Starved for fuel? Fuel very low in pre-filter - PeachParts Mercedes-Benz Forum

willrev · #1 02-09-2006, 08:31 PM

I was checking the oil while filling my tank with diesel today on the 82 300sd and I noticed that the clear plastic pre-filter before the IP had very little fuel in it and lots of air.

Is this a sign that my trap or filter in the tank is clogged? Pre-filter is usually full of fuel. I primed it with the hand pump and it filled back up. The tank was very low on fuel.

DieselAddict · #2 02-09-2006, 08:42 PM

99% sure it's a clogged fuel tank screen.

pawoSD · #3 02-09-2006, 08:43 PM

It could also be an air leak in the lines somewhere between the prefilter and tank, there's rubber lines back under the tank too, I'd check all the lines/their condition first.

willrev · #4 02-09-2006, 08:44 PM

Yeah. I just did a search and read the posts on the tank screens. I have never changed that one. I guess its time.

Just one question. Do I need to use a biocide? Would a full tank of B100 clean out the tank? I don't have access to any nearby, but could get to some about 2 hours away. Would a tank full of that clean out my strainer and kill anything growing in there or is the biocide better?

Diesel Giant · #5 02-09-2006, 08:51 PM

Your prefilter should not have any air in it or maybe just a little bubble at the top portion while running. The screen is not hard to do.

willrev · #6 02-09-2006, 08:56 PM

Appreciate the tip on the screen not being hard to do. It looks like a $19 part.

I think this is all starting to make sense. Yesterday, while driving at highway speeds, the car seemed starved for power. I was running with a low tank of fuel. It seemd to be running at a higher RPM.

After filling up today, it seemed to run better and have more power and run at a lower RPM.

this could also explain my lower fuel economy.

Just not sure about getting all the debris out of the tank.

Diesel Giant · #7 02-09-2006, 08:59 PM

Is the inline filter new?

Austin85 · #8 02-09-2006, 10:25 PM

1) If you're low on fuel, that may be a good reason to not have fuel in your clear filter. Make sense?

2) Get 2 sets of new primary and secondary fuel filters from Phil at Fastlane.
Keep spare set in the trunk.

3) Drain tank and clean your tank screen. Unless it's broken you don't buy a new one. It's meant to be cleaned. Acetone will work.

4) Buy a 12 oz bottle of Startron Diesel additive at WestMarine or other marine supply store, and use per directions.

(This should be copied and posted as a banner on the homepage of this site.)

DieselAddict · #9 02-10-2006, 03:27 AM

I can second the StarTron recommendation. However I would do that first before draining the tank and cleaning the screen. You may not even have to do that if StarTron manages to break up the sludge. I'm not sure if it will. But be ready for the other filters clogging and have spare ones nearby, especially the main, spin-on filter.

willrev · #10 02-10-2006, 09:47 AM

Yes, the pre filter and the spin on were just changed about 6000miles ago. It is probably time to change again.

I have a West Marine in Raleigh,NC about 45miles away. Will get my wife to pick some up since she works there.

Is it the star tron tank cleaner or the other star tron diesel additive?
Is this the right product?
http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&productId=234219

Thanks.
Will

DieselAddict · #11 02-10-2006, 12:52 PM

The Tank Cleaner is more powerful from what I've read and it may be more appropriate in your case. Either one will do though.

willrev · #12 02-15-2006, 08:29 AM

I am going to Raleigh today so I will get some of the tank cleaner. I am wondering if I should change the old style primer pump out to the new updated one. I might be getting air leaking into the system there. I noticed when the in line filter was full of air again yesterday at fill up that the primer pump would not pump it full again.

This may be more of the problem since I do have plenty of power going down the road. I had her speedometer pegged yesterday and running at 4300RPM down the interstate. It never hesistated a bit.

I am thinking I may have an air leak, not a plugged screen.

DieselAddict · #13 02-15-2006, 01:04 PM

I would change the primer pump, but I wouldn't rule out the tank screen, in fact my bet is still on the screen as the cause of your problem. My 240D had a plugged up tank screen as well and there was no symptom other than fuel starvation at idle when the fuel level in the tank was low. I did end up draining the tank and cleaning the screen manually.

Hatterasguy · #14 02-15-2006, 03:07 PM

It couldn't hurt to change the old pump, they are cheap and simple to swap out.

When I run my SD down to 3-4 gallons the fuel filter will go dry. I suspect the strainer is probably clogged a bit. I just don't run it down that low I don't feel like cleaning it.

Diesel Giant · #15 02-15-2006, 05:29 PM

Clean the strainer, keep the tank more than 1/2 full.