I have a 383 Stroker in my Camaro and an MSD distributor that looks to be a ready-to-run billet (Model# is facing the firewall and looks like 8360 or 8380). The coil is a Blaster 2 model 8202. I’m including a picture below as a reference.

It’s been running fine for more than a year and I’m suddenly having spark issues this week. With key in run position, I have power on both sides of the coil. When trying to start, I have flashing on the test light when connected to the negative coil terminal. When grounding the coil wire from coil to the block or firewall and trying to start it, I’m not getting a spark.

I’m testing the coil with a multimeter, with all connections removed from the coil. I’m reading .7 ohms between the terminals and 4k – 4.2k from the tower to either terminal (which look to be in spec based on MSD doc).

Is this enough info to say what’s wrong or what to replace?
Thanks in advance,

 

Swap in another coil, any coild and compare results.
Dist is doing its thing by pulsing the coil on the negative terminal.
Coil is not making any spark, no field being generated.
You also might jumper in battery voltage to the coil pos terminal just to be sure the coil is getting full battery power.
If you use the OE cloth covered wire, the reduced voltage from running may have diminished the power available to generate the spark.

In looking at the picture, and you have a TH350 trans, the vacuum line from the nipple, ported vacuum, next to the fuel bowl sight screw, runs down and to the rear of the engine. If this vacuum line is going to the vacuum modulator, this vacuum source may be contributing factor to incorrrect upshifting of the trans at any throttle position other than WOT, wide open throttle. No/low vacuum, late upshift.

 

You never did go into detail about what "I’m suddenly having spark issues" means. Is the engine killing on you, sputtering, losing power, just plain old not starting, or what?
I agree, swap another coil from something else to test it. I've had a couple coils go bad in the past, and both acted fine until the engine (and coil) heated up, then it would crap out.
In addition to your vac modulator wanting to be hooked up to full manifold vacuum (it appears not to be now), your distributor wants to be hooked up to ported vacuum, which it isn't. Swap those two hoses on the carb. Or perhaps the vacuum advance mechanism has been modified from how it came out of the box so that it can operate properly on manifold vacuum? That's not causing your no-spark issue though.

 

That's funny, I was thinking the same thing that 69 Camaro said about the vacuum line going to the distributor.

Here is something else to think about. Is your wiring harness the factory harness? I've seen people install a MSD or HEI distributor and because this draws more power, a lot of times it will burn up the factory resistor wire that goes between the firewall plug and the distributor.

All you really need to do is replace this wire with a heavier gauge wire, like 10awg.

Just something to think about.

Looks like a clean engine bay, nice job.

 

Thanks to all for the replies- here's some follow up info:

Camaro 69: The spark issue is it won't start at all (pretty important part I left out! ).

Thanks for calling out the vacuum issues- I now have a new project to tackle once the spark issue is resolved!

Bruce: Thanks for the kind words on the engine bay- it's tough keeping it looking like this!

I played with it some more tonight, swapping out the coil with a new direct replacement Blaster 2 and got the same results. I also tested voltage on the positive terminal when cranking and I'm only getting 5 volts or so. Sounds like I'm somehow not getting enough juice to the coil? I have a light pink wire going to the pos terminal that seems to go to the firewall. Then I have a single loom with an orange and red wire- red is on positive and orange is on negative. I assume this is the MSD loom that came with the ignition kit. The pink wire from main harness is also on the positive side and I assume this is the factory resistor wire? Everett and Bruce mentioned running 10awg wire straight from 12 volts... is that only for a test or is that a safe permanent solution to replace the pink wire?

One other thing I noticed tonight that also happened before is, after cranking for a good 5-10 seconds and letting off the key, the engine sounds like it exhales a quick breath. Then, if I turn the key off, the engine and fan turns a fraction of an RPM. not sure if this is a sign of something?

Not quite sure what to test next- because it's a ready-to-run distributor, I don't believe there's an MSD box anywhere? Any other ideas what to try next?

 

It sounds like your wiring is correct, the MSD harness should have three wires, orange, red and black. Black is ground, red is + and orange is -.

Since you are saying you only have 5v's at the + of the coil, I'd follow first that pink wire back to the firewall and check what kind of voltage you have at the firewall. If you got 12v there, then that lead wire might be bad. This is the wire that I was talking about, from factory, is a resistor wire and can burn up. You can replace this wire with a heavier gauge wire to prevent this.

If for some reason you don't have 12v at the firewall, you may need to go inside and check to see where you lose the power at.

It could be a bad spot on your ignition switch. Luckily on you car, they are easy to replace.

Do you have a wiring diagram for your car. They are a big help.

I'm showing my age now, because I forget, is there a fuse for the ignition?

I'm pretty sure your distributor is 8360 and you are correct, you should not need a box, these are ready to run.

 

Thanks for the replies- I'm thinking I have all the info to head back out to the garage.... Just a few replies/ questions:
1) I do have an ignition fuse and verified it's good.
2) do you know where the ignition switch is? I found lots of pics online of the switch however, not the location of it.
3) if I have 12 volts at the ignition switch then I assume it's the burnt resistor wire you suspected. Do I simply replace this with Plain wire but heavier? Is there any special "resistor" wire?
4) do I run this replacement wire between the same contacts between ignition switch and coil or, do I need to run 12v direct from fuse box?

 

The ignition switch is behind the dash where you insert the key.
To remove switch insert a paper clip into the hole of the tumbler and push hard and at the same time, unscrew the tumbler out of the body.
Now unscrew the bezel and switch will fall into the dash.
Unplug the connector from the body and you have the switch in your hand.
New electrical portions can be bought for replacements.
Sixty-eight's do have ign voltage in the START position.
It may have burnt contacts inside the contact area.
I have un-swaged the switch and tore it apart, do this feat in a cake pan for collecting the parts coming out, and emery paper the contacts, then reassemble and reswage.
START ign voltage comes back.
The resistor wire is from the engine side firewall connector to the coil.
The wire is nichrome, ie, nickel in the recipe.
Most have cut the wire up to within two inches of the firewall connector and soldered a plain wire to the short pigtail. Many do this for HEI installs.
However, there is an IGN spade on the fuse panel and one can install the new ign supply wire to the spade.
You can run a temporary jumper from the battery positive post to the coil pos terminal just to see if the engine will fire. If engine does start, you will know the ign does not get ign voltage at the START position, hence the OE yellow wire from the solenoid R terminal to the coil pos terminal.
I would charge battery first, if using a late model charger, leave the charger in 2A position over night as this will be a 'deeper' charge.
Now you will get full battery voltage to the dist/coil.
The new RTR dist probably needs full battery voltage to operate at its best as the mfr's imstruction does not say to use the resistive wire, but use ignition voltage.

 

And there you have it, Everett pretty much summed it up.

I said earlier that you could replace the resistor wire with a 10awg wire, after I thought about that, that wire is a little too large and you probably could get away using 16 or 12awg wire.

Keep us posted on what you find out.

Good luck

 

Yes, you did, Bruce, and I did not mean to take away from your suggestion.
But, how many times in the ign sw life has the sw been in/out of START?
More than we can count on two hands to the eighth or ninth power...

I did add two marine pushbuttons, engine compartment for adjusting valves, and dash where the radio ON/OFF **** would go, just in case ign sw did not work.
Then I cleaned the sw and 'it's back'.

In splicing a copper wire to the nichrome wire, solder does not take to nickel, but brazing does take to nickel, but then, if you're not paying attention, the copper melts way before the nichrome wire. So, some people use the IGN spade on the fuse panel.