Following the advice of the forum, I'm slowing working on cleaning, repairing and tuning the fuel system on my 85 300D. I've had her for only a few months, but we're getting to know each other pretty well. Just swapped the oil cooler lines among a bunch of other little things. First of all, thanks to you all for your knowledge!

So I pulled out the banjo bolt off the intake to see if it needed cleaning, and it looks like someone has crushed the end of it, effectively rendering it a plug. Any reason why anyone would do this? Also it looks like the air line coming from the banjo bolt is bypassing the switch and is hooked up directly to the ALDA. I can't even find the switch that's supposed to be mounted on the firewall...







My first instinct is to replace this right away! =) I assume this could easily be affecting power, which seems low on the car right now.

Any ideas or advice would be greatly appreciated. I couldn't find anything like this when searching the forums. Is there a part number for the banjo bolt to order at the dealer?

Cheers,
Sean
85 300D, slowing getting back to stock...

The overboost protection valve is pretty obscured on the w123, you have to lean over to see it.

What has happened to that bolt is pretty weird. No wonder, if someone played around trying to solve a low boost situation and ran the sensor line right to the ALDA, thinking maybe the switch was defective.

A competent dealer parts guy should be able to find that part number easily.

Or you could ask in the Used Parts for Sale and Wanted subforum is someone has a spare banjo bolt and valve lying around from a parted motor.

__________________


Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

Either it had an encounter with a bona fide ID10T and lost or someone did that to make the car slow on purpose. Maybe someone's teenager was driving it and the parent knew enough about the car but not enough to do it properly. I'm going with the ID10T theory.

I suppose you could cut off the mangled end and reinstall it for now.

__________________
1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge

Thank you guys for the replies. Yeah I'm trying to understand why someone would do that. I've since replaced the bolt, and the car does seem to be running better but not as different as I'd expect. I think the next step is to get a boost gauge on the car and see what's going on there. Also the ALDA cap has been removed, so I'm worried they started tinkering.

Cheers,
Sean
85 300D
Ojai, CA

The line from the intake manifold should run to an overboost solenoid on the firewall then continue to the ALDA. Remove the two lines from the solenoid, remove the two screws that secure it then see if you can blow through it. If you can't easily get air to pass through then it's clogged like mine was and you need to use MAF cleaner on it. Some people have used brake or carb cleaner but I like to go easy on the plastic. You sould notice a huge difference in engine response if that's the problem.