Hello


I am seeking for any advice to find an explanation for my 300CE34V extreme fuel consumption. It is at ( cruising speeds!! ) 17L/100km = +- 13,8 mpg !!

I must say i did an AMG 3,4 build to the engine with following details:

• crank from a diesel 84mm stroke
• new pistons 90mm + rings + bored the cilinders (like AMG specs)
• measured compression at (a bit high) 12,4 bar. All cilinders 99% equal
• cleaned the inlet channels. Did not change the flow in a big way, more egalising and sharpening the bridge.
• Aligned the inlet / manifold surface ( if you know what i mean ? )
• Std valves are grinded in.
• 3 angle valve seat cuts.
• Inlet cam from schrick, 1,5 mm more lift a bit more duration, 250° (like AMG specs)
• Outlet 2° advanced (like AMG specs)
• Ignition a few ° more advanced
• Lowered the inlet cam advance from 32 to +- 24° (like AMG specs)
• New injectors

The engine runs great ! Way more torque. Idle is like a 12 cilinder smooth. Sparkplugs look great, even a bit lean. Acceleration is very good.


I checked the complete KE Jetronic injection and put in new injectors and air rubber hoses.

All air tight.

Diff pressure is good at 0,4 bar.
EHA valve is new.
Duty cycle EHA is according to specs.
I have no fuel leaks. :-)
Cam advancer is working.





I have 40 years experience but have no more clue where all that fuel is going to ?????


Anybody has any clue what is remaining to check?


Grts
Patrick

How is the distance travelled measured, is it definitely accurate?

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Do you take advantage of that additional torque on a regular basis?

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Jim

I have been thinking about that to !! The speed reading is about correct. Of course it is very very difficult when you are driving around on daily basis to check the distances run. I will do a test to check the odometer against a GPS on the highway for example. Also here in Belgium whe have markings beside the highway with distances every kilometer.

I drive at a normal pace, yes. But the engine has almost never revved over 4k or something. When I check the forums my consumption should be in the region of 12 L/100km or 19 mpg. Not 13,8 !

I have a standard 300-24 CE. I fill the tank and then drive about 700 Km before filling it again.

During 2022, I always recorded around 10.75 l.

Then I changed the cold start valve and, since early 2023, I record almost exactly 10.35 l.

This is on quite local drives of less than 25 Km on winding, hilly roads. Speeds between 0 and 100 Kph.

The only accurate measure is to fill, drive, refill and divide the KMs into the litres.

Good luck.

RayH