190E Fuel economy???? - PeachParts Mercedes-Benz Forum

190ESport · #1 02-22-2004, 08:53 PM

Hello all pros

Here is one of the most recent difficulties i have been experiencing with my beloved 190E. Lately the fuel economy
of the car is very poor and i cannot determine why exactly it is like that. So i was just checking to compare with all of you who have 190E 2.3 8valve to see if your consumption is the same.
In the pic below you can see how the Economy needle is not at the minimum when the car is cold and in gear (D) with the brake pedal applied (car not moving). When i got this car i think the needle never use to move when the car was idling or when it was in gear like that. Only on a hard depress of the pedal on acceleration or on the highway which is normal im presuming.
I was followed by my friend and we were racing on the highway and he said that the car was smoking a bit grey when it was fully floored (speeds 150km/h and above in summer time).

I had somebody press the gas pedal while the car wasnt in motion and at 4000 rpm there is no smoke but the smell of unburned gasoline if present in the exaust fumes. The car takes in about 12/14 L per 100 km which is terrible. Im wondering is there any way i can adjust the fuel or maybe replace the O2 Sensor or somethin that will improve the fuel economy. I have not noticed loss of power of anything like that.

Recent things i did on the car include:
Oil change with air filter change
Fuel filter changed
Resonator changed - no rear muffler section (straight pipe)

the car speks are
190 E 2.3 8 valve 1987
120 000km on the clock
all original (engine never touched)

All feedback is highly appreciated... thanks guys!!

euronatura · #2 02-23-2004, 09:57 AM

I am not an expert but I do have a 190e.

If my calculations are correct you are getting about 18.27 miles per gallon. This car new is rated at about 20 miles city - 28 miles highway per gallon. Therefore you are not that far off. But if you feel that your mileage has decreased from previous averages then read on.

From what I have read on this forum your poor mileage can be due to a faulty o2 sensor. What I would do if I were you is check the o2 sensor, if bad replace. Check your spark plugs what kind of condition are they in? Only use the recomended copper plugs! Do not use platinum plugs! As for the smoke, this can be valve guide seals? Easy fix if I recall correctly. Also check to make sure that you do not have a vacuum leak anywhere. A large/small vacuum leak I believe can also contribute to poor mileage.

Also, keep in mind your driving style and local conditions. Winter can decrease your average mileage due to the cold if I recall correctly. Also, local terrain. For example, when I lived in Miami I used to average 25 miles per gallon. (@ 10 km per liter) Here where I live now, I have dropped to about 20 miles per gallon (@8 km per liter) but this is due to the mountainous terrain. Lots of going up and down hills/mountains here versus Miami being more flat than a sheet of paper. Also, a lot more passing - stop and go traffic due to buses-trucks-cars stopping where they feel like it and the fact that most roads/highways are only one lane each way.

Iggy

xp190 · #3 02-23-2004, 10:15 AM

I have been trying to resolve a few similar problems in my 85 190E. When I originally bought the car the economy gauge would go all the way to the left indicating very little fuel usage, whenever the car was in gear and stopped. Since that time I have had a timing chain replaced, as well as guides and sprockets, and it has never been the same. Now the guage goes up about 1/5th of the way when in gear and stopped, it only goes all the way to the left when decelerating. I have checked all the vacuum lines for leaks replaced most of the seals and nothing has changed. I also rebuilt the front end myself to eliminate a job badly done by the guy who originally replaced the chain, that didn't help much either.

As far as fuel economy goes not looking at the economy gauge, it is more or less stable. I get about 400km per tank, although I usually fill up when it hits the last quarter, I never gotten into the reserve yet. I fine tuned the electronic controls myself and the car runs top notch, but I would like it to go a bit further on that single tank.

Maybe its is actually supposed to be like this, as far as I can tell the car is not suffering from bad sensors or vacuum leaks, and I maintain it myself so I know what's going on.

But the economy gauge has me puzzled and I have yet to find a fix for it.

xp

sbourg · #4 02-23-2004, 01:36 PM

Our newer 190E does not have an economy gauge, but I am guessing it works like most - measures manifold vacuum. High vacuum would indicate good mileage, abnormally low readings while idling or under decel could be some serious problems, or just a vacuum leak. Check all vacuum hoses and idle air supply hoses/gaskets.

The O2 sensor really should have little effect on mileage. It is only supposed to help lean out the engine from the stochoimetric ideal air/fuel ratio for emissions control. The mechanical adjustment alone should give nearly as good fuel mileage if done correctly. The latter is also is unlikely to change much over many years. More likely in that department would be a leaky fuel distributor. Many report raw fuel pooling below the airflow sensor vane when that happens. Normally, there should be little or none there.

Steve

jeff-abalone · #5 02-23-2004, 02:06 PM

My 1987 MB 190E 2.3L 8V only run 388km to 400km around 44 Liters!

brookspw · #6 02-23-2004, 02:56 PM

The best mpg I've had on my 1991 190e 2.6 (since I bought it 3 years ago) is about 22 on a highway trip. Otherwise, it is 20 mpg all the time.

The car runs great.

Why do I not get better mpg when I hear of others in the high 20s?

xp190 · #7 02-23-2004, 04:52 PM

I think I know why my economy gauge is off, I have to change the head gasket and get a valve job....

started last night, big oil leak and hissing from valves, very irregular. Good thing I got a back up car

xp

190ESport · #8 02-24-2004, 12:26 AM

Thanks to all that answered,

It looks like there is no specific answer to my problem i guess.
I went to my beloved MB dealer and the parts guy is a good bud so i asked him what he thinks on this issue. First thing he said is not to touch the O2 sensor until the light on the dash goes on. Mine isnt on. Second he said trying to adjust the CIS air meter to distribute less fuel/air.

One of you guys said that the fuel distributor can leak?
where exactly is that thing located and how is it connected to the
intake manifold when gas goes trough separate injectors for each cylinder??

By the way my spark plugs are bosch platinum .. replaced 30 000km ago should i consider replacing??

Here are some pics
http://www.geocities.com/tuningbyamg/index.html

euronatura · #9 02-24-2004, 10:11 AM

On the spark plug issue from what I have read on this generous forum is that one should only use what is recomended for the car which are the copper plugs. The platinum ones are not good for the car. If you do a search on platinum plugs, you will find many a thread that discusses the issue.

Iggy

haasman · #10 02-24-2004, 01:03 PM

.. and also using non-resistor type plugs since the plug connectors already have resistors in them ....

Haasman

sbourg · #11 02-24-2004, 04:06 PM

Quote:

Originally posted by 190ESport
Thanks to all that answered,

One of you guys said that the fuel distributor can leak?
where exactly is that thing located and how is it connected to the
intake manifold when gas goes trough separate injectors for each cylinder??

Here are some pics
http://www.geocities.com/tuningbyamg/index.html

The air cleaner housing sits over the airflow meter. If you remove the air cleaner, you will see the fuel distributor mounted on the airflow meter body. It has fuel lines running to each injector, the cold-start valve, the fuel pressure regulator, and a return line. The EHA valve is plastered to its side.

The large vane of the airflow meter is mechanically coupled to the metering plunger of the fuel distributor - the further the vane is pulled down, the more fuel is sent to the fuel injectors. There is a vertical post with an adjustment screw inside on the airflow meter body for calibrating the coupling. It is past the metering plunger that fuel can leak into the airflow meter housing. It is not supposed to do that.

Steve