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Author Topic: No Power to Coil While Cranking / No Spark  (Read 1925 times)

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Offline fatpretzle

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No Power to Coil While Cranking / No Spark
« on: July 5, 2009, 04:42:44 PM »
Ok guys. I need your help again. I have a 1977 B200 van with a brand new motor in it. We are trying to start it for the first time but it seems that we have to power to the coil while we are cranking on it. We replaced the ignition module and ignition switch with one out of the parts van and that didn't help. It will actually try to start if we let go of the key sometimes after cranking for a bit. Anybody have any thoughts?
Thanks
« Last Edit: July 5, 2009, 06:12:37 PM by fatpretzle »
93 Dodge Ram 3/4 318 Magnum 2wd Dana 60 LSD
89 Ramcharger 5.9L TBI D44, 9.25 LSD

Offline ToxicDoc

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Re: No Power to Coil While Cranking
« Reply #1 on: July 5, 2009, 04:53:34 PM »
are you getting spark?  Test the coil resistance too.  Also, make SURE you have power to the coil + in both "run" (9volts) and "start" (12 volts) position.
'85 W150 SB, 408 stroker, Magnum manifolds, Performer RPM, 670 Truck Avenger, HEI ignition, Auburn LSD 9.25 and '82 D44 (non-CAD) with 3.55/3.54,  NV4500/NP241

Offline s ǝoɾ

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Re: No Power to Coil While Cranking
« Reply #2 on: July 5, 2009, 05:15:27 PM »
are you getting spark?  Test the coil resistance too.  Also, make SURE you have power to the coil + in both "run" (9volts) and "start" (12 volts) position.
Doc, he said one key phrase "will try to start when we let go of the key"

I must presume this van has dual pickups and a start/run solenoid?
Avoid replacing any part that you have not proven to be faulty through extensive testing.

Offline fatpretzle

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Re: No Power to Coil While Cranking
« Reply #3 on: July 5, 2009, 05:52:09 PM »
I'm not sure if it is a dual pickup but it definitely has a starter solenoid. We tried to run a constant 12v to the coil and that didn't work. Then we realized that it was on a switched ground so we ran a constant ground to it and that didn't work. I believe that we had power to the coil in that scenario but we still had no spark.
93 Dodge Ram 3/4 318 Magnum 2wd Dana 60 LSD
89 Ramcharger 5.9L TBI D44, 9.25 LSD

Offline fatpretzle

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Re: No Power to Coil While Cranking
« Reply #4 on: July 5, 2009, 06:05:10 PM »
O and we also had a problem with the neutral safety switch. It would only crank if it was in neutral not park. Don't know if its related though...
93 Dodge Ram 3/4 318 Magnum 2wd Dana 60 LSD
89 Ramcharger 5.9L TBI D44, 9.25 LSD

Offline ToxicDoc

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Re: No Power to Coil While Cranking
« Reply #5 on: July 5, 2009, 06:27:01 PM »
Doc, he said one key phrase "will try to start when we let go of the key"

I must presume this van has dual pickups and a start/run solenoid?

I caught it to, but I keep forgetting about that dual pickup that Mopar used.
'85 W150 SB, 408 stroker, Magnum manifolds, Performer RPM, 670 Truck Avenger, HEI ignition, Auburn LSD 9.25 and '82 D44 (non-CAD) with 3.55/3.54,  NV4500/NP241

Online SuperBurban

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Re: No Power to Coil While Cranking
« Reply #6 on: July 5, 2009, 06:34:54 PM »
Doc, he said one key phrase "will try to start when we let go of the key"

I must presume this van has dual pickups and a start/run solenoid?
I caught it to, but I keep forgetting about that dual pickup that Mopar used.

I agree, thats what it sounds like, but I did not think they used the dual pickup until the mid 80's.  I've never seen it in a 70's truck.
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Offline ToxicDoc

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Re: No Power to Coil While Cranking
« Reply #7 on: July 5, 2009, 06:50:38 PM »
O and we also had a problem with the neutral safety switch. It would only crank if it was in neutral not park. Don't know if its related though...

Neutral safety switches, clutch switches, etc cut out the starter circuit, not the ignition.  You should still get spark.

