sdk50

I purchased a 1979 928 that has been in storage, ran fine when stored. He got it out of storage will barely run. He has replaced fuel tank, fuel pumps, and filter. I've replaced fuel distributor. Has good spark, I don't know if he used aftermarket fuel pumps or not. It really seems like a fuel problem. I'm wondering if the pumps are aftermarket if I'm getting proper pressure and or volume. Any help would really be appreciated.

SMTCapeCod

You need a set of diagnostic guages to check the pressure, but you can doa volume check by just running power to the fuel pump and letting it pump into a container so you can measure its output/min.
I don't have the spec book handy, I think '79 is around 1120cc. You should also make sure you're getting adequate power output from the alternator and adequate power to the fuel pump(s). Precautions after storage include changing the fuel filter, checking the ports on the warm up regulator for debris. There is also a filter/strainer at the inlet to the fuel distributor that sometimes fails due to buildup and etc.
Given the age and the storage, a good search for vacuum leaks and failed rubber parts is probably in order too.

checkmate1996

When replacing the fuel distributor, I presume you adjusted the air fuel mixture screw.

hupp

I agree with the last two posts. Before you start swapping parts, accurately diagnose the fuel delivery and fuel control and system pressures first. This is relatively easy, but you must follow the instructions in the WSM. I would also inspect the "green wire" which is routed between the ignition module and the ignition distributor at the front of the engine. Should be in good condition with no insulation damage. If these things check ok, some things to verify include:
- proper fuel air mixture
- proper auxillary air valve operation
- no vacuum leaks
- Cold start valve not leaking
- Air sensor moving freely
- ignition timing to spec.