Stock block and head b16, 50trim, Msd6al, 440dsm, tuned on s300v3, running extremely rich... Afr 9.8 at idle. Compression tests show 180 average (179-181) fuel pressure 44psi at regulator, new injectors measure in spec for resistance, no CEL, powerful spark across all cylinders.

​​​​​I'm fouling plugs immediately, getting tons of black smoke from the exhaust, and when I check the plugs, smoke, not steam comes from each cylinder. I'm not having any issues with coolant of oil mixing, although my oil smells rich of fuel. These all seem symptomatic of a bad FPR, so I switched to another known working unit, for no change in symptoms.

​​​This entire swap, including the whole cars wiring system, was swapped over from a rusty bucket shell, into a much better body...EVERYTHING was moved from a running and driving car, without these issues (fuel tank, wiring harnesses, dash, blah, blah). Only changes were the new direct replacement of the dsm440s and fpr (knockoff), and the addition of the msd coil system (car won't even fire with known working stock distributor???​​​Edit- Removed msd set up in favor of stock dizzy, used incorrect rotor, runs but same issues.)

​​​​Car fires up immediately, stumbles fairly heavily thru rpms, and smokes like snoop. Hoping to gain access to a leak down tester shortly, any advice guys?
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AFR 9.8:1 at idle is why. Time to get it retuned.

 

Thats not a symptom, that's an outcome. I'm searching for what the cause of that is.... Im green with all this, how does a tune simply jusy go bad?

 

Retune it. The problem (or what may actually be a solution that you didn't know about) is in the new injector seemingly. You can also reinstall your old injectors; if everything reverts back to being "normal" then it definitely lies in the new injector/tune mix.

 

I should have been more clear, sorry. I thought the injectors were the issue, that's why I replaced them with the exact same reconditioned units... No change. Reverting back to old injectors showed no changes. How would tune be effected?

 

Your fuel pressure regulator could have an issue.

 

Definitely possible, they are both cheap units, I haven't had luck with any changes after swapping old for new, new to old.... Im just figuring there is something else going on, rather then two components failing... Are these symptoms suggestive of either valve seals or rings, more prodominatley? Any other test useful besides leakdown?