W116 280SE fires but then dies instantly

[NormW126]

I'm having a problem with the 1977 280SE I'm trying to get running. I've now refurbished the fuel tank and got a spark... finally! So I tried to fire it up today (the car has been sat in the garage since the mid 90s), it sort of fires up very briefly but then dies immediately. And I also hear a strange sort of hissing noise. Hard to place where it's coming from, but roughly somewhere under the air filter housing, probably from the fuel distributor?

Also the fuel pump only runs when the flap thing in the metering unit is pressed, either by hand or when cranking. I thought I should buzz at least briefly as soon as the ignition is turned on?

Anyone have any ideas?

Thanks
Norm

 

[Marku]

Not to sure about the intricacies of the 280. I guess its a K-jet? Sounds as though you have an air leak. Check all the hoses if you haven't replaced them which would be advisable anyway. The fuel pump will stop as soon as it senses the engine not firing. You might get a more specific answer from W116.org

 

[NormW126]

Thanks Mark. Yeah I've posted on that forum already too.