EDS Codes on 1992 300D 2,5 Turbo - Page 2 - PeachParts Mercedes-Benz Forum

2.5Turbo · #16 03-30-2007, 05:21 PM

Quote:

Originally Posted by BigBen

The attached picture here is the Y31/5 Vacuum transducer, showing indeed 3 hose lines.

The top ones are identified as VAC and OUT. I would imagine the bottom one is linked to a vent line openned to atmosphere?

If I block the OUT port and apply vacuum on the VAC one, I get a "leaking" symptom,I won't be able to build a constant vacuum! Even with the new ones!!! So may be they weren't bad after all!

Anyways.

The important stuff is here:

Am I right by saying the Transducers (y31) translates or converts vacuum to a voltage signal fed into the EDS computer and that, according to preset conditions, the Switchover valves (Y27) then open or close by a signal received from EDS computer?

It would seem logical to me!

Let's see how the pictures show on this reply (1st test!).

Bye

Interesting. Maybe the transducers got changed between 91 and 92. Mine have four ports. The VAC and OUT, from vacuum supply and out to wastegate actuator respectively, and two ATM ports which are Y-ed together to a vent line to the passenger compartment.

With the OUT port plugged, you shouldn't be leaking any vacuum. Check all your lines...and if you have a mityvac, do some vacuum checks to pin down a potential leak in a line.

On the system's operation, the reverse is true about the transducers. The EDS sends a voltage to them, which I believe varies to control the amount of vacuum sent to the wastegate. The more voltage, the more vacuum, and the more closed it becomes which equates to more boost. The EDS knows the boost pressure from a pressure sensor located behind the battery (at least on my '90). It converts the boost pressure into an electrical signal the EDS can use. It monitors that boost signal and opens/closes the switchover valves and varies the wastegate to follow a set of parameters in its memory.

In your photo it looks like you have the wastegate actuator's line hooked to the ATM vent port.

BigBen · #17 04-01-2007, 11:11 AM

I did a few test runs 0-60 in the past couple of days.

I'm in the 16-17 sec range. I'm sure it can be better since I clearly notice a drop in boost under some circumstances. BUt don't get me wrong: this is already a major improvement over previous conditions (20+ sec).

But I will drive the car in real life conditions to become more familiar with its behavior and I will come back.

On another topic: I can confirm the Search feature here returns very valuable infos, it's a tool worth learning how to use (especially the Advanced Search options).

Bye,

BigBen · #18 04-01-2007, 09:18 PM

Quote:

Originally Posted by BigBen

In the order they appeared about in March 06:

15
8 B11/4 Coolant sensor
9 B2/1a Intake air temp.
2 L7 Fuel rack sensor
3 B2/1 Air flow sensor
11
5

Could anyone help with 15, 11 and 5?

And here are the readings today 1 April '07, after changing both vacuum transducers and Intake Flap actuator:

5
15 Y31/5 boost failure, vacuum transducer. I found this description in post #20 here: '93 300D 2.5T, 0-62 in 20 sec???

9 B2/1a Intake air temp.
2 L7 Fuel rack sensor
3 B2/1 Air flow sensor
11

I will search again to find out what 5, 15 and 11 mean and will edit this post to complete it.

I am thinking it could be an electrical problem with connectors or ground somewhere.

Any thoughts?

Bye

BigBen · #19 04-01-2007, 11:10 PM

Well, I just went out again for a test drive, and the car really hauls well now compared to its previous naturally aspirated state!

The boost does kick in soon near 1500rpm and quickly spikes to 13-14psi. Then it drops suddenly to around 10 psi (looks like the wastegate dumps exhaust gases directly in the muffler) and increases again.

So I went on the motorway for another test drive. There, I saw that boost ALWAYS drops around 5-7 psi (and holding there steady) with any RPM greater than 3500. But I repeat it still hauls very well compared to its prior state!

BUT, should it maintain 13-14 psi all the way to 4000 or 4500 rpm? In that case, it would be like a rocket!!!

Can't wait to hear comments.

Bye

BigBen · #20 06-06-2007, 09:53 PM

I read my codes once more tonight.

I am down to 9, 3 and 11. But I cannot clear them at all.

I have got some dielectric grease last week, so I'll try that next.

