1986 Peugeot 505s 2.5 TD

[jerro]

Hi good people, having solved the cold 1st start of the day smoke issue by advancing the injector pump timing a little my Pug is running really well. This question is about the cold start `assist` unit next to the injector pump that is supposed to pull the throttle linkage back a little when cold to increase the rpm`s until the engine temperature has gone up. At the front of the `unit` the cable runs straight to the throttle linkage and at the back there is the inlet and outlet pipe which i assume must be for the radiator coolant to pass through. I`m also assuming that there is a thermostat type valve inside. Mine does not seem to be pulling the throttle linkage back when cold. You can see it all in the photo (i hope!).2 questions please, what is this unit `called` and can i take it off and clean it to see if it is jammed or should i get a new one?--Thanks as always---

[JunktionFET]

I forget its proper name but it is probably more accurate described as the "cold start advance" mechanism. Its primary purpose is to artificially advance the injection timing when the engine is cold, thus ensuring quicker starts and better operation while the engine is cold. Its secondary purpose, as you can see, is to prop the throttle open a bit to increase cold engine idle speed.

Are you positive that it isn't doing anything? Verify my taking precise measurements of its extension when the engine is dead cold versus at operating temperature (cooling fans cycled).

[JunktionFET]

I'd like to further iterate... don't measure how much the throttle lever has moved. Measure the device itself.

From the look of things, your entire throttle setup might need some adjustment once you verify this device is/isn't working.