Overload protection - PeachParts Mercedes-Benz Forum

Mariano Roberto · #1 02-12-2009, 06:08 PM

Hello everyone, I'm Roberto from Spain, I and my car is german, 124,133 / 603,960 Mercedes 300D Turbo 1990. Excuse me, my english is very poor (Google translator help me) but I try to communicate with other living beings of the same species, especially with fans of this lovely hobby - german cars. I have a doubt with this:

What is this? If anyone knows please clarify my doubt and second is that because my car was going very slowly I removed the valve of overload protection and I regulated Alda. My car now is another very distinct quick response is much more than before, the automatic gerbox switches change much faster and thinner. My question is: Could this cause any negative effect on the engine and automatic gearbox? Thanks for the replies

compu_85 · #2 02-12-2009, 06:21 PM

This is a common problem with the over-boost protection solenoid, soot and oil from the intake manifold tend to block it up.

You can try using starting fluid to clean out the blockage (something that is mostly ether). Brake cleaner is too strong and my damage the plastic. You should fix the over boost protection system, it is a good safety net.

-Jason

Bizarre · #3 02-12-2009, 07:32 PM

I have a similar problem on my Mercedes Benz w124 300TDT 1988 with the 603.96 engine... my car is going really slow and after many hours of work on it i found out that the problem is the overload protection valve always is closed. that means no pressure to the alda = no boost.
i checked the turbo and everything and that seems to run perfectly. ive also checked the 2 small lines going in and out of the valve.
Ive also discovered that the valve needs electricity to shut and no electricity to be open, so ive tested the wires connected to it and discovered that it always gets electricity.

So my question is if anyone knows where the overload protection valve electric wires lead to? is there a relay or something that could be broken?

I also bypassed the valve and then everything worked fine. but i want to be on the safe side and have the protection just in case..

Oh and please forgive my bad english, not so good at writing it. Im actually from Sweden so...

Thankfull for any reply

babymog · #4 02-12-2009, 07:42 PM

I believe the electrical (pressure) sensor to be on the intake plenum / manifold. Further, I think that the valve gets +12v at all times, and the pressure sensor grounds the other wire, might be wrong.

Cr from Texas · #5 02-12-2009, 07:47 PM

Welcome to the forum Mariano Roberto and Bizzare. Your English is more than adequate as we all speak and write in Mercedes on this forum. I'm not familiar with your model but I know there are others that will soon help you with the problems.

Bizarre · #6 02-12-2009, 07:50 PM

Quote:

Originally Posted by babymog

I believe the electrical (pressure) sensor to be on the intake plenum / manifold. Further, I think that the valve gets +12v at all times, and the pressure sensor grounds the other wire, might be wrong.

Yeah ive located the pressure sensor. but havent had times to test it anything.

i do think you have a point there and i will test it first thing tomorrow.

Does the wires go directly from the valve to the sensor or is there a fuse or something between?

And thanks Cr from texas, ive read a lot on this forum before i made an account. hope to get some help and maybe help others with some problems as well

Mariano Roberto · #7 02-12-2009, 08:20 PM

Quote:

Originally Posted by Bizarre

Yeah ive located the pressure sensor. but havent had times to test it anything.

i do think you have a point there and i will test it first thing tomorrow.

Does the wires go directly from the valve to the sensor or is there a fuse or something between?

And thanks Cr from texas, ive read a lot on this forum before i made an account. hope to get some help and maybe help others with some problems as well

I checked the pressure sensor and it is OK , also the temperature sensor it is OK too ... something give 12V voltage to overboost and it stay closed all the time...??

Mariano Roberto · #8 02-12-2009, 08:24 PM

Anyone Know what kind of clima is in this picture:http://www.peachparts.com/shopforum/attachments/diesel-discussion/64237d1234479847-overload-protection-124-clima.jpg

LUVMBDiesels · #9 02-12-2009, 09:01 PM

Roberto and Bizarre welcome to the forum and the club.

I removed the overboost and the ALDA from my 300SDL. there are others on here who have done the same. There have been no cases of the engine running away and over boosting. After I removed the ALDA and the overboost the car accelorated much quicker and is much faster.

Roberto, if your transmission is not shifting at the right RPM, try adjusting the BOWDEN CABLE. It is the cable that runs from the accelerator linkage to the trasmission. If you loosen the nut at the top of the cable and lengthen the cable, the transmission will shift later at a higher engine RPM. The transmission should shift at around 3800~4000 RPM with the pedal all the way down.

Good Luck!

compress ignite · #10 02-13-2009, 01:20 AM

El Sensor eléctrico es # 137 en el esquema.

