Arthur - Thanks for the great posts on this topic; your time is very much appreciated here. Related to this issue, can I successfully test the hard plastic vacuum lines with a MityVac, or should I just replace them as a good practice, in the same way as we replace all the rubber vac fittings due to age? I just went through my '93 M104 2.8L and replaced all the rubber vacuum parts and now I am wondering about the hard plastic lines.

I am also learning to decode the vacuum parts chart in the StarTek EPC, huh, that's a chore. Many of them don't match up, either in shape or ID, with what's actually on the car. What looks like a pre-formed elbow is actually just bent tubing, and vice versa.

Thanks!!!! Pete

The plastic lines are either cracked or they aren't..most leaks are usually where the the rubber lines slip over the fittings/nipples at the ends. They must make a snug fit. Mnay times you can just cut off an inch or so and re-install the line for a better fit.
If a plastic line is gone, you will readily see it cracked/snapped.

Most common plastic fail ones are under the front engine cover [ EGR/AIR feeds] and the rubber one on the FP regulator.
The regulator one can cause the most problems b/c it not only causes a vac leak, but it also causes the reg not to control the FP at the correct PSI, so you wind up with adaptation codes/problems from too high a fuel pressure AND lean a/f mix from the vac leak...the ECU does not know what the hell is going on...:)...it tries to correct for both faults...rich/lean/rich/lean...

Which is why we always go to the reg as a first check when we have adaptaton codes popping up. The FP on these MUST be spec b/c the injectors are timed open by ECU demands at that spec .

I closed up the valve cover.
Removed vacuum line from Fuel Pressure Regulator, no fuel coming thru at idle.
re-checked several vacuum lines, disconnected and re-attached to feel how snug they were. They all seem good.
Restarted car, it was rough for about 5 minutes, burned some residual oil that seeped down from cylinder # 1 plug cavity.
I cleared all codes then disconnected battery for 5 minutes.
Reconected battery, took it on the highway and now idle is smooth as glass.
Either the dislodged valve cover seal at cylinder #1 was culprit of vacuum leak or there was a leak in one of the vacuum lines that I closed.
In any case, I am now idling smooth.
Thanks to all for inputs.
(also posted in oil in cylinder #1 valve cover cavity)

Go back after a few days and check HFM module.
B/C you took the bat off, you have re-set the memory back to mean.
If adapt gets back to limit, you have not solved the problem.

Dalton Code Reader
 

Arthur,

I was reading some of your posts and could not access the page that instructs as to how to build your code reader for a 1994 E320 with 124 chassis.
Do you have these instructions handy?

Much obliged.

Russ P

Russ - As far as I know, Arthur is not posting to the forum any more. Here is another location for the tool. Click this link and go all the way to the botoom and read 'home brew scan tool':

http://www.k6jrf.com/MB_X11.html

There is a ton of good information in those webpages BUT they are specific to his car and so many of them may not apply to your 124.

At the very bottom of that same webpage is a link to the codes themselves. You will need that info also. I believe your 1994 E320 is the HFM-SFI M104 motor so you need to look in the section of that code manual for your specific car. Hope this helps! Pete

That's a dead link. The following link should get you there:

http://www.mbworld.org/forums/attachments/e-class-w124/169180d1257095000-w124-fault-codes-fault-code-scanner.pdf