Dirty Secondary Fuel Filter Photos - PeachParts Mercedes-Benz Forum

stephenson · #1 09-13-2006, 10:29 PM

So, had noticed performance dropping off - not so much top end, but accelerating. RPM max flat road was decreasing - got to where it would not even run up past 4000 RPM - starting considering usual suspects, including ALDA, turbocharger, etc.

0-60 time was, I swear, over 20 seconds .... maybe closer to 30!

gsxr and I discussed a few emails worth - I interconnected the two pressure lines going to the switchover valve - I got surging which surprise gsxr - I didn't know what to expect. So, started thinking about it and thought would replace the fuel filter.

After changing filter (had previously changed the inline filter), my rough watch timing says more like about 12-13 seconds or so - a clearly noticeable increase, plus the RPM would roll right through 4000 to nearly 4400 and then shift quickly and firmly - I could get it to shift a bit earlier (603.970 doesn't have much power way up) ...

I drained the old filter - it was very nearly black ... could see particles in solution - see container in background of photoe. I then chiseled open the filter to examine the paper element - it too was black (see second photo) - like you had poured old diesel crankcase oil on it ... grainy feeling, too.

I have never pulled the fuel straiiner in the tank - I got an oring from Phil so will probably do that sometime when I get down to fumes in the tank ...

With gsxr's email guidance am gonna hook up a Mityvac gauge and see what boost pressure am getting ...

Thanks, gsxr and all the other great knowledgeable folks on this site - dear god, I love getting oily and greasy!

pawoSD · #2 09-13-2006, 10:37 PM

Here's mine after about 20k....it was filthy as well, I noticed a slight power increase with the new one in....and I think it may be time to change it again....

stephenson · #3 09-13-2006, 10:40 PM

pawoSD - your's looks almost new!

You can see through the fuel, even ...

Hmmm - maybe I haven't changed the filter ... er, ever ... I swear, I thought I did!

Matt L · #4 09-13-2006, 11:44 PM

Nice dremmel tool there. You do know that you can buy an oil-filter opener, right? They're cheap, would work on the fuel filter, and wouldn't leave any extra metal inside.

pawoSD · #5 09-13-2006, 11:56 PM

Quote:

Originally Posted by Matt L

Nice dremmel tool there. You do know that you can buy an oil-filter opener, right? They're cheap, would work on the fuel filter, and wouldn't leave any extra metal inside.

Actually that dremel is now deceased

....but now I have a new variable speed one!

Matt L · #6 09-14-2006, 10:13 AM

Quote:

Originally Posted by pawoSD

Actually that dremel is now deceased

....but now I have a new variable speed one!

Dremel's aren't too bad, but after using an air-powered die grinder, I'm not looking back. They don't heat up.

stephenson · #7 09-14-2006, 11:21 AM

No supportive comments regarding my elegant chisel approach?

Matt L · #8 09-14-2006, 01:29 PM

Quote:

Originally Posted by stephenson

No supportive comments regarding my elegant chisel approach?

Well, there would be fewer fragments inside the filter than you'd get with a dremel.

If you're opening oil filters, it's not a good thing to be adding metal. The chance of finding fragments in the fuel filter would seem to be a lot lower, but still, you might want to know if they were deposited there by something.

gatorblue92 · #9 09-14-2006, 03:21 PM

the amount of dirt in those filters is impressive.. and not in a good way

although i doubt mine would look much different

F18 · #10 09-14-2006, 04:12 PM

Quote:

Originally Posted by gatorblue92

the amount of dirt in those filters is impressive.. and not in a good way

although i doubt mine would look much different

This is a stupid question....but does anyone know why or how diesel fuel gets so contaminated with junk? I have never opened a filter up but I think I will start with my next yearly fuel filter change.
I see some of the diesel fuel station pumps with their own spin on fuel filters and from my understanding they all have them externally or inside the pump housing....the fuel is filtered when its dispensed...so where does the contamination come from? Is it organic/bacteria/fungus growth in your tank?

I had a gas tank rust from the inside out once.. so could it be iron oxide/rust contamination?

sixto · #11 09-14-2006, 05:12 PM

Good question particularly when the smaller filter looks clean.

Sixto
93 300SD

bill murrow · #12 09-14-2006, 07:10 PM

Quote:

Originally Posted by F18

This is a stupid question....but does anyone know why or how diesel fuel gets so contaminated with junk? I have never opened a filter up but I think I will start with my next yearly fuel filter change.
I see some of the diesel fuel station pumps with their own spin on fuel filters and from my understanding they all have them externally or inside the pump housing....the fuel is filtered when its dispensed...so where does the contamination come from? Is it organic/bacteria/fungus growth in your tank?

I had a gas tank rust from the inside out once.. so could it be iron oxide/rust contamination?

This is a very good question.

My take is that it must be gunk in our tanks from years of use. Whenever I've gotten fuel and put it into a container it always looks clear with no junk floating around. Yes, the pumps do have filters on them. Ever notice how some pumps are slow? Thats the pump filter clogging up. To me that means the pump filter is doing its job.

A car that sits for extended periods will get gunk buildup in the tank/fuel system. Anyone know is this from the fuel evaproating or what? Could be fungus growing too I guess.

Cheers,

Bill

F18 · #13 09-14-2006, 08:34 PM

Here is a thought.....look at thoughs pictures that George and PawoSD posted again. The filters look like they are contaminated with particulate soot!
Is it possible that the soot is somehow picked up by the return fuel lines/jumpers from the injectors and soot contaminated fuel sent back to the tank?

raMBow · #14 09-14-2006, 08:50 PM

Quote:

Originally Posted by bill murrow

This is a very good question.

My take is that it must be gunk in our tanks from years of use. Whenever I've gotten fuel and put it into a container it always looks clear with no junk floating around. Yes, the pumps do have filters on them. Ever notice how some pumps are slow? Thats the pump filter clogging up. To me that means the pump filter is doing its job.

A car that sits for extended periods will get gunk buildup in the tank/fuel system. Anyone know is this from the fuel evaproating or what? Could be fungus growing too I guess.

Cheers,

Bill

Well I had changed my filters on the W210 a few weeks ago, after 3yrs and 15,000 miles. So you forced me to cut mine open. Pre-filter was pristine, spin-on filter looked the same on the inside as the pictures, black like 600 grit wet sanding paper. I presumed mine would be clean as I am very particular as to where I fuel. If I go on longer trips I bring 15-20 gallons of fuel with me so I can complete my trip without using questionable sources. So I don't think it is age related. Anybody change @ 10,000 and looked?

Sounds like we should just go change them annually?

John H · #15 10-06-2006, 01:08 AM

Quote:

Originally Posted by F18

Here is a thought.....look at thoughs pictures that George and PawoSD posted again. The filters look like they are contaminated with particulate soot!
Is it possible that the soot is somehow picked up by the return fuel lines/jumpers from the injectors and soot contaminated fuel sent back to the tank?

The black particles are bacteria and/or mold. As odd as it seems, organisms can live in the water droplets in the diesel. While I do not have a diesel in my Benz, I do have one in my sailboat (48hp woo hoo!). I add a biocide on a regular basis and change both fuel filters every few months.

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