Engine "knocking" noise- help? - PeachParts Mercedes-Benz Forum

jake12tech · #1 07-13-2017, 12:14 AM

Quote:

Originally Posted by Rogviler

Well, just as long as the canola is in the fuel. Diesel Purge is the same, the engine runs quiet while you've got it running through and people think it's fixed something but then the noise returns more often than not. Both are quieter because they burn easy, I guess.

The first time I dumped some old (but unused) cooking oil in my tank I thought the engine died when I was idling through a parking lot it was so quiet.

-Rog

It runs better off of diesel purge because of the higher levels of cetane than fuel. It's a more complete combustion and can mask bad injectors, or other related issues to fuel. It's great for diagnosing fuel issues. I'm not sure why oil combats better and makes the engine quieter. I'd assume lubricity properties.

@ the OP. Why did You remove the injector lines and not crack them just a quarter turn? Also, your next step should be to do the valve adjustment with feeler gauges.

Rogviler · #2 07-13-2017, 01:43 AM

Quote:

Originally Posted by jake12tech

It runs better off of diesel purge because of the higher levels of cetane than fuel. It's a more complete combustion and can mask bad injectors, or other related issues to fuel. It's great for diagnosing fuel issues.

Yes, but because it burns so well it also gives you the same "fix" if you have bad compression, incorrect timing, et cetera. So if it runs quieter no matter which you have I don't see how it's automatically a fuel problem. It could be any of those.

-Rog

jake12tech · #3 07-13-2017, 11:39 AM

Quote:

Originally Posted by Rogviler

Yes, but because it burns so well it also gives you the same "fix" if you have bad compression, incorrect timing, et cetera. So if it runs quieter no matter which you have I don't see how it's automatically a fuel problem. It could be any of those.

-Rog

I've never seen it correct compression. if compression is bad enough the purge wont mask it. Same with timing. It's mainly used to mask poor nozzles. I only say that cause I did it on my 92 300d before I swapped it and it didn't mask the low cylinder compression misfiring.

danielac · #4 07-13-2017, 11:23 AM

Quote:

Originally Posted by jake12tech

It runs better off of diesel purge because of the higher levels of cetane than fuel. It's a more complete combustion and can mask bad injectors, or other related issues to fuel. It's great for diagnosing fuel issues. I'm not sure why oil combats better and makes the engine quieter. I'd assume lubricity properties.

@ the OP. Why did You remove the injector lines and not crack them just a quarter turn? Also, your next step should be to do the valve adjustment with feeler gauges.

Mainly because I have no idea what I'm doing. I pulled the injector lines off all the way, which made me realize I need new lines. Going today to pick some up.

If I wanted to adjust the valves in the next day or two, are there any stores that sell the adjustment wrench or do I pretty much need to look online and wait for shipping?

jake12tech · #5 07-13-2017, 11:36 AM

Quote:

Originally Posted by danielac

Mainly because I have no idea what I'm doing. I pulled the injector lines off all the way, which made me realize I need new lines. Going today to pick some up.

If I wanted to adjust the valves in the next day or two, are there any stores that sell the adjustment wrench or do I pretty much need to look online and wait for shipping?

Order them online. Why do you say you need new lines? Are you talking about the metal hardlines? If you aren't sure of what you're doing, before you do anything, ask questions! Before you break or make a big mistake that could cost you the engine. Before you do tbe adjustment, do consult.

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