Sounds like the same problem I had.......EGR was not fully closing. Please check that if your's has one. I've been out of the loop for a while (many trouble free miles (fingers crossed), so I hope you're car has one.

__________________
RT


1984 300D---Sold
1995 E420 - 106K - Brilliant Silver Metallic/Orion Gray --- Sold
1984 300SD - 151K Manganese Brown Metallic/Mostly Black --- Sold
1982 240D - 79K - Manila Beige/Palomino---Sold

Yours was not blocked off? :SHOCK:
You make a very good point, it is possible.
The EGR is a breakdown waiting to happen.

Whunter,

I have a brand new line from the Banjo bolt to the Crossover on the firewall. The line from the Crossover to the ALDA looks clean.

The top of the Crossover valve has some kind of rubber goo on it. I don't want to peal it off, just in case it's covering a hole or something.

Would it be a good test to run direct from the Intake manifold to the ALDA to see how the performance is affected?

I just don't want to do anything that will mess up the car.

__________________
1998 W202 C230 - The money pit of late.
1984 W126 300SD (356,800 miles) Gone to the wrenchapart
1984 W123 300D Gone to the wrenchapart
1972 W108 280SE 3.5 (sold but not forgotten)
1986 Buick Grand National 3.8l Turbo (86k miles)
1966 Glassic Model 'A' Replica http://www.glassicannex.org

http://banners.wunderground.com/weat...Round_Rock.gif

So, would it be a good idea, performance wise and for off road use only to block off the EGR tube? At least as a test...say using some heavy aluminum plating?

__________________
1998 W202 C230 - The money pit of late.
1984 W126 300SD (356,800 miles) Gone to the wrenchapart
1984 W123 300D Gone to the wrenchapart
1972 W108 280SE 3.5 (sold but not forgotten)
1986 Buick Grand National 3.8l Turbo (86k miles)
1966 Glassic Model 'A' Replica http://www.glassicannex.org

http://banners.wunderground.com/weat...Round_Rock.gif

1) The valve has three ports. The top one is normally capped off - you can leave it alone.

2) Yes, you can temporarily bypass the valve and see if there's any change. Also you want to try to blow through the valve - if you can't, it's plugged, and needs to be cleaned or replaced!

That's a roger, Roger. I did this on my 603's and my 617 as well. Photos of before & after are at this URL:

http://www.meimann.com/images/mercedes/OM603_intake/



Here's what a 603 looks like with the, uh, 'heavy aluminum plating' installed:

If someone put goop in it, the crossover valve can NOT work.
Picture attached showing cap.

Attached Thumbnails

 

Minor correction. The cap can be sealed, or not - it doesn't matter. When properly connected (manifold to bottom port, ALDA to center, cap on top port), and the overboost switch triggers, the center port switches from default position (connected to the bottom, manifold pressure) to the top position (capped off). My 617 refuses to build over 15psi even with the wastegate disabled, so I bypassed my valve permanently (although I don't recommend this unless you understand the risks involved.)

I recommend using caution bypassing the over pressure switch. I had an issue with my '85 300D where right before it shifted and at high speed runs it would "cut out". I did some troubleshooting and found the hose that signals the wastegate had a hole in it and it was pressurizing enough to trip the over pressure switch. I can see where some engine damage could be done if the hose at the wastegate leaks badly enough to prevent it from opening up.

__________________
Jim

Thank you for the correction.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

Since I started this thread I figured that I would nudge it back into the direction it was intended to go before it flew out one of those open "doors" :p .

I tweaked the ALDA and it did help. The problem is really a morning problem so I will have to see if the ALDA tweak really helps the real problem in the morning when I start out of the drive.

Thanks for the input. BTW, would any of you be interested in a 1984 380SEL? It is complete but has no title. My friend wants $300 for it. It supposedly has a bad fuel distributor.

Hey, I hijacked my own thread! :p

Kevin

I was in this identical position once and the Forum convinced me my engine was dead. The good thing was I got a new 87 300D out of it, because thats what I bought instead of a new engine!
Later on, I found out that the Fuel Pump was toast. They do that sometimes because of incosiistent fuel quality and low sulfur in today's modern diesel....3 ou of 5 barrels were dead, the ALDA had a BAD leak, other parst were dead
...

Forgive me for a minor hijack of the thread, Jim, but was this on the black '85 I'm driving? I'm a little embarassed, but for the life of me, I've been unable to locate the "overboost protection" valve on this car. I wasn't troubleshooting anything, just trying to get acquainted with everything under the hood. Am I missing something obvious?


-- eskimo