Ok, I checked the spark on my 83 gsl becuase the car started to back fire now & again & would hit flat spots in the higher rpms.

I checked it use a little tool I use for my offroad toys.
It's not strong. Orange in color, on both the leading & trailing.

I've replaced: plugs,plug wires,cap & rotor, coils and ignitors.

Any ideas what I should do next?

 

the color of the spark isnt always a good way to judge its strengh, if you really wanna see if your spark is strong hold the leading wire close to your strut mount bolt or something thats a good ground while someone else is cranking the engine, the spark should be able to jump almost half an inch or more if its strong, if it wont jump past a 1/4 or an 1/8th of an inch then you have a problem, if the spark is weak check the source voltage going to the coils, if thats low the coil charge will be equally low

 

ok I'll check them both.

I aways thought a blue spark is best. Funny that evey other engine good running engine I have all have blue spark.

anything else I should look into?

 

oh, what should I see at the + leads on the coils? 12 volts?

 

I've seen full alternator voltage (14.0 or so) at my coils. Of course I've done a few things.

 

yeah the only thing I done to it's charging sytem is put on a S5 80 amp alt. Left over from when I installed a new FD alt. on the 10th ann.

Though I still don't think I would ever want to see 14 volts on the laptop. Indication of faulty voltage regulator or alt.

anyone have any other ideas about the spark?
Could it be the pick-ups or condenser?

 

I have really bright headlights too. It's a faulty alt wire in my REPU (the battery is all the way under the bed and has a lengthy wire which is old).

Your voltage is supposed to be 13.8. Right? Just measure the alt output, then the battery + terminal, then the + on each coil. If there is a large difference, it means your key switch wires (or the switch itself) are tired.

 

I put a leading plug wire about a 1/2" away from diff. grounding points on the car like you said. It wouldn't jump. If I got closer to ground, about a 1/4 " away, it would jump, but it would miss every so offten.

Checked the power at the coils, both had about 12.5 volts.

So, now what?

 

Just to up date/end the thread:

I found the problem. It was the coils. They were MSD Blaster 2's. For whatever reason, they coundn't get the job done. I have no clue why.

I put in some FC trailing coils, just to make sure it wasn't the MDS coils. BAM!!! Stong, blue spark!!

Guess it just backs up what we already know about how good the FC coils are.

 

And how crappy the MSD coils are? Thanks for the follow-up to this thread. It's cool when stuff works out.