Double check for proper current to the coil, check coil resistance, check for actual spark.
'85 W150 SB, 408 stroker, Magnum manifolds, Performer RPM, 670 Truck Avenger, HEI ignition, Auburn LSD 9.25 and '82 D44 (non-CAD) with 3.55/3.54,  NV4500/NP241

Offline fatpretzle

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Re: No Power to Coil While Cranking / No Spark
« Reply #8 on: July 5, 2009, 08:47:55 PM »
Ok. What should I get for an ohm reading on the coil? My multimeter doesn't read current but I know that the coil is only getting about 2v during cranking and there is no spark from any of the wires until I stop cranking. Once I stop cranking it will spark once.
93 Dodge Ram 3/4 318 Magnum 2wd Dana 60 LSD
89 Ramcharger 5.9L TBI D44, 9.25 LSD

Offline ToxicDoc

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Re: No Power to Coil While Cranking / No Spark
« Reply #9 on: July 5, 2009, 09:06:43 PM »
Primary resistance should be about 1 ohm or less.  Secondary should be under 10K for certain, some sources say under 5K.

http://autorepair.about.com/od/troubleshooting/ss/coil-test-ohm.htm


However, if you are only getting 2 volts (you measured it right?), then you have identified your problem.  You need 12 volts.  Trace that circuit wire.  You have too much resistance in it.  All contact connections need looking at and the wiring for fraying.

'85 W150 SB, 408 stroker, Magnum manifolds, Performer RPM, 670 Truck Avenger, HEI ignition, Auburn LSD 9.25 and '82 D44 (non-CAD) with 3.55/3.54,  NV4500/NP241

Offline fatpretzle

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Re: No Power to Coil While Cranking / No Spark
« Reply #10 on: July 9, 2009, 08:05:46 PM »
Ok. We have tested and checked this thing any way I can think of. We have replaced the balast resistor and ignition module. We even ran a hot wire straight to the coil. Nada. We still have about 9v at run but once we start cranking it just drops to 0V.  We are lost. It worked fine before we took the motor out and rebuilt it. Does the ignition switch control the power to the coil wile cranking?
93 Dodge Ram 3/4 318 Magnum 2wd Dana 60 LSD
89 Ramcharger 5.9L TBI D44, 9.25 LSD

Offline s ǝoɾ

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Re: No Power to Coil While Cranking / No Spark
« Reply #11 on: July 9, 2009, 08:40:21 PM »
how many wires go into the base of your distributor?

How many wires go into the module? 4? 5?
Avoid replacing any part that you have not proven to be faulty through extensive testing.

Offline fatpretzle

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Re: No Power to Coil While Cranking / No Spark
« Reply #12 on: July 9, 2009, 08:47:10 PM »
2 wires to the distributor and 5 wires to the module.
93 Dodge Ram 3/4 318 Magnum 2wd Dana 60 LSD
89 Ramcharger 5.9L TBI D44, 9.25 LSD

Offline s ǝoɾ

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Re: No Power to Coil While Cranking / No Spark
« Reply #13 on: July 9, 2009, 08:58:16 PM »
Where did you place test leads when measuring voltage at the coil? Which lead went on what part of what component?
Avoid replacing any part that you have not proven to be faulty through extensive testing.

Offline fatpretzle

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Re: No Power to Coil While Cranking / No Spark
« Reply #14 on: July 9, 2009, 09:02:28 PM »
I tested it many times in a bazillion different ways. I tested it with the leads on the positive and negative side of the coil. I tested it with the coil disconnected with the leads connected to the pos and neg wires that were disconnected from coil. I tested the pos wire on coil and neg wire on block and neg wire on coil and pos wire on battery. I tested the voltage being sent to the coil from the balast resistor and I checked the voltage at the negative lead on the voltage regulator and the battery.
93 Dodge Ram 3/4 318 Magnum 2wd Dana 60 LSD
89 Ramcharger 5.9L TBI D44, 9.25 LSD

Offline moparmike72

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Re: No Power to Coil While Cranking / No Spark
« Reply #15 on: July 12, 2009, 01:30:20 PM »
I fought that dual pickup setup on my '86 R/C for quite a while, then finally switched to a Wells 4-pin GM distributor module:http://duster318.freeservers.com/tech/hei.html
Wired it to the "run" pickup, tossed the ballast resistor and mounted an Accel 1 1/2 ohm coil on the fenderwell. A Ford TFI coil or a late model Mopar spool-type coil would work well also. Lotsa sparks, starts right now and doen't seem to be near as fussy about the choke adjustment as it used to be. Now I carry a spare ignition module in the glove box(where we normally carry spare ballast resistors) but it doesen't look like I'll ever need it.
My company car is a Kenworth

'86 Ramcharger. 5.9 auto
'96 Ram 2500. 8.0 auto

Offline ToxicDoc

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Re: No Power to Coil While Cranking / No Spark
« Reply #16 on: July 18, 2009, 09:29:09 PM »
Updates?
'85 W150 SB, 408 stroker, Magnum manifolds, Performer RPM, 670 Truck Avenger, HEI ignition, Auburn LSD 9.25 and '82 D44 (non-CAD) with 3.55/3.54,  NV4500/NP241