Fuel accumulator

[presence]

I have a 450sl 1977, chassis 107. I believe the fuel accumulator is the problem. Will start but takes a number of turn overs and pumps of the gas. The warmer the car is the worse the problem. same problem for a year with no worsening. Fuel pump, hoses, distributor cap, plugs just replaced with no change.
I can't seem to find the part for this year and chassis.
Any thoughts are appreciated.

[cth350]

It's a CIS car, you want to invest in a CIS fuel pressure testing kit. Mid-priced ones work fairly well if you are handy.

There are spec's someplace for fuel pressure when the engine is cold & hot. There's probably a spec for how long pressure should hold once the engine is turned off, but's it's been a while, so I forget.

It's the kind of thing where you have to be patient and go by the specs, in a given order to ensure correct idle, CO%, pressures, ignition, etc. If you get through all the tests from one end to the other, something sure works.

-CTH

[daantjie]

Hard hot starting can also be the auxiliary air valve (air slide) stuck open. At engine full hot it must fully close but after all these years original ones get stuck open letting too much bypass air into the idle circuit. Does it idle rough too when hot, or just the starting that's difficult? Be warned the auxiliary air valve is eye wateringly expensive if you can find a new old stock one. Old ones can be cleaned with varying degree of success.