X164 2007 airmatic suspension system

[tony jr]

Since changing my airmatic suspension compressor my engine (OM642) has stopped running! I assume this is just a coincidence but you never know. The engine now starts, runs for 30 seconds before the engine shuts off. Can anyone think of a link between the two that might explain what’s happening. I can’t hear the new compressor working but I assume I need the engine running first.


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[Botus]

my genuine one's far nosier than the old one, it only operates for 10 second before taking a tea break then comes back on if it needs to

if you have a tractor heaven knows why you expect to hear it, it could be the new one works and the old one didn't so ran for longer

you should fit a new relay when you fit a pump, they age

if you park on a level surface and have no air leaks it should need to run often,

 

[tony jr]

I did attempt to change the relay at the same time and that may or may not have complicated things. I purchased a relay from a well known high street store. I took my old relay with me and asked for a direct replacement. The assistant checked both the old and the new relay and said they were compatible. I took it home, the pins had the same numbering and the same orientation. I put the relay in and went to start my car and that’s when my problems started. The engine started then switched off after 30 seconds. I removed the relay and checked the circuit diagram and the switching was the same but the position of the diode was different. I can’t see any reason why this would cause a problem with the engine. The circuits are completely different. I don’t have any problems that I can tell with anything else electrical. Hence my original question. Now I need to fix my engine to see if the compressor works.


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[Botus]

I think electrical systems on modern cars are odd, so much seems to interlink and or argue with each other, throw a bit of age, water and wear and tear in to a Merc and you soon need a very experience guy with the official star diagnostics gear to make sense of anything

relay from high street? there's only closed shops in a high street (unless u want women's clothing, a phone or a coffee)

there's a massive orange 40 amp fuse as well, is that OK

 

[tony jr]

The 40 amp fuse had blown when the old compressor went which was one reason for wanting to change the relay in the first place. I have had the old relay checked out and it still works fine


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[Botus]

don't doubt it works, but not as well as it should.... I was informed 2 years warranty not covered unless new relay goes in with the new pump

 

[tony jr]

Latest update: someone has been out to look at the car. He connected his laptop and cleared all the codes, including a timeout code for the suspension compressor. He started the engine and it ran as normal. He was able to control the suspension height with the laptop and everything appeared to work until he disconnected the laptop and the engine stopped as before. Any thoughts on what the problem is?

I forgot to say that when I restarted the car it ran for 30 seconds then stopped again as before. The suspension compressor did not turn on either.


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