Intresting little road trip - PeachParts Mercedes-Benz Forum

mbzkid · #1 02-26-2006, 03:10 PM

While on a 400 mile road trip with my >2 week old 84 300D Turbo, I ran into a driver from Michigan with a 124 300D. The trunk lid had a BIODIESEL sticker on it. I think it was green with white lettering.

I remember seeing the 124 and thinking, wow that is a pretty nice car, then,I realized, it was a Michigan car! Although we were moving down the highway, I didn't notice any cosmetic imperfections on the car, which says alot for a car from a cold town like that.

We were headed up some huge hills on I80 west in Eastern Pa, thats when I spotted him. I passed the car, while noticing the driver looking at my benz, so I did a double tap of the horn which was retured with beep from the 124. We passed each other a few times while running hard up these hills, and suprisingly the 124 never disappeared from my sight. Can you say ITALIAN TUNE UP? As I exited the highway, I recieved a goodbye beep from the 124, which I, of course returned. Does the sticker represent a website, or does it mean he was just running BIO?

About those Italian Tune Ups:

I was entering the highway at a merge during the day light, and noticed a black puff of smoke from the exhaust. Thats good, but no improvement in an already great running car. Later, a bit before running into the 124, I was running hard up a big hill on the highway, and saw a good sized puff of greyish white and black smoke. Immediatly afterwards, almost all vibration in the steering wheel was gone. Any vibration going down hill was gone, and only a small amount could be felt going up a hill. No where near as much as before. After mentioning what the smoke meant, my passenger mentioned how much smoother the car felt. The idle seems to have smoothed out a bit too.

I can feel some vibration in the steering wheel still, but I doubt the engine is all carboned up again. I have probably become accustomed to the smoother running.

MPG:

I was getting 25 MPG at home, but only got 23 MPG on this trip. I would consider the driving conditions severe. The small 2.5l gas car I traveled with only achieved 21 MPG.

On the trip home I filled up at a run down diesel pump which only had one nozzle for road vegicles. One of the other pumps said that off road diesel was not for on road cars. Not sure what I put in the tank (maybe water and gold?) but it cost 2.60 a gallon, so I doubt it was untaxed. The car ran fine.

Now a quick gas guage question:

I always fill to the filler neck with diesel. Only 10-20 miles down the road, I can see the gas guage has moved off full. When I fill up at 1/4 tank, I can put in 13 gallons. When I fill near the reserve line, I can put in 15 gallons. Being that the car should have a 20 gallon tank, does this mean I have 5 gallons remaining when the car is on reserve? I'm thinking the car has a wacky fuel guage.

pawoSD · #2 02-26-2006, 03:16 PM

That happened to our cars during an extreme italian tune up (we were on the freeway together) I was following our 83, and all the sudden this big "POOF" of black exhaust blasted from the pipe while it was rev'd hard, then it got cleaner, and was running much nicer later on. Same for mine. Was that carbon being blasted out?

It is indeed hard to keep these car's in good shape here in MI.

iNeon · #3 02-26-2006, 03:19 PM

youre not wrong in thinking the fuel gauges are weird, they are.

theyre just about never right and i dont trust it, so whenever i get around 275 miles on the trip odometer, i fill up, i havent run out since.....

well, since i trusted my gauge.

i did replace the sender, but its still not what i would ever call accurate

Diesel Giant · #4 02-26-2006, 03:21 PM

Usually the Italian tune up requires a really long full throttle thrashing for several miles.

mbzkid · #5 02-26-2006, 04:14 PM

Quote:

Originally Posted by Diesel Giant

Usually the Italian tune up requires a really long full throttle thrashing for several miles.

Thats what I did. Out on the highway was the only place where it blew smoke out the back.

Once into the hilly region of PA, I ran it up a "hill" in Slope up to 4500 RPM, for what must have been close to two miles. It slowly went from 3000-4500 RPM over those few miles. Maybe I cleaned out the combustion chambers on the highway, and there was nothing left to clean out when I got into the country.

I figured I would post it because some diesel owners around here would find the story intresting.

dunl · #6 02-26-2006, 06:33 PM

Took my 300SD out on one of our nice flat praire roads here where you can literally see for about 4 miles straight, nothing but fields on both side. Early morning, and topped her off at 105 mph at the beginning of the stretch and just held her there. Nothing for about a mile and then lots of black smoke. Cleaned her out really nice.

