I’ve asked before, and responded to the advice I’ve gotten, but I’m back at it. My '87 (2WD, gas, carburetor, 5-speed) lags. It really matters when I have to start from a stop: I have to give it gas before I let out the clutch because the load on the engine causes a stall. The delay annoys people behind me and can be dangerous uphill. I take a roundabout route through the neighborhood on flat streets before I go uphill.
I replaced the fuel pump, filter, fuel lines, plugs, coil, distributor, cables, air filter, oil and filter, and rebuilt the carburetor. Every time I buy gas I add a bottle of motor treatment or gas cleaner.
The choke works. I’ve drowned the throttle cable and all the exposed workings outside the carb in spray lube.
When I work the throttle by hand when it’s off and cold I see no gas coming into the carb. I begin every day I drive by priming the carb with carb cleaner or starting fluid; I don’t need to do that the rest of the day. Because I installed a new accelerator pump and auxiliary accelerator pump when I rebuilt they’re new and I expect them to work. I took them off the other day (and lost the spring and 2 bolts - grrr) and they look okay. I suspect the problem is earlier in the system. How do I trace back to see where the gas is first not-getting?
I have a mechanical pump so I can take it off and work it mechanically; I’ve done that. I’d like to be orderly and efficient.
The accelerator pump is inoperative. Replacing the diaphragm is only part of the repair, the nozzle and check ball must be cleaned. There are passages inside the carburetor housing to be cleaned.
It is not unusual to need to clean the accelerator pump after a year of storage.
Apparently, this is the reason people sell their auto collections; they don’t have time to clean carburetors. (See old mechanic retires thread)
I had a probleml like that and I had to properly set the float level to fix it. The fuel wasn’t reaching my pump piston because the slot was higher than the fuel level. Yours is a different setup if it’s a diaphragm but the float level may still be a problem.
I would also check for vacuum leaks. Cracked/loose intake manifold bolts, vacuum hoses, and EGR vacuum modulator leaks. also, I found this. I think it’s the one you have.
With no gas when throttle opened there’s a problem with the accelerator pump, at least. I’d also check the float level and vacuum leaks. Seems the fuel pump works if the truck runs once started.