (coil wire from center) is NOT sparking, no matter how close to ground I hold it. Strictly the one from coil -ve to battery -ve .
Not sure which wire you are asking about as per schematic?
Thanks for the help!
Click to expand...
OK, You need to check that pink wire at the ballast unplugged from the ballast for voltage when the key is in cranking position only, again it should be within .5V of what
the batt. is reading at that moment(usually mid 10's-mid 11's if the eng is cranking)
The coil wire spark test,......are You tapping the jumper to the Batt. Neg post quickly? And I assume You switched out the coil wire to eliminate that so...........You may
need as mentioned to keep the module unplugged while performing that test because they give a ground w/some resistance.
 
TrailBeast said:
Check you distributor connector Steve.
I have seen those contacts inside them spread open and not make contact.
If they don't make contact then nothing tells the box to fire the coil.
Since it fires when you turn the key off you know it has power available.
It sparks when you turn the key off and that is what the igntion box does, (shuts the ground to the coil off momentarily to make the coil fire) so that pretty much narrows it down.
Click to expand...
Right, only two things show this symptom, no dizzy pulse/power-down, & no voltage to coil cranking/turn-back to run position power-up as the engine stops turning.
Edit; Should clarify, !st scenario the key has to be turned back to "OFF"
2nd scenario the key just has to be let up from cranking back to "RUN"
 
Last edited:
Ok I forgot to mention I did a ballast swap (known good)from cuda to truck n vice versa. No change in truck and cuda starts runs with truck ballast. So definitely not a ballast problem.
I will chk pink wire tomorrow for voltage drop.
I tried both tapping the coil -ve wire quickly to battery -ve and holding it there. It sparks when quickly tapped. Nothing when held (obviously) BUT no spark from coil tower at all. FSM says that's the wire that should spark not the coil-ve??
Yep I changed coil wires as well. No difference.
Killer6 said:
OK, You need to check that pink wire at the ballast unplugged from the ballast for voltage when the key is in cranking position only, again it should be within .5V of what
the batt. is reading at that moment(usually mid 10's-mid 11's if the eng is cranking)
The coil wire spark test,......are You tapping the jumper to the Batt. Neg post quickly? And I assume You switched out the coil wire to eliminate that so...........You may
need as mentioned to keep the module unplugged while performing that test because they give a ground w/some resistance.
Click to expand...
 
4spdragtop said:
Ok I forgot to mention I did a ballast swap (known good)from cuda to truck n vice versa. No change in truck and cuda starts runs with truck ballast. So definitely not a ballast problem.
I will chk pink wire tomorrow for voltage drop.
I tried both tapping the coil -ve wire quickly to battery -ve and holding it there. It sparks when quickly tapped. Nothing when held (obviously) BUT no spark from coil tower at all. FSM says that's the wire that should spark not the coil-ve??
Yep I changed coil wires as well. No difference.
Click to expand...
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.
 
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