SpannMan

Well, I finally purchased a 1998 E300 TD with 31,000 miles in wonderful condition. Over the weekend, I decided to fill the tank, since I was approaching a 1/4 tank. I added roughly 14 gallons, which brought the indicator to full. I assumed 3/4 of a 21 gallon tank would be roughly 15 gallons. I reset the odometer and recorded the purchase into my logbook.

I have driven roughly 200 miles and the indicator is already pointing to a half tank. I was expecting better milage. 10 gallons * 30 mpg should be closer to 300 miles at half tank.

I have read there are some known problems with a fuel level sensor. Could this be my problem and if so, how do I rectify? Is this something that can be done by someone with limited mechanical skills, or do I need to get a dealer / local shop involved?

I will know better once I refill the tank and measure the actual mpg, but I am nervous because I just purchased the vehicle and there is no warranty since it is past the 4 year mark.

Any hints will be appreciated.

SpannMan

paomien

Hi, I've had a few problems with my fuel gauge, only the problem was that I would fill up, and by the time I got to a half a tank, the needle would then drop to 0, and wouldn't come back up until I had less than 1/4 tank left. My stealership replaced the fuel sensor unit 4 times until it was corrected (plus one replacement up in toronto when i was up there, by a mercedes benz express service center...i wonder when they will open them here...it's an actual express center, no appt necessary, just walk in, first come first served, and they can do almost everything there...you can even walk into the bays and watch them work on your car)
Good luck!!

Lightman

on my '99 E300, I'm around 250 at the half tank mark , with fairly aggressive driving and a b20 biodiesel mix. This has dropped slightly since the addition of 18" wheels though..

SpannMan

I have been logging milage, gallons, mpg and where I purchased the fuel at every refil. I am convinced that my milage drops whenever I fill with B5 biodiesel. I think I have enough data to make this statement. My previous car was a chipped TDI and no matter where I refueled or how I drove, my milage never varied more than a few mgp. This E300 seems to prefer Amoco or other local blend more than the B5. It does, however, run much quieter on B5.

Lightman, have you chipped your E300?

SpannMan

Lightman

My e300 isn't chipped because the 606 engine already makes the torque limit for our transmissions. The 8 cylinder 430 and e55 e-class have beefier transmissions.

Biodiesel has 10-15% less btu's so mileage will drop slightly at a b20 mix. This of course depends on the quality of the petro diesel you're starting with, and the quality of the biodiesel. I use griffin's bio-g3000 which is a 53 cetane fuel. I usually buy it in 55 gallon drums, 3 at a time. I run 100% biodiesel in my chipped '02 tdi jetta, and 20% in the benz. My combined city/hwy mileage on the jetta with aggressive driving and b100 is between 44-46.

With all of the benefits biodiesel provides, losing 5-10% mpg isn't really too hard to swallow.

Spannmann, the brand of diesel fuel you choose in your area - unless its specifically a premium , such as Amoco Premier or BP diesel Supreme, will most likely not matter. It's all pretty much the same stuff coming from the same pipeline, and all distributed from the same terminal.

I'd recommend getting a diesel fuel test kit from www.avlube.com and testing your local station. I bought two, and found my local amoco to be absolutely HORRIBLE in dirtyness, and my local Texaco "premium diesel" to be extremely clean. Email if you'd like to see a copy of the test results...or i can post if anyone's really interested..

SpannMan

Lightman,

The normal diesel fuel I use is between 45 and 50 cetane, according to the person at the other end of the phone when I called the oil company. This same oil company is the same one supplying the BioDiesel. They blend with their normal diesel. I frequently use their B5 solution because the price is about the same as normal diesel and the pump is close to my house. They also offer B100 at another pump (15 miles from the house), but the price is $2.60 per gallon. I ran this B100 in my Jetta once. It was quiet and milage did not vary much.

BenzE

I had a problem with the fuel sensor as well, when my 2000 E430 4matic was brand new. They replaced the fuel sending unit and it has been fine ever since.

I have actually had a bunch of little problems like that with my car, and I attribute this to the fact my build date was 12/24/99. Who does good work on Christmas eve?!