MBeige · #7 02-26-2006, 08:54 PM

Quote:

Originally Posted by mbzkid

When I fill up at 1/4 tank, I can put in 13 gallons. When I fill near the reserve line, I can put in 15 gallons. Being that the car should have a 20 gallon tank, does this mean I have 5 gallons remaining when the car is on reserve? I'm thinking the car has a wacky fuel guage.

Exactly the same on mine give or take a few tenths of a gallon. Coincidentally I also get 25MPG consistently. Most I've ever filled up was 16 gal when I ran it for a while even with the (trusty) fuel gauge at R.

Interesting story with the 124.

mbzkid · #8 02-26-2006, 09:41 PM

Quote:

Originally Posted by MBeige

Exactly the same on mine give or take a few tenths of a gallon. Coincidentally I also get 25MPG consistently. Most I've ever filled up was 16 gal when I ran it for a while even with the (trusty) fuel gauge at R.

Interesting story with the 124.

Keep in mind that I'm running winter diesel, so the mileage should increase in the summer.

1,000 miles in almost 2 weeks (the time I've owned the car). A Mercedes will do that to yah'

#9 02-26-2006, 10:56 PM

The SD now will roll over an easy 500 miles per tank...how lovely is that!

320-350 used to be the cuttoff...

...my secret? The tank was slighly collapsed from a plugged vent line building vac some time ago in the car's past.

My SD never needs italian tune ups...once it warms up it sees excess of 4500K rpm each and every day

The occasional 5500RPM for cleaning purposes and passengers who doubt that diesel's can rev high

Brian Carlton · #10 02-26-2006, 10:59 PM

Took the SD home on a 15 mile trip tonight. 18°F. ambient. I usually keep the rpm's at 2000 or so until it warms to 80C°.

Brought it out on the highway after about 1/2 mile in town and it took 8 miles at 2000 rpm to finally reach 80°C. The last 10° took forever.

This is one cold engine if you drive it easy.......2000 rpm or so.

Ken300D · #11 02-27-2006, 10:25 AM

Brandon,

What was your method for dealing with the slightly collapsed tank? Did you apply a low air pressure - and how? I would presume you could do this with something like a bicycle tire pump and that would give you a nice slow control over the expansion.

I don't have any reason to believe I have any tank implosion but one of my vehicles seems to have some air flow when I remove the filler cap. Not a big whoosh but enough that the vent is likely to be partially blocked.

Is the typical vent failure a plugged opening under the car or a collapsed fuel line closer to the top of the tank?

Ken300D

TheDon · #12 02-27-2006, 10:36 AM

i wonder if my tank is collapsed.. weird feeling it is.. i was driving around my neighborhood uphill and i heard a pop like someone pulling a dent. and i just put 25$ of fuel in which was appx 10 gallons and its registering at 1/4 tank from almost on R.. also when i was removing the sending unit i noticed on the top left rear corner it is pushed in a little and a silver piece of metal is welded in that spot.. this car keeps giving me surprises

pawoSD · #13 02-27-2006, 12:57 PM

Quote:

Originally Posted by Diesel Giant

Usually the Italian tune up requires a really long full throttle thrashing for several miles.

Does going 118mph at 5000 rpm for 1.5 miles count?

#14 02-27-2006, 05:24 PM

Hey,

To "check" and repair the collapsed tank, I simply clumb under the car and applied air to the fuel tank vent like while leaving the tank filler cap on.

I used an air nossle attached to our in-garage air system...140psi but you don't have to worry about blowing the tank if you are careful with the trigger.

Basically just put some in...saw how much hissed out when I removed the fitting. Did it a few more times and put on a GOOD strong charge...few PSI at the least.

It holds way more fuel now...along the lines of 3 gallons if I don't top it up and 6 gallons if I do

Total of about 24 can be stuffed in there when really sucking it down low before fillup.

A tire pump would work but you have to find some way to either plug or fill through the tank vent line ...guess you could hoseclamp something up as its only low pressure. Just be prepared to do a lot of pumping

wols0003 · #15 04-07-2006, 04:23 AM

Brandon; dude are you serious? that's a 19 gallon tank. 17 plus 2 after empty. It can't be that easy to change a 19 maximum capacity tank to a 24 max capacity tank.