What would cause a weak spark?

[garyo]

My spark is orange and from what I gather it should be blue or white. Its a 1970 Dodge d100 with a 360. I converted it to electronic ignition and have a msd blaster coil.

[Hobcobble]

My spark is orange and from what I gather it should be blue or white. Its a 1970 Dodge d100 with a 360. I converted it to electronic ignition and have a msd blaster coil.

Garyo,
Which EI system did you install?
John

[garyo]

Its what came with the crate engine, the factory mopar electronic ignition with the orange box.

[Hobcobble]

Did you check the gap for the distributor magnetic pickup?
[brass gauge]
John

[garyo]

Yep, I checked it. After readjusting still orange. I wonder should I be use the stock coil and stock resistor?

[Trailmaster]

I'd try the stock parts just to see what happens.

[Jeffc]

If your using a ballast --- non resitor coil only.....
poor ground is most common problem if the rest of the system is up to snuff....
If your cables from neg side of battery have not got good contact or are old
replace them, be sure that were you mount the EI box and coil has good ground!!

[garyo]

Someone told in the crank position I would have a weak spark. I need to run a wire from the crank side of the relay to the + wire going to the coil.

[Jeffc]

When in the start mode (key to start) you want full voltage to the coil to give a stronger
spark (why with a ballast- the ballast is by-passed in the start mode).....
After start (key in run) the ballast will reduce voltage to the to the coil to keep
it from over heating......
Coils with a built in resitor reduce useable voltage and if used with a ballast will
reduce it even more, so if you have a coil with built in resitor removal of the ballast
from the system is needed..... or install a non-resistor coil (stock type)

Ether way your spark should still be white to blue in color, yellow color is very weak spark