My First Cause for Concern - PeachParts Mercedes-Benz Forum

Joe Blowe · #1 10-16-2002, 07:46 PM

I've owned my wagon for almost 2 months now, and it's been troublefree since day one. But I guess something was bound to happen...

Went to start her up today (with the proper amount of glow plug time of course), and it turned over and sputtered a bit and then stopped. Did the glow plugs again, and it started fine. Okay.

Now, I'm driving towards my first stop, and as I approach the intersection it dies again. Start it up again, and this time it's running a little rough (similar to very low idle). Runs fine for a while, come to another stop sign and it dies again. Now I'm worried.

While this is happening, I happen to notice that my fuel needle is in reserve territory, but the light is not on. (At this point, I haven't put 2 + 2 together yet.) As I go on my way, the fuel light comes on, and now I notice it's running pretty hard. (Now the light goes on in my head!)

So I find the closest station (paid $1.53, btw, ouch) and fill up. And to my amazement, it's running fine now. How is this possible? The car came with brand new fuel filters, has been running great up to this point, and then I run a "little" low on fuel and it feels like it wants to fall apart...

Is the solution not to let it get below a 1/4 of a tank? Do I have an injection problem? If so, wouldn't I have noticed sooner?

psfred · #2 10-16-2002, 07:53 PM

More likely you have a goofy fuel gauge sender or a plugged tank screen -- as the fuel level goes down, the portion of the screen it can go through decreases, and if the bottom half or so is filthy, no fuel comes through.

Get the strainer in the tank cleaned. Meanwhile, consider the quarter tank mark empty. Don't run it completely out of fuel, takes forever to get it primed again!

Oh, and since this is a wagon, look for a dent in the fuel tank -- placed correctly, it will prevent the float from falling past the 1/4 tank mark......!

Peter

lrg · #3 10-16-2002, 09:23 PM

The reserve light in my wagon doesn't come on until I am well into the reserve. I'd suggest you use the gauge mostly. The light is for people who never look at the gauge, unlikely a problem for most everyone on this forum. When my tank gets really low I can sometimes get a small amount of air that causes the car to run rough. A little more air and the engine stalls and needs to reprimed. I agree with psfred that your strainer is probably partially clogged but otherwise I don't think you have to worry about going below 1/4 tank, just don't go too far into the reserve.

Joe Blowe · #4 10-16-2002, 09:33 PM

Well, that's two people who seem to believe it's my fuel tank.

So am I safe to assume that I properly pinned it on the tank, or could there be something more sinister at work here?

One thing I forgot to mention: after the first couple of stalls I realized that while approaching a stop, if I slipped it into neutral and gave it a "little more gas" I could keep it from stalling. Does this sound consistent with the diagnosis?

#5 10-16-2002, 09:54 PM

The only time I had problems with my fuel gauge is when I first got my 300CD. I added a can of Diesel Purge to the fuel tank on the first fill up, and the second fill up I added some Hi-Test. This seemed to clear up stuff and the gauge started to work. I havn't had any problems with it since.

84300DT · #6 10-17-2002, 07:36 AM

seems like your car was almost out of fuel.. duh..
1st thing i would do right away is change out the fuel filters (both)
as running the tank almost empty could churn up debris. cheap
insurance and a diy job.

i try not to let mine get too low especially in the winter- i rather use the trip odometer also as a fuel gauge to be doubly sure.

anhydrous7 · #7 10-17-2002, 03:51 PM

I agree with 84300DT. When you get too low, you will be more prone to pick up debris/dirt from the bottom of your fuel tank and also be more prone to pick up water. Water is heavier than fuel and will settle to the bottom. By letting your tank get that low, you were probably getting rough running from the water you were picking up. I try not to let the tank go below a 1/4.

You may want to let the tank get low again and pull the screen in the tank.

Joe Blowe · #8 10-17-2002, 07:42 PM

Well, everything went fine today. It's running smooth, and there's none of the sputtering that I experienced yesterday.

Now that I know I have to address that tank screen, would it be worth it to remove the tank completely and have it steam cleaned? There's almost 21 years of gunk sitting in there, so I would think now's the time to get rid of it, as I'm planning on driving it for at least another 21 years...

And while we're on the topic, does anyone here have any direct experience with Racor bypass filters? My friend's 300TD-T came equipped with one (hardcore previous owner), and there's a noticeable difference in the condition of the OEM fuel filters.

http://www.parker.com/parkersql/default.asp?type=2&id=27&g=h

billrok · #9 10-17-2002, 08:12 PM

I personally don't think you need to reinvent the wheel when it comes to the fuel system. I changed my pre-filter yesterday after 12,000 miles and after tearing the old one apart, it was like new inside with only a few small grains of dirt. The primary/secondary system the german engineers have come up with is all you need for another 20 years. If you use a good additive, your tank is really not all crudded up inside anyway. Take a look inside when you change the tank screen and you'll see.

#10 10-18-2002, 02:53 PM

Interestingly, my sdl does this when it gets real real low but still shows gas in the gauge...

Ken300D · #11 10-18-2002, 03:25 PM

I had a gasolene vehicle that sat outside waiting for repairs over the winter with about 1/4 tank of fuel. When I finally got it going again, it acted just as you describe when the fuel got down below 1/4 tank.

It was water accumulation. I don't know how much water, but it was enough to mix with the fuel sloshing as I drove along. A few good shots of alcohol-based fuel treatment took out all the water and it was fine.

A suggestion is to use a fuel additive specifically made for diesel fuel that will remove a few ounces of water each time you use it. Power Service additive will do this. If it really is water you should see an improvement over time.

Ken300D

leathermang · #12 10-19-2002, 12:01 PM

Joe Blowe, you think the way I do... I have taken half a dozen tanks off vehicles and really cleaned them up ... Always felt better about them afterwards...and found a lot of stuff inside some of them.... some were even starting to rust on the top outside.... I treated it just like it was the hood... some mechanic will see that and think someone was compulsive/obsessive....

.... but I know it will last another 20 years...Take pics if you do it for the FAQ pages , if they are still around... many people OUGHT to clean their 20+ year old tanks but don't tackle it.... if you do flush it... how about emptying it through cheesecloth for picture taking purposes.... some might be surprised at what you find....