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Hi. I have a 82' 380sl in mint condition however it exhibits a problem when starting on a warm engine. If the engine is cold it starts perfect, in fact too quickly but when I have run it round the block a few times, stop the engine and try to start it agin, it takes a while to kick over, like about 3 - 4 seconds. IT has just been fully serviced. It had the problem before the service but it looks like the mech could not fix it....<br> <br> Thanks in advance. Cheers
 

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There are many reasons why the engine would be difficult to start, the fuel filter and fuel accumulator may be at fault or the pump may be the cause.<br> <br> The problem occurs particularly after the engine has been running due to the pressure relief valve located at the back of the pump inside. It is activated by a small spring and a metal cone which in time it sticks and do not allow pressure to be relieved.<br> <br> As the pump is driven by a permanently excited electric motor the pressure is reduced. After stopping, the fuel accumulator maintains pressure in the system to facilitate starting and with this pressure if the valve is stuck it develops an inner leak.<br> <br> If you tap the pump firmly it releases the pressure valve and the engine starts again. When the tapping becomes frequent, is time to replace the pump.<br> <br> Mercedes know this and they provide a Check Valve which to be installed by replacing the existing hollow screw to the pipe connection to the pump, effectively providing a secondary pressure relief valve and avoiding having to buy a new pump.<br> (Check valve $12.98, cap nut $1.49 - pic attached) <br> <br> <br>
 

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David,<br> <br> Check the site below, select Catalog on Line, enter year and make, select model, click on Fuel Delivery then select Fuel Pumpm Check Vale and dont forget the Check Valve Cap Nut (you need both).
 

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Hi Rasputin,<br> <br> I have finally got around to replacing the check valve, Cost $51 australian and this has not helped at all. The last few days, or what prompted me to do the replacement was a slight hesitation at low engine rev or just starting at the lights. Sounds like a miss with a little loss of power. This seems to be getting worse and has started after I got some very cheap High Octane UNleaded fuel. Could the fuel be dirty?<br> <br> I think you said the accumulator was the next thing to look at, that costs $500+ in australia and do not want to do this for nothing.<br> <br> Hope you can help with all these questions.<br> <br> Cheers
 
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