And then investigate cable route to the EDS computer to make sure I haven't got anything damaged (I know the Right Hand Side fender has been changed at some point).

Bye,

pmari · #21 06-06-2007, 11:07 PM

ELECTRONIC DIESEL SYSTEM (EDS)
Model Model Year
124.128 1990-93
126.134 126.135 1990-91
140.134 1992-93
FAULT CODE TABLE
DTC Readout Possible Cause of Failure
1 No fault found
2 Fuel rack position sensor (L7)
3 Air flow sensor signal (B2/1)
4 Electronic diesel system (EDS) control unit (N39) or atmospheric pressure sensor
5 Exhaust gas recirculation (EGR) valve vacuum transducer (Y31/1) or fault in exhaust gas recirculation
(EGR) control circuit
6 Electronic diesel system (EDS) control unit (N39), internal voltage supply
7 Starter ring gear speed sensor (L3)
8 Engine coolant temperature sensor (B11/4)
9 Intake air temperature sensor (B2/1a)
10 Voltage supply insufficient
11 Electronic idle speed control actuator (Y22) or exhaust gas recirculation (EGR) valve vacuum transducer
(Y31/1) or Boost pressure cut-out switchover valve
12 Not used
13 Electronic diesel system control unit (N39), faulty (internal fault memory)
14 Electronic diesel system pressure sensor (B5/1), defective
15 Boost pressure control/ pressure control flap vacuum transducer (Y31/5) , or defect in Boost pressure
control circuit.
Or
Intake manifold air pressure control valve vacuum transducer (Y31/2), wastage vacuum transducer
(Y31/3), or malfunction Intake manifold air pressure circuit

pmari · #22 06-06-2007, 11:11 PM

http://tech-meister.com/DieselBenz/TECH/300d-2.5l-tech-info.txt

Sun Jan 16 11:05:02 2005
From: Flash

Here's a guy from Hooterville, WI - Jim's neighborhood who tweaked his 300D
2.5 and has gotten rave reviews (he raves) about the performance. These may
be understandable tweaks, and something John with his 2.5 and others here
with 2.5 may want to try? Let us know what happens, if/when, john,
others...
DanG ChicagoArea
====================
I've decided to go into great detail of what I did to the 2.5. The white
2.5 had a blown head gasket when I got the car. It contaminated a number of
vacuum items, which is why I started bypassing stuff.

1) Overboost protection canister. Small one on the driver's side firewall.
Had soot in it, and prevented the ALDA from sensing pressure. Bypassed. I
don't think that I've had ONE of these work correctly on any turbo. They
all get sooted up eventually.

2) EGR. Also full of soot. I have a good replacement, but haven't gotten
around to replacing it. An EGR on a diesel is a dumb idea anyways because
feeding soot back into the intake is not good for it. Bypass is easy. Keep
the electrical connections intact to the vacuum pod. The signal to open and
close will be there, and the computer will be happy. Disconnecting the
vacuum lines and bypassing is all that needs to be done.

3) Turbo wastegate vacuum pod. The wastegate has a vacuum failsafe that is
normally open with zero vacuum. Bypass is to connect the wastegate vacuum
(which is the electrical/vacuum pod closest to the passenger side headlight,
low in the inner front fender), and hook it directly to the main vacuum
system. My wastegate vacuum pod leaks, and I need to replace it. Bypassing
is only temporary, as that particular failsafe is not good to ignore for too
long. The key to preserving the computer happiness is not disconnecting the
electrical harness to the vacuum pod.

4) Secondary turbo fault sensor. If something is very flaked up with the
computer or sensors, the secondary sensor which is mounted by the battery,
opens to kill boost pressure to the ALDA. Bypass is easy for troubleshootin
g. The only reason why you would want to bypass this for any reason is to
find other faults.

My point is that the highly sophisticated computer controlled turbo system
can be made very simple. Call it emergency road repair 101. If you have a
full time vacuum direct connect to the turbo wastegate, you'll have turbo.
If you have a single pressure line from the intake manifold to the ALDA,
you'll have appropriate fuel enrichment. Leaving electrical items attached
to the vacuum pods keeps the computer happy and compliant.

