APillow

iTrader: (3)

Ok I know we have a bunch of MSD 6010 hating threads, but most are "no start" or completely dead out of the box issues. Then buried in these threads multi times you will see "my MSD misses and misfires", but no one addresses those points.

Let me start:
LM7 w LS2 camshaft and carb (new Demon 625) running a MSD 6010 box.
Runs fine and starts right up.
4 gauge ground between heads and 0 gauge to battery and frame rail. 0.0000 Ohms resistance from MSD ground to any of the other points listed. Clean 12v power of a relay (DPST? I cannot remember the acronym).

BUT it will randomly miss on the street. Cold/warm/hot engine conditions. Load doesn't matter. Part throttle, idling, full power... Doesn't make any difference.

Feels like the MSD is almost shutting off or "hicupping" for 1-5 seconds and then comes back perfectly to life! Perhaps the timing goes haywire for a moment? IDK No backfires though.

Brand new CKP sensor (Crankshaft), but did not change anything. The FI guys seem to have this issue as symptoms.

It is driving me CRAZY!!!

If it was a bad harness, I would think a bank of cylinders would have a consistent issue, but this is not the case.

Thanks for ANY insight. I have tried to cover and search everything before I brought this up so it didn't look like I'm crying wolf too early.

FWIW I'm putting 80+ miles on it today from work and back, so it runs. But not 100%.

Thanks!!!

APillow

iTrader: (3)

Last night I spent some time with the laptop plugged into the 6010... Even under the "sputtering" the MSD software reported normal real time conditions on timing, power (14.5v), and the rest of the tables.

But I did notice that the Demon 625 was very cold at its base. Letting off condensation "sweat" off the base of the carb. Cold to the touch. Even the Edelbrock intake manifold never really gets warm to distribute heat the carb... Most of my driving has been in the perfect "icing" range of ambient temps and humidity for icing...

Anyone had issues with "icing" on street driven LSX swaps?

This takes me back to the old air-cooled VW days where this was a problem. Choke itself out, wait a minute for the exhaust heat to warm the manifold and carry on

Z284thgen

iTrader: (46)

plugs very old maybe cracked fouled etc

do you have spare coils to swap all out and see if issue goes away

APillow

iTrader: (3)

Mother Trucker!!! This whole time there has been some internal issue with the MSD harness!!!

Accidentally I moved it around while testing coil pack spark and noticed an uptick in the idle... Then played some more! And found a sweet spot where all the planets were in alignment. Specifically the passenger side was giving fits and missing due to low spark.

I'm am now pulling about 18-19 inches of mercury steady as a rock on the vacuum gauge, before it was erratic and lower. (old school diagnostics)

Time for a new harness! Think MSD stands behind their products or no?

Probably not the best write-up / description here, but I'm relieved and pissed all at the same time.