Need help with no spark

-
Ok here's what we have so far:

Battery voltage: 12.45 v
Input Ballast: 11.40
Output Ballast: 4.32

Coil +: 4.17
Coil -: 1.26

We get 11.85 to the blue wire going into the control box.

When we spin the distributor outside the car, we get 1.5 - 1.7 v A/C

We tried swapping another distributor, coil, and orange box and test for spark and nothing.

Two complete ignition systems and no spark from either...

The wires are all brand new going to the control box, coil, ballast, voltage regulator, and alternator with solder on all terminals. So our wires should be good...

We checked to make sure that the rotor points to #1 cylinder when the rib is at the reluctor...

We ran a ground wire from the control box directly to the battery negative, and also replaced the flat ground wire with a 10 gauge and made sure to scrape paint off the contact areas.

What else can we check???
 
Last edited:
4 V on Coil+ means a seven volt drop across the ballast resistor. You either have a very low resistance coil, high resistance ballast resistor or poor ignition box ground connection.

I get 7 V on Coil + and 1.7 on Coil -.

Did you measure voltage between battery negative and the different ground points? Ignition box in particular?
 
Looks like a few voltage drop issues. Bulkhead connections are biting you in the butt!
 
mguner said:
Looks like a few voltage drop issues. Bulkhead connections are biting you in the butt!
Click to expand...
Yes, the 11.4 on the ballast + side should be the same as battery voltage. You're loosing a Volt somewhere between the battery and the resistor.

I would disconnect the battery and measure the resistance in that circuit, form battery + pole shoe (disconnected) to ballast resistor + (with the ignition switch ON). Then from ballast - to coil +, coil - to ignition box (disconnected plug) and then ignition box ground back to battery - pole. It should read zero everywhere.
 
Good idea on the bulkhead connect check.
You might disconnect the electric choke if you haven't yet.
 
Hey we got spark!!!

After getting a phone call from another member here, it was suggested that the wiring harness for the electronic ignition may be the problem... (It's the only thing that we haven't swapped out for another yet...)

So I crimped some fittings on my other harness from a MP conversion kit, and we are getting a good strong spark out of the coil wire now...

Changed from orange box to chrome box and still have spark...

So we are going to start it and see if we can get through a full cam break in before I fit the MP harness to the existing wiring... Then I will pull the Jegg's harness out... (I want to be sure that it's reliable before we commit to it fully...)

As soon as Eddie gets back from his appointment, we will start it and see what happens....

A brand new electronic ignition harness from Jeggs seems to be the culprit.... :BangHead:
 
360DartGT66 said:
Yes, the 11.4 on the ballast + side should be the same as battery voltage. You're loosing a Volt somewhere between the battery and the resistor.

I would disconnect the battery and measure the resistance in that circuit, form battery + pole shoe (disconnected) to ballast resistor + (with the ignition switch ON). Then from ballast - to coil +, coil - to ignition box (disconnected plug) and then ignition box ground back to battery - pole. It should read zero everywhere.
Click to expand...


With the new ignition box harness, we are now at .7 voltage drop from 1.05...
 
Well, there ya go. Sounds like it was in the trigger wire connections from the distributor, since everything else checks out OK.Those issues are the hardest to find. Congrats!

BTW, to add to the notes on the voltage drops Karl reported....you had 7 volts across the ballast and 3 across the coil. With a typical MSD Blaster 2 coil primary resistance of 0.7 to 0.9 ohms (spec is 0.7 ohm but there are connection resistances), then those drops work out OK for an OEM type ballast, which is around 2 ohm hot after 30 seconds or more of heating. The resistances given in the chart in post #24 are COLD ballast resistances.
 
krazykuda said:
With the new ignition box harness, we are now at .7 voltage drop from 1.05...
Click to expand...
Because the ignition system is now pulsing the current rather than drawing continuous current, so the average current and voltage drops are now lower. Makes good sense....
 
nm9stheham said:
Well, there ya go. Sounds like it was in the trigger wire connections from the distributor, since everything else checks out OK.Those issues are the hardest to find. Congrats!

BTW, to add to the notes on the voltage drops Karl reported....you had 7 volts across the ballast and 3 across the coil. With a typical MSD Blaster 2 coil primary resistance of 0.7 to 0.9 ohms (spec is 0.7 ohm but there are connection resistances), then those drops work out OK for an OEM type ballast, which is around 2 ohm hot after 30 seconds or more of heating. The resistances given in the chart in post #24 are COLD ballast resistances.
Click to expand...

We have 4 ballast resistors. Three of them are at 1.3 ohms, and the other measures 0.8 - 0.9 ohms.

Now he wants to trade me the red Blaster 2 for my chrome Accel coil. I'm open to the trade...

Should I get the 0.8 - .09 ohm resistor to run with the MSD blaster and give him a 1.3 ohm for it??? Or will he be better with the 0.8 - 0.9 ohm resistor with the chrome Accel coil??
 
krazykuda said:
We have 4 ballast resistors. Three of them are at 1.3 ohms, and the other measures 0.8 - 0.9 ohms.

Now he wants to trade me the red Blaster 2 for my chrome Accel coil. I'm open to the trade...

Should I get the 0.8 - .09 ohm resistor to run with the MSD blaster and give him a 1.3 ohm for it??? Or will he be better with the 0.8 - 0.9 ohm resistor with the chrome Accel coil??
Click to expand...
Sounds like you have 3 like the MSD ballasts and 1 like the BWD19. I personally would not be running the MSD Blaster 2 on long road trips unless I had spare ballast and coil and ignition box to carry. The coil resistance + ballast is a mite low and will be heating things up; OK for the drag strip (like the 0.25 ohm 'performance' ballasts!).

What is the plan with your 2 cars? Strip only or street? And which Accel coil model? I personally would stick with a 1.5 ohm-ish coil for long road trips; just a lower heat, reliability preference for me. ANd if I was not original or stock oriented in the car, then I'd fer sure go HEI.
 
Well, it works still...

It was that dam harness...

The car starts right up now, and will be on its way to the exhaust shop tomorrow to get the headers tied into the existing pipes...

Thanks to all that helped and replied to our post. Hopefully this will help more people in the future that may run into this problem...
 
You must log in or register to reply here.
-

Back
Top