economy gauge - PeachParts Mercedes-Benz Forum

E150GT · #1 03-12-2007, 07:52 PM

should the economy gauge sit completely to the left in the black at idle? sometimes it does not sit all the way over at idle. i hear this might be a vaccum leak. does this mean its a vaccuum leak for the gauge or for something else and the gauge is just telling me? i did a search and didnt come up with a definitive answer. THANKS The car is a 420sel 1986

spqrzilla · #2 03-12-2007, 10:44 PM

The gauge itself is essentially a vacuum gauge because it measures intake manifold vacuum. The idea being that a higher intake manifold vacuum means that you have your lead foot deep in the pedal indicating a less "economical" use of the throttle.

raymr · #3 03-12-2007, 11:31 PM

Mine is all the way left and raises slightly when the A/C is on. Do you see a difference between A/C and non-A/C?

david s poole · #4 03-13-2007, 09:49 AM

at idle it is a measure of manifold vacuum and should be all the way left unless you have vacuum leak issues.be sure to check the three way connection going thru the false firewall by the booster.that baby gets hard as a rock and leaks.

E150GT · #5 03-13-2007, 10:25 AM

Ill be sure to check out that line David. My gauge is usually to the left at idle except when the ac is on. Sometimes when it is not always to left at idle i can rev the engine a little and it will go over to the left all the way and if i rev a little higher, it will move towards the red.