Almost out of fuel??
 

Twice now I have been driving along with the gage just getting to the reserve and the car starts to surge after cornering to the right. once the road streightens out, it will lunge forward again.. so I pull into the nearest fuel spot, and put 14.7, (the first time) and 15.0 gallons of fuel in My 300 TD. The manual says that the fuel tank takes 21 gallons, with a 2 gallon reserve. (althoug my owners manual is not for a TD, but a 240/300D.) Do I only get a 15 gallon tank? Or do I have a plugged screen in the tank?
Jason

Are you sure it says 21 gallons for a w123 sedan? My 1985 300D manual says 14.7 gallons i think and a 2 gallon or so reserve... which makes sense cause i was driving on the reserve tank for a while and just filled up with 16 gallons.

W123's have small tanks! I have 23.5 gallon capacity and the light is supposed to come on after 20 is burned off. But I never run it that low, I usually only run it so I have to add 19-17 gallons.

How are you filling up? When I let the pump shutoff and then I ease gas into the tank till I can see it at the filler mouth, the difference is about 3 gals

I remember the W123 having a total capacity of 21.7 IIRC.

But, I also remember running out of fuel and putting 18 gallons in it to fill it completely. :eek:

I'll have to double check my manual..for some reason I really remember 14 something gallons.

According to this:
http://skinnerbox.steaky.org/Service/W123/w123CD2/Program/OM/OM-86.pdf
21.1 gals including a reserve of 2.8 gals.
Owner's Manual - 1985 Chassis 123D

You all are right... i checked and it was 21 gallons... that means im getting horrible fuel efficiency... like 16 mpg... gee and i thought i was getting a good 25 :rolleyes: Don't know where I got 14 gallons from, sorry for any confusion.

I still don't get why the reserve tank would come up so early though... i should have still had like 5 gallons left when I refilled today...the trip odometer was at 351 miles.

Ara, did you let the pump shut off or did you fill it till you could see fuel? For me there is anywheres from 2-3 gal of difference. More if it is a very fast flowing pump. Without that method, how will you find out how much fuel you put in? Sure, you have the distance travelled but your fuel consumption is not going to be a constant. I have got close to tank capacity using the fill to the neck method. How are your tire pressures?

I did it till the fuel pump shut off, our shop teacher always said that any more just sends fuel where it doesn't even get used and is a waste, money and pollution wise. I run 40 psi on all 4 tires, but I have not checked them for a month or so.

And where would that be? the problem with a diesel is that if foams a lot. I think your shop teacher was thinking of http://www.epa.gov/donttopoff/ when he said it. It doesn't bother me because:

1. The pump nozzle after shutoff is withdrawn till it is about 3 - 4 inches into the neck and I can see it. It will not feedback into the tanks although I have never seen a system that will if you do it like that.

2. I am careful with the filling so there is no spill issue

3. We are dealing with diesel so there is hardly any vapor, if any at all.

4. See #1

That is a little high or is that the spec for that vehicle?

I knew about the foaming issue so I fill up real slowly, but just until the fuel pump shuts off. I guess I'll fill up till I see fuel next time. As for tire pressures, I just went by my tire max pressure specs, which were above 40, though I dont remember the exact number. I found the tire pressure specs on the fuel fillup door too soft for me.

W123 300D/300CD - 21.1 gal.
W123 300TD - 11.5 gal.

Another possibility is that the fuel supply and return fuel lines have been swapped over (I did this to SWMBO's 300D due to fuel starvation problems). The car is normal for 3/4 tank but starts sucking air below 1/4 tank.
Swap over the fuel lines in the engine bay (Cigar hose goes to top pipe IIRC) See if it makes a difference.

I put the pump to the first setting and let it fill up till it shuts off. Then I play with the trigger to get more till I can see the fuel. That way it is consistant with the next time. You see, consistancy is the key here.

As to your tire pressure, I would go off what the card says and not exceed it or you might get abnormal wear on the tires. I did that before and wore out my tires prematurely. Also, when you do that, rolling resistance decreases so it might mask a problem you are having. For instance, if you are actually getting 15 mpg and you overinflate the tires, it might seem like 20 based on the readings. Threfore, you might think it is normal when it isn't. Higher Fuel consumption than normal is also one of those indicators that something is wrong. You need to get a baseline so you have a comparison. Once that is done, you can inflate it the way you want and get a reading then. If you are way off what everyone is getting for your car, something is wrong. If you overinflate your tires, you won't know if your mileage is actually right.