Where to tap boost for gauge install? W124 300D - PeachParts Mercedes-Benz Forum

cscmc1 · #1 04-12-2008, 04:26 PM

I KNOW I have read this somewhere, but searching isn't helping me find it. Where's the best place to hook up a VDO boost gauge on my 92 300D? Any tips on fittings to use? Many thanks, all!

sixto · #2 04-12-2008, 04:35 PM

I don't know about best but pretty convenient to tap the line running from the intake manifold to the ALDA. Downstream of the overboost switchover valve if there is one.

Sixto
87 300D

bobodaclown · #3 04-12-2008, 06:02 PM

Coming off the cross over tube you can place a "T" there or by the ALDA. I think there's an empty space on the cross over tube.

Off the subject. Did you get the codes?

#4 04-12-2008, 06:08 PM

There is a test port nere where the ALDA gets its pressure. It's metric threads.

cscmc1 · #5 04-12-2008, 06:22 PM

Quote:

Originally Posted by bobodaclown

Off the subject. Did you get the codes?

Thanks for all the tips, fellas. I will need to hit the hardware store for a fitting for the gauge anyway... it was lost long ago.

On the codes, yes. I had a multitude of them!

5
15
4
2
3
11

I cleared them all since I found a vacuum leak (must be somewhere in the climate control system as anytime I hook up the vacuum line that runs through the firewall near the battery, the vacuum drops to nil). I disconnected that and put a golf tee in the vacuum line, and now the car drives much better.

Now I need to go look up those codes!

bobodaclown · #6 04-12-2008, 06:50 PM

Attached are the codes.

bobodaclown · #7 04-12-2008, 06:55 PM

Quote:

Originally Posted by cscmc1

Thanks for all the tips, fellas. I will need to hit the hardware store for a fitting for the gauge anyway... it was lost long ago.

On the codes, yes. I had a multitude of them!

5------EGR Vacuum Transducer
15-----Boost Control Pressure
4------EDS Control Unit Sensor
2------Fuel Rack Position Sensor
3------Airflow Sensor
11----possibly same as 5.

I cleared them all since I found a vacuum leak (must be somewhere in the climate control system as anytime I hook up the vacuum line that runs through the firewall near the battery, the vacuum drops to nil). I disconnected that and put a golf tee in the vacuum line, and now the car drives much better.

Now I need to go look up those codes!

There is susposed to be a vac leak on that line. It vents to atmosphere. I think by the brake booster is the line that controls the HVAC system.

Also review this post:
W124 93 300D 2.5 Boost Problems (I too am stumped!)

cscmc1 · #8 04-12-2008, 10:45 PM

Quote:

Originally Posted by bobodaclown

There is susposed to be a vac leak on that line. It vents to atmosphere. I think by the brake booster is the line that controls the HVAC system.

Also review this post:
W124 93 300D 2.5 Boost Problems (I too am stumped!)

Huh... plugging that "vent" line gives me ideal performance. What the heck??? W/o plugging it, I get no vacuum to the flapper and EGR, so no boost.

bobodaclown · #9 04-12-2008, 11:23 PM

Hey I'm sorry I don't want to rain on your parade. If its working and your happy. So be it.....Sorry..LOL

cscmc1 · #10 04-12-2008, 11:29 PM

Quote:

Originally Posted by bobodaclown

Hey I'm sorry I don't want to rain on your parade. If its working and your happy. So be it.....Sorry..LOL

No, no... I appreciate your help! I just can't get my mind around the problem here. I do think my ACC has been affected, though; the temp control wheel doesn't have much effect at all now, whereas it did before. I'll have to fiddle more tomorrow!