Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › 84 Suburban Idle issue › 84 Suburban Idle issue
Some Edelbrock AFB type carbs are not “chrome finished”. They are either brown or or shiny, not actually chromed. Yours looks like it was shiny but it’s just dirty from off roading. The throat looks fairly clean.
I think your low voltage is from low idle speed. This is corrected by eliminating vacuum leaks, correcting ignition timing with a light, cleaning or replacing fouled spark plugs, replacing ignition components as needed (ignition wires, cap and rotor), and last but not least, adjusting idle speed/idle mixture.
There are different PCV valves for 350 Chevies. You have to make sure you have the right one. If the PCV system is operating correctly, you have a wee bit of vacuum at the hose that is supposed to go into the air cleaner. With that aftermarket air cleaner, it may routed under the air cleaner. Disconnect it and see if the vacuum will hold a piece of paper. If it will not, check the system for leaks. Check the system to see if it is sucking oil. Start with the line from manifold vacuum to the PVC. Is there a lot of oil inside?
Most vacuum leaks on your engine can be found without Carb cleaner or propane. Just disconnect the vac line from the carb and check for vac with your finger. (Manifold vac is present at idle. Vac lines connected above the throttles may have vac when you goose the throttle and not at idle). When you’ve verified vac at the source, reconnect the vac line and check for vac at the other end of the line. If vac is absent or less, the line is leaking.
You may have a leak between the carb and the intake manifold. That looks like an aftermarket aluminum manifold. Does it have a brand name on it? This is big problem area because the fellow who installed aftermarket parts may not have matched parts up correctly. Most aftermarket manifolds accept both kinds of carbs, “spread bore” carbs like the Q-jet as well as “square bore” carbs like the AFB type or Holley. If you have a manifold that accepts both types, it will have 8 bolt holes, for both bolt patterns and you need an Edelbrock adapter plate or you get a big vac leak. You can see if the 4 nuts holding the carb are tight (do not over torque them – the lock nuts should hold them in place).
I think the follow who sold you the Chevy must have had stuff like a power amp, a sub-woofer and maybe a security system hooked up to the switches and wires. I would remove all of that one piece at a time. If you want to install an amp or something later, it will be easier to run new wires and so on than to try to hook stuff up to the “rat’s nest”. In the course of taking that out, you may find something he’s loused up and fix it.
That MSD unit is probably working fine if it’s hooked up right.