V8 Vacuum Tubing Replacement
 

As part of my troubleshooting a ‘Check Engine’ light issue in my ’94 SL500, I replaced all the small, milky-white plastic tubing around the engine… except for one line. This vacuum line goes from an ignition module (picture #1) to somewhere under the intake manifold (picture #2).

Short of removing the intake manifold (which seems REALLY silly), how do I gain access to the end of the vacuum tubing attached to the engine? The one under the intake manifold?

Cheers,
Jeff

Try to trace the vacuum line again to see if it comes up from under the mainfold to the top area. I know it's a different animal, but that exact same hose connected to the Ignition Control Module on my 190E 2.3, goes under the intake manifold and comes back out at the rear of the manifold and connects to a Y vacuum hose that is connected to a vacuum port on top of the intake manifold.

Thanks 'Red' for the thoughts. However by using a mirror, I can see it connects directly (I think) to the Intake Manifold. Problem is, the space is quite cramped and I cannot reach it from the rear.

Do I have to remove the Throttle Actuator assembly?!?

Cheers,
Jeff

I have 3 vacuum hoses that connect to the bottom of the throttle assembly. On the 2.3 4 cyl., I can reach my hand under the front of the intake and put my fingers on those 3 connections. I assumed that 1 of those was the one coming from the Ignition Control Module, but when I tugged on the plastic line I could trace it coming back up to the top of the intake.

When I removed the Fuel Distributor/Throttle Assembly, I had good access to all of the hard to get to vacuum connections.

Good luck,

Dave