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-   -   Slight idle vibration (intermittent) (https://www.benzworld.org/forums/w220-s-class/3017794-slight-idle-vibration-intermittent.html)

oliverp 02-13-2019 04:03 PM

Slight idle vibration (intermittent)
 
Hi Everyone

Ever since I bought the car a year ago, I have had an issue with an intermittent vibration. Sometimes it's when the engine is cold (I can feel it through the seat, and the door shakes if it's open - this is even in Park). Sometimes it's when the engine is warm at a stop light. Shifting from D to N seems to reduce it a bit. Sometimes it doesn't happen at all for days at a time. It doesn't correlate to engine or ambient temperature.

Initially I was going to replace the engine and trans mounts but the mechanic says they look fine and are fairly new. Also, with it being intermittent, I didn't think it could be the mounts. If they were bad I would expect it to be more constant.

On Friday I am replacing the spark plugs, spark plug wires, air filter and I am also getting the mass air flow sensor and throttle body cleaned.

I was wondering if anyone can think of any other maintenance activities to do while I am at it? I have a new CPS that I keep in the trunk just in case but I wasn't sure if I should fit this until I need to. I have SDS and there are no errors or codes. I am hoping that it's an issue with the plugs or wires that isn't serious enough to generate a code, but is serious enough for me to feel it.

Thanks
Ollie

(2004 S500 4Matic, 190,000Km, Toronto, Canada)

wallyp 02-13-2019 06:44 PM

Get about four feet of 1/4" - 3/8" rubber or plastic hose. Stick one end in your best ear, then use the other end as a probe to listen for the hiss of a vacuum leak. Go all over the top of the engine, and around the engine compartment. Be very careful to avoid moving parts and hot parts! You can tape the probe end of the hose to a wooden dowel or similar tool to make it a little easier to manipulate the probe into tight spots.

oliverp 02-14-2019 09:26 AM

Thanks Wally, I will check this out tomorrow and report back!

oliverp 02-16-2019 06:46 AM

The mechanic replaced the spark plugs, and also did the smoke test for vacuum leaks (he could not find any). He also checked 'fuel trim' which was normal.
On the drive home it was fine, but it's intermittent so I am not saying it's fixed yet.

I will reply again once I have used it for a few weeks.

Oh, and the valve covers are leaking a bit. We have cleaned it up and I will monitor to see how bad the leak is. So next job will be valve cover seals.

Funny that on the way to the mechanic my seat base would move back, but not forwards. On the way back from the mechanic it was fine. I put it down to lack of use. I will check the door control module with SDS later.

Thanks again
Oliver

4DGeorge 02-24-2019 09:15 PM

If you've not had the fuel system flushed, try a serving of BG's 44K fuel cleaner. When I bought my '06 S500 year ago, it would occasionally miss during cold starts and when idling. After two tank refills using BG's 44K mine began running a lot smoother.
I went several tank refills without using it and it began running a little rough again. Now I use it every third or fourth fill up to keep it running smooth.
I've been a fan of their products since 1988!
https://www.bgprod.com/catalog/gasol.../#bg-product-3

doni01 02-25-2019 11:59 AM

Quote:

Originally Posted by 4DGeorge (Post 17707102)
If you've not had the fuel system flushed, try a serving of BG's 44K fuel cleaner. When I bought my '06 S500 year ago, it would occasionally miss during cold starts and when idling. After two tank refills using BG's 44K mine began running a lot smoother.
I went several tank refills without using it and it began running a little rough again. Now I use it every third or fourth fill up to keep it running smooth.
I've been a fan of their products since 1988!
https://www.bgprod.com/catalog/gasol.../#bg-product-3

^^ Agreed :thumbsup: Great products and I use them often as well.

oliverp 02-25-2019 12:58 PM

Hi everyone
I actually bought a can of BG 44K last year but left it on the shelf for some reason - I think I read it was a bit harsh. I ran some techron through the fuel tank and I only every use the Shell Nitro+ fuel.
I will try BG44K before the next big drive. Am I right in thinking it's best to do an oil change after use?
Thanks
Ollie

doni01 02-25-2019 06:12 PM

Quote:

Originally Posted by oliverp (Post 17707576)
Hi everyone
I actually bought a can of BG 44K last year but left it on the shelf for some reason - I think I read it was a bit harsh. I ran some techron through the fuel tank and I only every use the Shell Nitro+ fuel.
I will try BG44K before the next big drive. Am I right in thinking it's best to do an oil change after use?
Thanks
Ollie

Yes they do recommend changing the oil after running the BG 44K. I personally sometimes do if I am close to an oil change but if I am not close for an oil change, I don't bother changing it.

wallyp 02-26-2019 04:53 AM

The best way to use a fuel system cleaner is during normal short-trip driving, not on a long road trip. You get much more cleaning effect by repeated heating/soaking cycles than from just running it through on a long trip.

doni01 02-26-2019 04:56 AM

Quote:

Originally Posted by wallyp (Post 17708162)
The best way to use a fuel system cleaner is during normal short-trip driving, not on a long road trip. You get much more cleaning effect by repeated heating/soaking cycles than from just running it through on a long trip.

^^ Great point!


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