BigBen · #23 06-08-2007, 01:22 PM

Quote:

Originally Posted by pmari

FAULT CODE TABLE
3 Air flow sensor signal (B2/1)
11 Electronic idle speed control actuator (Y22) or exhaust gas recirculation (Y31/1) or Boost pressure cut-out switchover valve

Thanks PMARI,

It's 3 and 11 that got me worried the most. But I would very much like it to run as it was when new. After that, I'll probably mess around and change things.

For now, this 92 is going in my garage for a WVO 2-tank system transplant (I took the system out of my VW before selling it).

I need to save $$ to fix the electronics! I have some 200 gal (imperial!!!) sitting in 45 gal drums... and the supplier keeps making fries!

I'll come back to the electrics later on.

Bye,

pmari · #24 06-08-2007, 01:52 PM

BigBen · #25 06-08-2007, 02:26 PM

I have previously removed the MAF.

I played with the inside door or flap and tried to measure resistance from the connectors. I didn't get anything too consistent. It reacted as if a potentiometer had a "flat spot" in it. If it ends up being a costly repair, I will be crazy enough to tear it apart and try to make it work by changing the faulty component within the MAF.

I have fixed an electronic hitch control on our farm tractor last fall. CaseIH wanted 650$ for the assembly. Ended up costing 10$ (and 7$ in freight charges!) for a 3/4 turn, 0-10kOhm Pot from DigiKey. And it is still working.

If I resolve it like this, I'll certainly post my findings here.

Thanks again,

Bye

pmari · #26 06-08-2007, 02:31 PM

For more info go to http://s37.photobucket.com/albums/e93/pmari/

Let us know if you can use the values without the socket box and connector cables?

pdrayton · #27 06-09-2007, 11:15 PM

Pmari, thanks for the posts of the FSM procedures, but how do you test B2/1 without the hookup box thingy? I have measured 500Ohm across two of the connectors of the air flow sensor.

BUt I don't think the air flow sensor B2/1 is the problem with my car - I think it is a symptom. I replaced the shut off valve today, and in the process, removed the L7 idle sensor and ALDA unit. I adjusted the ALDA unit.

After I did all this, the car wouldn't sit at idle, it would die. I put some dielectric in the L7 connectors, and that problem went away. Now the only symptoms I have are idle drops to 500 and then recovers to 700 after revving up. Also, there is NO boost, turbo not working, and EDS error 3 - which is air flow sensor. I don't think the air flow sensor is the problem - I think it is just acting like it is buggered becuase something like the boost pressure sensor or something is not working properly.

This is not meant to be a hijack, just throwing in my experience in case there are common threads that set off some light bulbs, or maybe some one has a simple suggestion of what to check with mine. There is vacuum going to the wastegate valve at idle 15mmHg, drops to 0 at high revs. Seems backwards, but maybe that is how it is supposed to be.

BigBen · #28 06-11-2007, 09:18 AM

Thanks for your inputs pmari and pdrayton.

I too think I may only have a bad component elsewhere which returns a code 3 and 11. I don't consider this computer to be so advanced that it tells an absolute truth.

It's probably more that the set of data fed in the computer doesn't match a preset data put in memory. It then tells us that the data "seen" doesn't match for sensors x and y (3,9, 11, in my case).

I know I may be repeating myself here, but I have recently found that I had a leaking EGR valve, an unknown status for the wastegate actuator, etc...

So, I will do my homeworks and come back a little later.

Bye,

James L · #29 06-11-2007, 03:50 PM

I feel your pain, Going on two months and I am still troubleshooting my 5, 15 fault codes, I am getting weird volt readings. I wonder if you need to clear the fault codes before you test/troubleshoot to get good values?

My Y27/4 is the only valve that is up to spec (vacuum and volts), the y27 and Y27/5 are not acting right vacuum wise nor voltage wise. can these be tested individually with mityvac and ohm tester?

This EDS is a bear!!!

pdrayton · #30 06-11-2007, 09:22 PM

Like I said before, my 5 code was a genuinely buggered vac transducer on the EGR. Replaced it and things worked fine.

The 3 code I got this weekend was total BS from the eDS computer. So, yes, don't always believe it. My EDS 3 code (air sensor) was acutally becuase I had the engine stop vacuum valve in wrong and it was killing the throttle. What that has to do with the air sensor I don't know.

May the teutonic mercedes gods smile apon you and deliver the reparations required....