No spark

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twodog45

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I have a 318 out of a 71 d100 in my 64 cuda. Currently I am not getting any spark.
Items replaced: coil, ballast resistor, cap and rotor, plug wires.
I am wiring it to just get engine running. I have it wired thru the ecu, ballast resistor. I have power to the coil. Still no spark. How do I check the reluctor wheel and pick up coil? There is about .006 gap between them.
 
Is it running a stock type Mopar electronic ignition, or something else - HEI, MSD, etc?
 
Mymopar.com

Download your cars Factory service manual.

The year of the engine is much less important, the year of the wiring and ignition system is more important.
 
I copied this from the thread I gave you on Post#2.
Try disconnecting the dist. pickup. With the key in "run" and a test spark gap rigged to the coil tower, tap the exposed terminal of the engine bay side of the pickup connector to ground. One fat blue spark should happen each time

Measure coil V with key in "run." Coil + should be say, 6--10v (it varies) but not same as battery. NEG side of coil should be quite low, 1 or 2 volts. Quite high indicates coil is not conducting. Box must be grounded

Try jumpering 12V temporarily direct to coil +

Ballast resistor must be good. (Continuity)

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Put a test light on the neg side of coil.and crank it over you should see a blinking light if no blinking light problem is in the pick up or ecu make sure the ecu is grounded to body ,remove it and sand bolt holes to get a good ground , if you have a blinking light the problem is the coil the coil may have overheated while you were working on it ,do you have a coil for electronic ign.on it?
 
twodog45 said:
Regular canister coil
Click to expand...
You can't tell by looking at them ,if you ordered one for 74 and up you should be ok a point coil will have lower voltage and a different resistance thru it points 25000 / electronic about 45000 volt
 
teringer said:
You can't tell by looking at them ,if you ordered one for 74 and up you should be ok a point coil will have lower voltage and a different resistance thru it points 25000 / electronic about 45000 volt
Click to expand...
Yeh but it will still work
 
Check the p/up resistance with an ohmmeter. Disconnect the 2 pin plug at the dist. Resistance should be 150-600 ohms.
 
What have you done so far --what have you checked and what are the results? It is no good for us to come here posting this and that if we don't know what if any progress
 
MadScientistMat said:
I've been putting together a troubleshooting guide specifically for this.

How Chrysler electronic ignitions work, and what to check if they don'

I see you have power at the coil positive terminal, that's a start. Can you run through the remaining voltage checks and let me know what you find?
Click to expand...
This is pretty good, but a couple of suggestions

It might be helpful to explain that in when the key is in "start," the run circuit (IGN1) goes dead, and that the only ignition system source is the coil bypass circuit, normally brown, (IGN2).

It might help to explain than with the key in run, you expect LESS than full battery voltage at the coil, because the coil should be drawing current through the ballast, and dropping the full battery voltage. But in "start" the coil + should show whatever the cranking voltage is, and should be at least 10V or more

Maybe I missed it but another helpful test is the pickup "tap" test, where, with key in "run," you separate the pickup connector, and tap the bare terminal of the harness end to ground. This should generate a spark each time. If so, you may have distributor pickup problems, OR the connector itself can be faulty.
 
Its the module...I say this cause the last time I actually followed the "troubleshooting" procedure everything checked out good. I took a chance bought a Mopar module and toss it on and it fired right up...
 
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67Dart273 said:
This is pretty good, but a couple of suggestions

It might be helpful to explain that in when the key is in "start," the run circuit (IGN1) goes dead, and that the only ignition system source is the coil bypass circuit, normally brown, (IGN2).

It might help to explain than with the key in run, you expect LESS than full battery voltage at the coil, because the coil should be drawing current through the ballast, and dropping the full battery voltage. But in "start" the coil + should show whatever the cranking voltage is, and should be at least 10V or more

Maybe I missed it but another helpful test is the pickup "tap" test, where, with key in "run," you separate the pickup connector, and tap the bare terminal of the harness end to ground. This should generate a spark each time. If so, you may have distributor pickup problems, OR the connector itself can be faulty.
Click to expand...
Thanks, I'll give the article a few updates. I couldn't recall if the distributor triggered on the rising or falling edge of the signal coming in.
 
believe this is appropriate for both mopar and HEI.
on the approach the reluctor peak causes the voltage to swing low and the low dip gets bigger the closer the reluctor vane gets to the pickup centre
when aligned though, its at zero because the voltage has to change direction when the reluctor vane swaps from approaching to leaving the pick up
as it moves away the voltage swings high
at the correct + voltage trigger level a spark is created, and as you can see with a fast rpm you get a bigger voltage peak than with a low rpm small peak, for both cases the trigger point varies by only a tiny amount, a very slight retard built in, that is linked to RPM

swap the trigger coil wires round, (impossible with an offset mail/female mopar plug, you'd have to cut it off) and you start triggering off the dip in voltage.
and the start of that curve and the bits that hit the trigger point on the negative side are miles away from each other, a truly unacceptable variance in timing vs rpm caused by the trigger coil being connected into circuit backwards.
always trigger after the voltage swings+ and crosses the 0 value on the y axis (voltage) doesn't matter where that is on X axis (time) because time is linked to RPM and you SET your timing.

this is totally dependent on the shape of the swoop down, abrupt up (trigger on this), swoop back down signal created by the reluctor approaching and leaving the magnetic field centred in the middle of the pickup.

if it helps turn the image upside down to indicate backwards wiring of pickup

a backward trigger.JPG
 
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