PeachParts Mercedes-Benz Forum - View Single Post

pawoSD · #2 07-02-2009, 12:08 PM

Quote:

Originally Posted by MattBelliveau

So maybe I should also be looking at an engine temperature sensor and maybe a Idle Air/Speed Control Valve . Is there anyway to test any of these parts?

Yes, put a multimeter that does ohm readings on the pins of the temp sensor (test the 4 pins 2 at a time, criss cross....there are two identical sensors in there for two different computers)

The idle valve can be tested just by giving it 12 volts, if it clanks and moves the little valve in the opening, it works. It'd be good to drown it in brake cleaner to get all the gunk out of it. The hoses connected between the idle valve and engine/intake are also likely hard and need to be replaced to prevent vac leaks (which might explain your 2000rpm idle)....lots of rubber parts under there, as many should be replaced as possible. Gassers are sensative to vac leaks.

Where does you economy gauge sit while in park and drive without pressing the pedal? In park with the A/C off it should be essentially pegged in the black, in drive it should move a couple need widths off the peg. With the A/C on it should move over towards the red a bit more. If its near or in the red all the time then you have some big vacuum leaks.