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I installed an MSD atomic efi ,msd distributor , and ignition box that are all smog compliant on my 77 Corvette
The first smog check after install the smog tech asked me to change the fuel pressure regulator to non adjustable type. After that was done it passed with flying colors (in terms of emission numbers). The tech was still a bit unsure about the system because it is different and new to him.
The car certainly runs way better.
I left egr, efe, pcv, evap can and thermostatic air valve all connected. The various vacuum lines all went to either ported or non ported source on the atomic tb, following the same ported/ non ported connections as quadra jet.
The timing adjustment is fun to play with. On the little hand held you can adjust base, all in and "vacuum advance". At first I thought it was odd that they call it vacuum advance with no vacuum can on the distributor but it makes sense now having played with it. I will add a few pics soon.
The first smog check after install the smog tech asked me to change the fuel pressure regulator to non adjustable type.
Which regulator did you go with? Our 79 has a regulator that the smog tech mentioned wasn't technically allowed, but he passed it anyway. He retired last year, so I'm thinking for this spring's smog check, I might just replace it ahead of time.
Which regulator did you go with? Our 79 has a regulator that the smog tech mentioned wasn't technically allowed, but he passed it anyway. He retired last year, so I'm thinking for this spring's smog check, I might just replace it ahead of time.
I got this guy, I also changed fuel setting to pwm with regulator since this regulator does not allow for using the return line from atomic tb.
I got this guy, I also changed fuel setting to pwm with regulator since this regulator does not allow for using the return line from atomic tb.
Oops - I missed the 'efi' in your original post. My smog tech said my 4.5-9 psi adjustable regulator for my quadrajet wasn't technically allowed (he didn't mention if it was because it was adjustable, or because it just wasn't allowed period. I guess I'll just see what the tech says this year. Thanks!
adj pressure regulators, derek said it best
Does the atomic system have an EO# on it?
Getting so tough to pass 70-90s cars now
Yes it has an eo number. And so does the msd distributor , coil and ignition box I used. The distributor does not have a vacuum can and can be assembled with either functioning or locked centrifical advance. I set up the atomic to control timing so I locked the distributor centrifical advance and installed a special rotor.
the whole set up works well and brings the car up to early 90's tbi technology level. The biggest mystery to me was how would the atomic self adjusting system adapt to all the 70's exhaust valves and other smog components that switch on and off at certain temps. Having driven for a few weeks I can say everything works great.
Last edited by Greengear; Feb 26, 2020 at 10:55 AM.
Picture of msd atomic,
efe and associated tvs disconnect in pic , as I search for a vacuum leak post test. This has to be connected to pass visual test. It looks like the efe has a hole in the diaphragm. I guess this would only cause a vacuum leak during warm up. Anyways my 77 is running great compared to any other time in my ownership. I just recently swaped the auto trans for a 4spd and changed rear gear ratio to 411's. Still have a short list of things to fix
Last edited by Greengear; Feb 28, 2020 at 10:46 AM.
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Passed CA smog with msd atomic 77
