Serious fuel problem on 82 308

Let my QV sit last year for about seven months before starting it. Ran very poorly and finally quit after about 5minutes. Found I had corrosion in one of the coil/coil wire connections and was only running on four cylinders. Intake hose had quite a bit of raw fuel setting in it. Pulled the hose and soaked up as much fuel with paper towels as I could in the throttlebody, pulled the plugs and replaced. Are you sure you’re running on all eight cylinders? You can tell within 15 seconds by simply touching each one of the exhaust headers. My front header was cold as ice.

other thing I should point out is this unburnt fuel ends up in your oil so when you figure it out you’re going to want to do an oil change also

 

Is the car running ok? You do not mention that, so your car starts and runs but is dumping fuel into the plennum/hose?

The fuel distributor has 8 O rings on a center plunger that meter fuel into each fuel line. The plunger itself has a couple of o rings that prevent fuel from leaking out of the distributor into the plennum. After sitting for a long time, these dry o rings might well have been a bit stuck and tore loose with the plunger movement when reinstalled. Hence there copuld be leaks. There is also a large rubber diaphragm in there, but that would not be damaged by just sitting on your bench.

You could try the following:

Remove the plennum hose so you can see in the plennum. Jump the fuel pump (with the car not running), and there should be no fuel going through the system at all when the engine is off and the plunger is in its rest position. If you see some fuel dribbling down into the plennum, the bottom plunger seal o rings are leaking. If so, that would explain how the car might run fine, but there is a fuel leak at the base of the plunger into the plennum.

You can get the rebuild kits for the fuel distributor on ebay. You would need a micrometer to measure the pre dissassembly plunger nut depth so you could reinstall with the same plunger position, which is very important, miniscule differences in the plunger mounting nut depth can mean the fuel metering is off and cause all sorts of running problems. You have to split the distributor to get at the plunger assembly, and then do the diaphram while in there, and that can be a delicate process and by many enturst a rebuilder. But doing a plunger seal renewal and dist rebuild is in the realm of a careful handyman, there are you tube videos typically for Mercedes cars of the period using the same Bosch systems that are exceptionally helpful.

Some pictures of the plunger assembly fyi to see the seals than might be leaking. My car is the 3.2 engine, there may be slight differences in earlier cars, but I think the key aspects of the fuel distributor are the same.
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On the other halve of the distributor there is also a black membrane that can be punctured by ethanol. This is from my 400i ( so two 6-cyl distributors instead of a 8-cyl one), but this gives an idea of what's involved:

"Plunger sleeve" with filters and o-rings
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Similar halve to the above V8 one (ancillaries not installed yet)
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Other halve with the membrane.
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