C16 RKC's Project 2003 CL500 (and other stragglers)

[c16rkc]

I'm in the process of changing the rocker cover gaskets on my M113K, found all the 20 year old rubber breather pipes to be in good condition and not perished so it's worth having a look before spending on them.

Thanks - I actually ordered all the breather pipes, and connectors earlier.... I should not have been so hasty

I also ordered the sealant and stainless bolts for the breather plates.

 

[91dm]

It won't do any harm! Mine could have been replaced at some stage, I was surprised they didn't fall apart in my hand.

Keep us updated on progress!

 

[c16rkc]

A very frustrating weekend

The good news first; my ABC pump arrived.



It actually arrived earlier in the week, and I had it fitted in no time. But sadly.. though Aston and Spencer enjoyed another play in the CL, it is still grounded on it's suspension!!!



I put in 1/4 of a tank of fuel so there was plenty to play with, and started her up. The engine purred beautifully... but despite my patient waiting... nothing!

I really struggled to believe that the pump was not working, so, following guidelines about changing a pump, I assumed it needed pressurising to force oil into it, and maybe there was air in it. So I pressurised the header tank with my air compressor... nothing!

Then I jacked the car up, and removed the Pulsation dampner, and the idea is you wait for air to escape, then the oil to start coming through. Oil started spraying out from the threads of the pulsation dampner straight away, so there is certainly some oil getting through.

So then I thought, have I got any pressure? - I consulted the Mercedes online ABC bible/blog (below link) and it stated this about the pressure sensor near the pulsation dampner: "At zero pressure the voltage is around 0.6 volts. At full pressure it is at 5 volts". So I decided to take a voltage reading at the senor, and see what I have.

Mercedes Benz ABC System Troubleshooting Guide

mercedes-abc-drive-carefully.blogspot.com

Now sadly there are three wires on the sensor, and I had no idea which was which. I assumed one would be "0V" one would be a permanent "5V" and the other would be the output signal voltage. I decided to go for it, and I hacked in so I could measure the different points.



There are three wires, Yellow, Blue, and Blue/Green. These are the readings I got:

Yellow to Blue = 4.96Vdc
Blue/Green to Blue = 4.36Vdc
Blue/Green to Yellow = 0.5Vdc



But this does not tell me much... because I don't really know what they all are. I am hoping I have found one permanent 5V signal, and the other is the system pressure; because if I have then the pump is at least doing it's job.

So I have purchased a Mercedes WIS copy, and it is currently downloading. I am hoping it will show the wiring for the ABC pressure sensor at the pulsation dampner. I can then determine which wires are the output voltage for pressure.

But regardless I think I am stumped, even if the pressure is good. I think next course of action is going to be for me to purchase a copy of STAR so I can read the codes of the ABC system and get some clues as to why the car will not raise.