Vacuum tests on 300CE
 

What is the best way to check for vacuum leaks on a 1990 300CE
with a mity vac?
Any advice would be great.
thanks
bshah@satx.rr.com

Do you have a running problem? More info!

Vacuum leak tests in 300CE- for ILUVMILS
 

I have a miss and had replaced the ignition wires.
I also replaced the EGR valve with a new gasket but I did
not replace the fitting on the pipe that connects to the EGR, just
used the existing one.
I found the switch over valve had a leak, so I replaced that also.
I tried to pull vacuum on one of the ports on the intake manifold and it does not hold vacuum. Maybe I am doing something wrong! Or does this mean I have a leak??
Am using a Mity Vac
Please advise
Thanks
barry

The various vacuum fittings on the intake manifold are good places to CHECK (with your Mity-Vac) how much vacuum the engine is producing. If you're looking for a leak though, you'll need to check the vacuum consumers to see if they're leaktight. You may also want to check any place that air can enter that's not "metered". Good luck

The automatic seat-back locks (under the seats) are vacuum operated and are likely to get lots of general abuse.

It's worth checking these for leaks.

What makes you sure that a vacuum leak is the cause of your miss?

Vacuum leaks and miss
 

I am not sure whether it is due to vacuum leak. I had replaced most of the igntiion components and it had not fixed it.
So, I want to fix this problem by making sure that there are no vacuum leaks, i did find two, so we shall see.
i also measured the voltage when I slowly push down on the mass flow sensor plate and there is quite a bit of play where the voltage does not change and then it changes.
Continue investigation.
Barry Shah