This is a 1980 450SLC.

The car had been sitting for 3 years.I have replaced the filter,sparkplugsand pump. The old pump was siezed up pretty badly. Now the car starts but runs very poorly and is cutting out at the slightest touch of the pedal. I Can't get it to rev very much at all. 2k rpms max and it takes a long time to work it up that high even. It just stumbles a lot when I give it pedal. I also checked to make sure the tank wasn't clogged(i bypassed it and ran the tank hose directly into a gas jug). THE FUEL PUMP IS GETTING HOT ENOUGH TO BURN MY HAND! Where could this problem be hiding? What should I check?[/align]

 

Possibly fuel (light end loss after3 years) but more likely you have a vac signal line perished / off somewhere.

Where did the "new" pump come from?
Unless you can vouch for it being OK I don't believe it should be as HOT as you indicate. Fuel line pressure is very important so you need to verify that this is OK if the other ideas prove negative. A reason for getting HOT could be a blockage. post pump. Is the return line working OK?

Stuart

 

I agree with snanceki. Check your return line. Check your fuel filters. The pump should get a bit warm, thats normal. But it shouldn't get hot enough to burn your skin. The pump is probably overworking, somehow. The pumps are designed in general, not sure if this is true on an older model car, but my '88 is this way, the pumps are designed to shut off if the fuel rail has enough pressure, or meets too much resistance, due to blockage, etc. It might not be this way with your car however. Something that is very very rare, but I have seen a half dozen times or so, is that you could, somehow, have a vapor lock somewhere in your fuel rail or carb/TBI. If your vehicle has a TBI, check fuel rail pressure. I'm not sure exactly what it should be, but it should be around 7-8PSI. Check and see if your injectors are spraying and atomizing fuel properly, assuming its TBI. If its a carb. engine, check your floats and journals. Sometimes those damn mud wasps and other bugs like to plug up venturis and journals and any other opening they can with mud and other debris, if the vehicle has been sitting for awhile.

I'm thinking that the car is TBI, correct? Most carb. engines have mechanical fuel pumps. Mostly, sometimes not. If it is TBI, the injectors should be spraying a nice constant stream of fuel, not intermitant, or pulsating.