W210 E300 OM606 Bad MPG - PeachParts Mercedes-Benz Forum

kinghais · #1 10-29-2012, 11:45 PM

My 99 E300 TD gets horrible 25 MPG!
My 98 was so much better i could easily get around 35
Recently I cleaned the Intake, it wasn't bad but i could see the valves were dirty! it has 199xxx miles now.
there is no leak of fuel or oil .
deleted EGR
replaced the thermostat 85c.
I dont see why it's gets poor mpg
filled it up few days ago and drove it 139 miles, filled it back up this morning with 6.5 gallons, that is 21 MPG.
what could be the problem???

KarTek · #2 10-30-2012, 07:25 PM

At about 180,000 miles, I installed new injector nozzles and dialed the injection timing a couple degrees to the advance side.

I'm routinely getting 33+ MPG on the hwy with a peak of 37.

DAR2KMR2 · #3 10-30-2012, 08:39 PM

Bad wheel bearings? Dragging brakes? Do all four wheels spin easily when off the ground?

kinghais · #4 10-31-2012, 01:26 AM

Quote:

Originally Posted by KarTek

At about 180,000 miles, I installed new injector nozzles and dialed the injection timing a couple degrees to the advance side.

I'm routinely getting 33+ MPG on the hwy with a peak of 37.

wut???

37MPG
I will do that.
i think injectors r expensive, or can i just get the injectors out and take it to shop get them cleaned out??
and is it easy to do the injector timing?

kinghais · #5 10-31-2012, 01:29 AM

Quote:

Originally Posted by DAR2KMR2

Bad wheel bearings? Dragging brakes? Do all four wheels spin easily when off the ground?

I checked it in summer all brakes and wheel bearings r good
all four wheels spin easily.

Olivier · #6 10-31-2012, 05:24 AM

Quote:

Originally Posted by kinghais

wut???

37MPG
I will do that.
i think injectors r expensive, or can i just get the injectors out and take it to shop get them cleaned out??
and is it easy to do the injector timing?

The injectors are easy to pull out, you need a special socket for it tho.
And when you put them back you need to replace the heat shield washer as they are only single use.

A set of refurbished injector here cost less then 300 pounds sterling. Not that bad for 6 as new injectors.

The timing isn't too bad.
The pump is hold by 3 bolts at the front and one at the back under the manifold and those need to be slacked/ loosen.

If you look above the pump just at the back of the fuel filter you'll see a little Allen type bolt sticking out. Its a 8mm.
When you turn it anti-clock wise you advance the timing.
Clockwise you retard the timing.

I am not sure how to make be sure you moved it 2 or 3 degrees tho, someone here will tell you better

Bad MAF maybe for bad MPG?

Olivier

KarTek · #7 10-31-2012, 05:55 AM

I got some experimental nozzles ( I think they were experimental, maybe just a different variety, not stock), they were like, $40 each. I built my own pop tool and paid a guy $100 to help me build them and provide shims. The shims are the trick because they aren't available just anywhere.

Injection timing is free. The problem is that there's no easy way to measure it and you can put it out of spec. pretty easily. I have a Ferret timing adapter and it's still kind of sketchy to make it read correctly.

TMAllison · #8 10-31-2012, 11:10 AM

Driving style (charging up to red lights) and the type of driving (city vs hwy) has a lot to do with mpg's.

Mine used to avg 30 or 32 routinely on my 110 mile per day commute.

Started working from home and driving 3 blocks back and forth to the grocery store a couple times a week and mileage fell to the low 20's.

kinghais · #9 10-31-2012, 01:52 PM

Idk if i should mess with the Timing cause i never done it and i dont wanna mess it up.
in my area there is only one shop does clean Diesel Injectors, cost $70 to $90 a piece!

My MAF looks ok, today i cleaned it with MAF Spray cleaner.
no CEL light.
it has very good performance, everytime i floor it big black cloud in the back.
I do drive it slow tho. I keep the RPM 2k-2.5k max.
i'm sol and dont know wut to do next

engatwork · #10 10-31-2012, 03:42 PM

What is your driving style? All city?

Quote:

everytime i floor it big black cloud in the back

How often do you run it like this? What is the service history?

kinghais · #11 10-31-2012, 04:30 PM

Quote:

Originally Posted by engatwork

What is your driving style? All city?

How often do you run it like this? What is the service history?

City n highway, like half n half.
I dont floor it all the time, i just did it few time just to feel the power.
Unfortunately i just got the car, I'm the third owner n idk about service history, its been a few month now.
It was a mistake to buy this and sell my 98 e300(always 35mpg).

kinghais · #12 10-31-2012, 04:44 PM

Just filled it up again 4.8 G , n 119 miles. Im sure yesterday i did 90 miles in highway(65mph all the way) n rest was city. So that is 24.7 mpg.
So does anybody think there something wrong ?

Jeremy5848 · #13 10-31-2012, 04:59 PM

The OM606 engine likes to rev. If you lug it around town (like it was a diesel or something) it will load up with soot and that could be related to your mileage decrease. Nothing wrong with letting the engine rev after the oil has warmed. The rev limit for my NA engine is 5400 RPM; your turbo engine should be the same. I almost always run mine up to 4000+ RPM once or twice per drive if not more often.

TMAllison · #14 10-31-2012, 05:21 PM

Filling up in such small increments isn't going to be accuracte, pumps shut off at different rates and then user error comes in to play too.

Check tire inflation and look for fuel leaks, etc.

torsionbar · #15 10-31-2012, 05:54 PM

any diesel shop ought to be able to rebuild your injectors with new nozzles. they pop test them and shim to the correct opening pressure.

another thing you can do is take your intake manifold (both parts of it) to a machine shop to be hot-tanked. mine was heavily caked with oil+soot inside, and the passageways were restricted. it came back from the machine shop clean enough to eat off of.