Anyway, yeah, we need to lobby for the express service centers down here in the USA. Worth a trip to Canada! I think the NYC-metro area would be a prime candidate for such a place...

I'm in the market for a new job. Maybe I should open one?!

Lightman

Thats quite a rip off on the b100. I buy b100 between 1.60 and 1.80 for 53 cetane griffin bio-g3000 or occasionally world energy's biodiesel.

I wouldn't assume that the diesel you're buying is actually 45-50 cetane, i'd test it. More importantly than the cetane, is how clean/dirty it is. Particles in the range of 5-10 microns are responsible for wear on your injectors and fuel system. This is dependent on the fuel's handling and your particular station's cleanliness/filtration system.

SpannMan

I was disappointed when they finally began selling the B100. I personally lobbied the oil company to sell the B100 in our area. There was a big effort from a group of Fred's TDIers that live in the area. The oil company was responsive, but I only filled up once at $2.60 / gallon.

The 45-50 cetane statement was not an assumption. This was told to me by the oil company representative. Either way, I understand your point about testing. Perhaps I will give this a try. I assume that this testing is something which needs to be done often.

Lightman

Myself and others at freds have bombarded the different fuel companies regarding fuel quality, and believe me, there is no way to know unless you test, regardless of what you're told. I'll tell you one thing, if it's not marketed as a premium diesel, it sure as hell isn't near 50 cetane. Cetane improver is expensive, and your local diesel won't have that high of a cetane number unless it's either dosed with improver, or starts from premium basestocks and has a high natural cetane index.

For example, a friend from the tdiclub was told he was getting verified 50 cetane minimum Amoco premier. The station manager showed him receipts for purchasing premier as well as being confirmed by bp/amoco that premier was available in his area. After testing, it was found to be most definitely, NOT premier, at 46 cetane, and really dirty.

Like I said though, more importantly than cetane, is how dirty the fuel is. Fuel is given an ISO rating. The maximum allowed (dirtyest) ISO rating is 20/19/15. The amoco I tested near me had a cetane index of 43.05, and an iso rating of 22/20/15. The texaco near me had an ISO of 17/15/11, with the same cetane index. This is a huge difference. Lets compare in real numbers.
The amoco had 142,440,905 Particles bigger than 2 microns PER GALLON.
The texaco had 3,970,465 particles bigger than 2 microns.....

The bad part is that station owners/managers dont usually ever have a clue what cetane is, let alone ISO ratings.... they dont realize how bad this is for our injection systems, because most diesel customers(big trucks) have low pressure injection systems that aren't affected by such small particles. Most likely the amoco I tested has a microbial contamination. Despite this, it remains one of the busiest stations around, with a truck island, etc. Little do they know.....

Spann, when it comes down to it, if you really care about the longevity of your car and internals, get it tested, its the best $50 insurance you can buy to know what you're buying.

SpannMan

Lightman,

I appreciate the detailed answer about cetane and ISO. I cannot remember reading about the ISO number in the Fuels and Lubricants forum at Freds.

Regarding the testing, is this something which needs to be repeated on a regular basis? If I test the fuel from the station up the road and I determine the fuel meets my cetane and dirtyness requirements, will I have to test again? I would assume so.

Lightman

This fuel testing is a new thing over at freds, its only been available to us (through avlube.com) for a few weeks now. Some good news and some disturbing news has come since. We've had a few people test the fuel before and AFTER the fuel filter , and have found the factory fuel filter(which is bigger/more advanced than our E300's) is POOR at removing particles, and only works at about a 50% efficiency. If you saw some of the closeup pics of the injector wear due to these dirty fuels, you'd be concerned as well(or your wallet would be..). However, a CAT high efficiency and a Baldwin HE filter were tested, and both came in around 95% efficiency at the 5 micron level or so, both were great. Adapters and kits are being tooled right now for tdi's, i'm trying to figure out a way to get one on my E300, but we'll have to see how they turn out.

As far as testing multiple times...I'm not sure. I guess periodically you could test to make sure the station is maintaining its cleanliness. The cetane will stay about the same, and unless you're really making sure what you're buying IS 50 cetane minimum premium, who really cares, its low 40's crap #2, we already knew that.