Merak SS Floods Easily and Runs Too Rich At Idle

Since resurrecting my 81 Merak SS from five year storage, I've pulled gas tanks and had them professionally boiled out, changed oil and filter, installed new NGK BP6ES spark plugs, measured resistance of plug wires, removed and cleaned needle and seats and idle (size 70), main (size 200) and pump jets in each of the three 44 DCNF carburetors. Also installed new fuel filter. Examined and cleaned distributor cap and rotor. Also measured cylinder compression readings (150 to 160psi across all cylinders with engine cold). Only 15k miles on the engine. And all six fuel mixture screws are set to about 1 3/4 turns out.

Since the above work, it's been a challenge to start the engine. It seems to flood easily and is definitely running too rich at idle speed. Today I was able to start it and run it long enough to measure vacuum flow across all three carburetors. They are all pretty even. But the engine won't maintain idle speed and feels as if it's running too rich at idle. It clears up a bit when I rev the engine to 2500 to 3000 rpm range, but when returning to idle speed it doesn't hold and eventually engine will die. While engine was idling I noticed that the exhaust from the left tail pipe was steadily pulsating pattern (POP..POP..POP), while the exhaust from the right tail pipe was just a steady flow. What could be causing the POP POP POP from the left side exhaust pipe?

I haven't checked engine timing yet. What should the static timing be? Assuming timing is fine, not sure of next steps to take to get the car to start easier and hold the idle. Pulling each carburetor and performing a more thorough cleaning of the entire carburetor bodies and replace gaskets and pump diaphragms seems like a good idea. Any other recommendations?

Thanks,
Steve

 

Thanks Julian. I'll check fuel pressure, but I think it's fine.

I'm wondering if I have a failing Bosch CDI box or a weak ignition coil? My car is a late US spec SS so it has a single coil. I think to test the ignition coil I just measure the resistance of the primary and secondary windings. Primary winding resistance should be around 0.4 to 0.6 ohms and secondary resistance around 650 to 790 ohms?

But not sure how to test the Bosch CDI box. Mine is a gold color. I think I should measure 12V at one of the terminals at the connector. The terminal that leads to the battery. But not sure what else to measure on it. Is it supposed to make a whistle sound with the ignition switch switched on? I hear a fairly loud squawking noise when I switch on my ignition, but I think it might be coming from the fuel pump. I'll check today if I hear any sound from the Bosch CDI box.

 

Actually Julian, the symptoms I'm experiencing definitely do sound related to a bad fuel pressure regulator. I'll make sure to check my fuel pressure. Thanks!

Did you just continue using your Malpassi or did you go with an aftermarket fuel pressure regulator?

 

Thanks JulianMerak and 71Satisfaction. I'm going to check fuel pressure and my accelerator pump diaphragms and springs. I'm betting my problem is related to one or possibly both of these.

Steve