El Sensor Eléctrico de la Presión (solo alambre) rutas directamente al "Válvula de Protección de Overboost". Cuando algún otros lo han indicado puede llegar a ser "Atascado" con una mezcla de niebla de petróleo y mierda de EGR. O acaba de ser Malo. Al operar apropiadamente, "Motivo" el alambre que lleva al OPV, en una cierta Presión de Empujo.

Yo no hablo español
(freetranslation.com)

The electrical Sensor is # 137 in the diagram.

The Electrical Pressure Sensor (single wire) routes directly to the "Overboost Protection Valve".
As some others have stated it can become "Clogged" with a mixture of oil mist and EGR crap.
Or it can just be Bad.
When operating properly, it "Grounds" the wire leading to the OPV ,at a certain Boost Pressure.

compu_85 · #11 02-13-2009, 01:48 AM

Quote:

Originally Posted by Mariano Roberto

Anyone Know what kind of clima is in this picture:

No, I was going to ask you!

Mariano Roberto · #12 02-13-2009, 07:45 AM

another shot here with the same subject:

Bizarre · #13 02-13-2009, 10:27 AM

Ive replaced the pressure sensor with a new one, still no change. and i also have loaned a pressure valve from another 300 tdt and still no change.. the valve is "closed" even when the car isnt running, only have the electricity running..

Im guessing that the cable grounds somewhere else. but its not the pressure sensor that grounds it.. cause ive tried to disconnect the sensor and its still shut..

And also i must ask, there is 2 cables going in to the overcharge valve and only one going into the pressure sensor.. where does the other one lead?

--------------

compress ignite · #14 02-14-2009, 03:19 AM

El motor OPV ("El Otro Alambre")

Cuando usted puede ver lo es un POSITIVO/el PODER dirige que brincos a través de los componentes hasta que lo consiga es comida del fusible #7. Con el interruptor de
encendido en "Corre" o le "Comienza" siempre tendrá 12 voltios a la terminal #2 en Y30.

¿Dice usted que hay un circuito "Completo" en Y-30? Entonces algo proporciona un Suelo a la terminal #1 (Cuando usted desenchufa la S de sensor-66)

(La único diferencia verdadera en el '90-' 91 versión es el fusible #7 es 16 amperios en vez de 8 amperios)

As you can see it's a POSITIVE / POWER lead that skips across the components
until it gets it's feed from fuse #7.
With the ignition switch in "Run" or "Start" you will always have 12 volts to
terminal #2 on Y30.

Are you saying that there is a "Complete" circuit at Y-30 ?
Then something is providing a Ground to terminal #1 (When you unplug the
sensor S-66)

(The only real difference in the '90-'91 version is the fuse #7 is 16 amps instead of 8 amps)

EDIT:The OVP relay (K12/1) (Behind the plastic cover,behind the Battery)
is "PiggyBacked" off the (Negative) terminal post on S66...So if the Fuse
in the top of the OVP relay is bad OR the OVP itself is BAD...You could
get a "Ground" to Y 30.

¿Ha tratado usted al limpiar el motor OPV rociando Limpiador Eléctrico de Partes en los pezóns en caso de que hay alguna mierda adentro?

Have you tried cleaning out the engine OPV by spraying Electrical Parts Cleaner into the nipples in case there's some crap inside?

compress ignite · #15 02-14-2009, 04:05 AM

Hay una línea de PRESION de #138 (La Toma Múltiple, Que es presurizada por el Turbocargado) al ALDA #103 (Piensa en ello como un dispositivo de enriquecimiento de combustible para la Bomba de Inyección). Cuando el ALDA "VE" el
aumento de Presión de Empujo a través del pezón en # 138 permiten más combustible para fluir con lo cual aumentando el Poder.

Presión de #138 al ALDA#103...UNTIL que la Presión de Empujo alcanza 1,2 Barra, entonces S-66 (el sensor eléctrico de presión) Motivo la línea
Eléctrica que va a #103 completar el circuito. Y Y-30 entonces "Descargan" el Empujo, protegiendo el motor.

Así que usted ha conseguido un dos sistema de parte: Eléctrico y Presiona. AMBOS de que deben ser servible.

There is a PRESSURE line from #138 (The Intake Manifold,Which is pressurized
by the Turbocharger) to the ALDA #103 (Think of it as a fuel enrichment device for the Injection Pump).When the ALDA "SEES" the increase of Boost Pressure
via the nipple at # 138 it allows more fuel to flow thereby increasing Power.

Y-30 (the Engine Overload Protection valve) "Rides Herd" on the Pressure Line
from #138 to the ALDA#103...UNTIL the Boost Pressure reaches 1.2 Bar,then
S-66 (the electrical pressure sensor) Grounds the Electrical line going to #103 completing the circuit.
AND Y-30 then "Dumps" the Boost,protecting the engine.

So you've got a two part system: Electrical and Pressure. BOTH of which must
be in working order.