Engine Problem

Thank you Norbert,

I myself i was a bit "shy" when i first got my 450 SE D jet, but i got over it, and i started to learn how it works.
Also, i am a mechanic for about 20 years, so that helped a bit.

About considering camshaft wear.. i would not discard for completely, because Juan ( Ola Juan didnt mention how many kilometers the car has. But, knowing Daimler Benz way of doing things, at leas back in the day : 1. Camshafts are forged, wich is a pretty tough process. 2. M116 and M117 were built to last for a lifespan of 4 milion kilometers.No one did 4 milion kilometers with an engine of this type. At least, not that i know of..

Gruss

Adi

Exactly what i was thinking and suggesting in here.

Another posibility, is that some" criminal hand" got to mess up with the rotor. Maybe prevoius owner.., mechanic.. As it did happend to my rotor, in my motor!..



Adi

Dear All,

Since the only part in my engine control that I did not change is the ECU I decided to check this part as well.
I attached the picture of the bottom of one of the boards. Since the size of the picture allowed is relatively small the picture quality is not good. However the brown spots are visible. I have cleaned one of the boards. I want to check the bottom board as well but I wanted to get your advice before continuing further. Do I have to unsolder the soldered cables to detach the bottom board?(presented in red semi circles-bottom board jpg )

rgds
juan

Hi,

it is correct that you have to remove all connections to resistors (which you marked red) plus the one to 4 power transistors and power diode befor you can remove lower board.

However I do not recommend you to do so.

Hi Volker,

I am not planning to repair the ECU myself.
As you may remember I have this engine problem which loses rpm on a specific throttle level and I have to push harder to accelerate and keep the engine rpm steady.
Members in the forum have already recommended checking the rpm limiter, camshaft wear. My mechanic is suspecting the injectors. I had them cleaned. During this process I have found out that four out of 8 are either performing under and over the limits. The rest are fine. I have obtained five new injectors from my spare part dealer which I keep aside for the moment. My mechanic also recommended to inspect the gas tank as he found some debris in the fuel line? ( I cannot understand this as the fuel filter was recently changed and I have driven the car only couple of hundred kms as the performance is lagging)
My mechanic also checked the engine with another ecu from 3,5 V8 and did not see any change in performance.
However I wanted to make sure that ECU is o.k., too since it is the only part that was not inspected.
It may not be visible in the images due to low resolution but the board was oxidized.
I suspect that the same is valid for the second board.
I am planning to examine the bottom board with an endoscope camera before I attempt something like this.
I read your articles about the ECU and fine tuning after repair.
However I am also helpless.
Can you recommend anyone who is specialized such repairs.
regards
juan

Hi Juan,

I do not know anyone in Turkey who could do such a repair. And customs from TR to DE and also back is a nightmare. Otherwise I would offer my help. Maybe you ask Bosch in Turkey if they can help.

I do ot believe in an ECU fault if you have already replaced it once. If your PCB boards are covered from water with a crust, then I can also give you no hope that it can be cleaned. I tried that once and that ECU continued to drift in ints values all the time, no matter how much I tried to clean it. In such a case I recommend replacing it.