Economy Gauge poll for M103 owners - PeachParts Mercedes-Benz Forum

RBYCC · #1 08-25-2009, 10:06 AM

Quote:

Originally Posted by ps2cho

I checked the end that attaches to the intake manifold and it appeared fine...so the only other end to check is at the instrument cluster. I really didn't want to pry it off because it never quite sits as flush once removed due to the warping with time. I guess I gotta just bite the bullet and try it.

...although I doubt something as small as this could be my poor MPG, right?

Vacuum leak could cause poor running and mpg.

You don't necessarily have to have a leak in hose from the manifold to the gauge.

The gauge will react to any loss of manifold vacuum regardless of where it is.

Disconnect the hose at the manifold and install a vacuum test gauge.
The readings should give you an indication of any potential problem.

I tee off from behind the dash econ gauge and feed a vacuum/boost gauge.
If you have a tight system, the gauge should react quickly and read dependent on true engine vacuum.

ps2cho · #2 08-25-2009, 11:41 AM

Quote:

Originally Posted by RBYCC

Vacuum leak could cause poor running and mpg.

You don't necessarily have to have a leak in hose from the manifold to the gauge.

The gauge will react to any loss of manifold vacuum regardless of where it is.

Disconnect the hose at the manifold and install a vacuum test gauge.
The readings should give you an indication of any potential problem.

I tee off from behind the dash econ gauge and feed a vacuum/boost gauge.
If you have a tight system, the gauge should react quickly and read dependent on true engine vacuum.

Yes. That's what I thought. It's just odd because I've done all the vacuum hoses....so I'm kinda at a loss. I even used the O2 sensor and plugged each of the vacuum ports then undid each one individually monitoring the O2 sensor for any change...and there was no difference.

I'll give the vacuum test gauge a try though and see what happens.