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.
Spray carburetor cleaner through each passage, the path from the float bowl to the accelerator pump is usually short.
Was that 8 to 10 years ago? If gasoline stays in the carburetor too long during storage, it gums up. You need to drive more or clean the carburetor every few years.
Synthetic rubber, like neoprene. There should be information in the owner’s manual acknowledging the use of E10. This is from a 1983 Chrysler owner’s manual.
Note that it states if you are dissatisfied with the performance using E10, you should use 100% gasoline. And that fuel tank additives can damage gaskets and seals, but people use additives as a cure-all.
Get a 0–10 psi fuel-pressure gauge and a fuel-rated T-fitting and hose sized to fit the existing fuel line…
Locate the mechanical fuel pump on the passenger side of the engine, near the front of the cylinder head…
Install the T-fitting inline between the pump outlet and carburetor inlet… Keep all connections tight and secure…
Start the engine and read the gauge at idle… Specification is 2.8–4.3 psi (I think, but check your manual to be sure)…
Increase engine speed to approximately 3,000 RPM while observing the gauge… Pressure should not drop… A drop points toward a fuel-delivery problem, potentially the pump or a restriction in the supply system… If the pressure is to high it can over power the carburetor needle-and-seat system…
This is just part of the diagnostic process and will either confirm proper fuel pressure or point to a problem with the fuel delivery system…
