My 2.5 Turbo has ADA not ALDA - PeachParts Mercedes-Benz Forum

MarkM3 · #1 03-25-2014, 11:42 AM

Greetings, new owner of a 300D 2.5 Turbo. While looking closer at IP, it became obvious that my "ALDA" is really an ADA. Not to mention the IP part# indicates a rebuilt pump (602 070 65 01) Guess someone in past put the wrong part on, or just had it handy and used it as a band-aid.

Car runs descent, kinda a slug off the line and I feel it needs a lot of throttle to maintain some hills, but I'm new to diesels. If I stomp it, it will pull strong thru each gear as long as loud pedal is buried.

Questions are:
With boost pressure line connected to the port on the ADA, WILL it increase fuel under boost conditions as an ALDA will ? (seat of pants it does seem faster with it connected)

IF it does not increase fuel under boost, is there danger of engine damage having boost but no fuel. Or just lack of power. Seems I read somewhere that a diesel would not be hurt by running lean, just less HP.

Should I just remove it, Adjust it the same way as others do the ALDA, OR try and obtain an ALDA to install. There may be one from an 603 near me,would it work in this situation ?

Thanks all !

shertex · #2 03-25-2014, 12:06 PM

That's interesting...I noticed the same thing and wondered about it on a high mileage 91 300D that some guy recently showed me.

I have a couple of extra ALDAs if you'd like to go that route.

vstech · #3 03-25-2014, 12:09 PM

Hmm, I'd think the NA IP is the biggest problem, as it likely cannot flow enough fuel to support the turbo.

find a long flat level road, and time the 0-60 it should be around 11 seconds. if it's more like 20ish then you have issues to address. another possibility is someone stuck in a used 2.5na in your car, and put the turbo manifold on it... that'd be bad.

shertex · #4 03-25-2014, 12:34 PM

FYI spec 0-60 on the 90-93 300D is 12.8 seconds.

vstech · #5 03-25-2014, 12:53 PM

thanks for that, I knew it was around 11, so it's closer to 13, and that's NEW, so a bit of age on it, and low cetane fuel, likely around 14... if it's over 18 there is a problem for sure.

Mxfrank · #6 03-25-2014, 04:17 PM

Sluggish performance on 60x engines is often caused by a blocked ALDA feed. If you look on the left side of your intake manifold, you will see a large electrical sensor. Directly below that is a hose fitting with a 3.5mm hose connecting to a plastic tube. Remove the hose and unscrew the fitting from the manifold. Chances are, it's packed with greasy material. Clean this out, then replace the hose with new. Then follow the plastic tube to the firewall, where it will connect to a vacuum switchover valve. If the fitting was packed with goop, so is the switchover valve. Use a spray cleaner with a very fine extension tube to clean the valve. When it's right, the cleaner should blow through from top to bottom. If you can't get it clean, replace the valve. Once these ports are clean, the ALDA will be able to sense turbo boost and supply the correct fueling. As a reference, my 190DT does 0-60 in just UNDER 10 seconds.

vstech · #7 03-25-2014, 11:58 PM

Yeah, it's amazing how quick the 201's are compared to the 124's.. 1200 lbs or so lighter I guess

DieselPaul · #8 03-26-2014, 01:21 PM

Are you sure you're not looking at GVWR numbers?

1987 300E automatic - 3,219lbs curb weight
1987 200D automatic - 2,884lbs curb weight (euro)
1987 250D automatic - 2,976lbs curb weight (euro)
1987 300D automatic - 3,064lbs curb weight (NON-Turbo)
1987 300D automatic - 3,197lbs curb weight (TURBO)
1992 300D automatic - 3,384lbs curb weight (2.5 Turbo)

1987 190D 2.0 automatic - 2,513lbs curb weight (euro)
1987 190D 2.5 automatic - 2,844lbs curb weight
1987 190D 2.5 automatic - 3,009lbs curb weight (USA Turbo)

Source
http://www.automobile-catalog.com/specifications.php

MarkM3 · #9 03-26-2014, 05:59 PM

Quote:

