Clicking Sound in Engine Bay
 

Quick update: After having the '80 finally pass smog, I still haven't registered it yet which brings us to it being up on blocks. I've now fixed the temp gauge, heater fan, rebuilt the diff (pinion was shredded), new wheel bearings, new wheel cylinders, etc... Trying to find a M10 x 1.25 brake line which is being elusive (original one was frozen in the old wheel cylinders).

The problem:
Every couple days I start it up to make sure nothing has gummed up and such but these last couple times, a ticking noise starts once the car is somewhat warm. I have so far traced it to the rats nest solenoid rack. Somehow it is related to the AVC control solenoid (blue). My whole set up is a bit of a mash up (late model 12A with all smog stuff but an SA ECU), so I've got stuff wired backwards and sideways etc... but it always runs fine. When I remove the solenoid the clicking stops, however, I have to jump the vacuum line over so that the idle doesn't suffer as below 1000ish rpm, the solenoid is open. The sound only occurs when the solenoid is present, but doesn't if I do the equivalent job with a vacuum line. I've swapped solenoids and they all do the same thing. The sounds is a little on and off, but it will always happen after you rev and it returns to idle. Solid 12V to the solenoid and it doesn't click if it's not in the vacuum loop.

Thoughts?

If you are running an SA ecu then I would suggest running an SA rats nest. The later emissions rack has more solenoids and a much different vacuum plumbing. These cars don't do so well with makeshift and or mix matched parts. You have to get a known good baseline before proper diagnostics can be performed.

Before the swap I figured out that the only things that wouldn't hook up correctly were the split air and shutter soldenoids, and as of now both are not a required feature to run properly. The early TPS (or equivalent) was a simple on off switch, while the latter ones used a variable resistor. Due to this I installed the early TPS on the later carb, plugged or hooked up the appropriate uncontrollable vacuum lines so that they would be in the proper op conditions, etc. My car has a the later, intake, ACV, carb, etc.. so the only issues are controlling the extra (and in this case unnecessary) components. When I took apart the ACV, the control valve diaphragm (perhaps called the relief valve although I don't remember) was extremely dry rotted, which I attempted to fix with some silicone after cleaning. Now it does operate, but it's travel is limited so it can't close entirely. Everything is, or at least was functional and I had gone through every part before mixing and matching.

At this point I know the system "worked" and as of now it's still operational. I'm really only curious if the sound is indicating some sort of issue or similar.

Thanks for your help thus far.

Well I confirmed a couple things this morning. 1, this happens with any solenoid that I power with the blue relief plug. 2, it only happens if vacuum is running "backwards" through the solenoid. I'm going to guess that it's not getting the proper amount of juice onces it's warmed up or something since it happens to all solenoids. It's 12V with nothing connected, but maybe it's inconsistent or something. I say backwards only because all but the AC solenoid would normally run the other way. Due to the combination of the two systems, I had to invert the solenoid because it gets sent power opposite of what the later models did.