Originally Posted by Mxfrank

Sluggish performance on 60x engines is often caused by a blocked ALDA feed. If you look on the left side of your intake manifold, you will see a large electrical sensor. Directly below that is a hose fitting with a 3.5mm hose connecting to a plastic tube. Remove the hose and unscrew the fitting from the manifold. Chances are, it's packed with greasy material. Clean this out, then replace the hose with new. Then follow the plastic tube to the firewall, where it will connect to a vacuum switchover valve. If the fitting was packed with goop, so is the switchover valve. Use a spray cleaner with a very fine extension tube to clean the valve. When it's right, the cleaner should blow through from top to bottom. If you can't get it clean, replace the valve. Once these ports are clean, the ALDA will be able to sense turbo boost and supply the correct fueling. As a reference, my 190DT does 0-60 in just UNDER 10 seconds.

As far as I can tell, there is no switchover valve on the firewall. There are two I believe mounted on a partition between the engine and the passenger side fender along with two vacuum transducers. I'll use the method you suggested to clear them out.

One under the air cleaner and the other at the coolant reservoir. I have cleaned the port where the ALDA/ADA connects and associated hoses.

Still need to pull off the hard plastic tube that runs over to what I think is a boost pressure sensor thats part of the EDS system ?

MarkM3 · #10 03-26-2014, 06:05 PM

Quote:

Originally Posted by vstech

Hmm, I'd think the NA IP is the biggest problem, as it likely cannot flow enough fuel to support the turbo.

find a long flat level road, and time the 0-60 it should be around 11 seconds. if it's more like 20ish then you have issues to address. another possibility is someone stuck in a used 2.5na in your car, and put the turbo manifold on it... that'd be bad.

I hope that is not the case here. According to this:EXTREME OM602.962 Rebuild Parts List

the IP should still be for a Turbo. Not to mention I've ran across discussions that there are no internal changes in the pumps. SO hopefully neither of those scenarios are true.

BTW, did a 0-60 using stopwatch. A touch over 13 sec. Will try it with no boost pressure feed to the ADA.

Have noticed MPG seems a little worse this time around.

winmutt · #11 03-27-2014, 12:01 PM

Are you sure its a turbo engine?

MarkM3 · #12 03-27-2014, 03:28 PM

Quote:

Originally Posted by winmutt

Are you sure its a turbo engine?

Ummm, why would there be any doubt from what I've asked ?

Yes, I'm REALLY sure it's a Turbo engine.

OR to be exact, it is at least an engine with a Turbo. Just in case someone swapped an N/A into it and then added the Turbo.

I imagine the only way to tell if it's a turbo block is by engine number or ?

winmutt · #13 03-27-2014, 03:43 PM

Quote:

Originally Posted by MarkM3

Ummm, why would there be any doubt from what I've asked ?

Yes, I'm REALLY sure it's a Turbo engine.

OR to be exact, it is at least an engine with a Turbo. Just in case someone swapped an N/A into it and then added the Turbo.

I imagine the only way to tell if it's a turbo block is by engine number or ?

Head number would suffice I think. It just got me thinking, the IP if you were going to swap it why would you leave the ADA on. But what if it was really the whole engine swapped in? Without more fuel that turbo is doing very little for you.

This thread demands pics.

MarkM3 · #14 03-27-2014, 05:07 PM

Quote:

Originally Posted by winmutt

Head number would suffice I think. It just got me thinking, the IP if you were going to swap it why would you leave the ADA on. But what if it was really the whole engine swapped in? Without more fuel that turbo is doing very little for you.

This thread demands pics.

I had the same thought, as to why would they not use the ALDA that one would assume was on hand.

Pic uploaded is not from my car, but does show what I was speaking of earlier.
Would be really nice if these cars came with a boost gauge stock, along with a wastegate controlled by boost pressure.

Credit to GSXR for the image.

MarkM3 · #15 04-02-2014, 09:16 PM

Quote:

Originally Posted by shertex

That's interesting...I noticed the same thing and wondered about it on a high mileage 91 300D that some guy recently showed me.

I have a couple of extra ALDAs if you'd like to go that route.

PM me with details please.
Thanks.

BTW, will try to update with actual photos soon, just no time past few days to do anything. Hope also to rig some sort of temporary boost gauge up.