My First Post....Fuel Consumption Question
 

Hello Everyone,

This is my first post here. I almost gave up hope, but was thrilled when I learned about your site. I have a 1988 190e 2.3 8v and I've spent twice it's value in repairs (many , many, new parts) and don't have the heart to let it go, instead, I will continue to invest some more time and money and with your support, I believe this car will work like a top. I love this site!

My first concern is fuel consumption. There is about 130,000 miles on the car now and I'm getting about 200 miles per tank, mostly city driving and not abusive. I know I was getting better mileage before, but what is best I should be able to get?
Also, what is recommended to rectify this problem?

I've changed the fuel filter, air filter, and plugs about 10,000 miles ago and I've also cut out the catalytic converter, replaced the oxygen sensor (NTK), center resonator (OEM), and rear muffer (stainless steel performance). Also, I've run Liqui Moly Jectron through the system many times, which instantaneously restores the performance, but that is only short term.

Thank You in Advance

What is the engine coolant temperature? If it is consistently low (below 80 degree C, for example) your fuel consumption will be high.

I have a 85 190E 2.3 with 122K miles - gives me about 260-270 miles in suburban city driving before the red light comes on - 290-300 on the highway - I figured it gives me about 21-22 mpg city, and about 24-26 mpg highway. Zero oil consumption between oil changes (every 3K).

Hope that helps!

You didn't replace fuel pressure regulator, did you?

You should probably replace fuel pressure regulator every 150k km or also, it's cheap and easy to do.

My V8 400E gets better mpg than yours :D

Thanks blackmerecedes for the reply....

The temperature is around 10 degrees Celsius this time of year.
I have not been using A/C either. I'd like to achieve similar mileage as you are....450 km sounds very reasonable.

I had a compression test done approximately a year ago and the result was 174 psi on all four cylinders then. I suppose I should have one done now.

I've only ever used Liqui Moly MoS2 10w40 Synthetic oil ever since I bought it.

I haven't had any problems with oil loss for about a year and half, ever since I replaced the valve seals, but actually about 2 weeks ago I checked the oil and had to top it off...it was a little low. And this morning, I topped it off again, for the second time. There was a spot on the driveway from last night. I checked it over and it's not from the valve cover, but there is definitely a leak from somewhere, hopefully not head gasket...

To: loubapache
 

The temperature seems to hang around 85 and sometimes closer to 90. That is what I would say is the average. The temperature here has been around 10 degrees Celsius.

Does that seem like the right temperature for the engine?

To: agupta
 

Thanks for the figures. I guess you should have a good idea since you own 3 of them :D and a 16v.

I would like to be in that same ballpark for consumption. Sounds like that's the norm.

To: carman850
 

I haven't changed the fuel pressure regulator. Sounds like now may be a good time, considering the one in it looks like it's the original one, and I might as well but new injectors too.

Another thing I forgot to mention is that the car smokes now...white smoke all the time and black smoke on the highway. That is what I've been told from people driving behind me. I'm not sure what that means.

By the way, I love the 400e :D and especially the fact that it has better fuel consumption :confused:

philipminion:

Your coolant temp is normal so rule out a partially open thermostat.

That was an important clue, Black smoke usually caused by faulty Fuel pressure regulator and O2 Sensor.

Sometimes faulty fuel pressure regulator contaminates O2 sensor,
Even you just replaced O2 sensor, it might be already killed by faulty fuel pressure regulator.

Anyway, you can try fuel pressure regulator first.

Hi carman850
what kind of fuel consumption figures do you get on your 400E.
I get about 17-18mpg city (Lots of uphill and downhill driving) and around 26mpg highway on mine.

philipminion
changing the injectors along with the fuel pressure regulator sounds like a good idea to me. They are about $25 a piece and easy to replace. You might also want to have the fuel distributor checked. If compression was good 1 year ago there is most likely no reason tho have one done now unless you can the car low on oil or something like that.
Engine temperature seems about right.
Any problems with the idle? rough? intermittent shaking at a traffic light?If you had the cat cut out you might be looking at a backpressure problem.
Best of luck and keep it up!

2 months ago, I got the same mpg as yours, but now it's winter time, they switched to winter gas and I drive short distance per day(10 km oneway), I am getting 16 mpg on city drive, and haven't driven too much on highway since winter came.

It's not very cold yet, I will feel lucky if I get 15 mpg in January.

Thanks for the reply, carman850.
Looks like both our cars are were they should be in terms of fuel consumption figures. They do have about the same milage down.
What does yours look like?
Mine is desert taupe on cream interior and upgraded to '94-95 hood and euro headlights. I also have ASR.
Happy motoring and drive safely during the wintertime.
F.J.

loubapache:
 

Well, I've already changed my radiator, water pump, thermostat, coolant level sensor, drivebelt, auxiliary fan switch, I've run Liqui Moly Rad Clean and flushed the coolant many times, ....that's all I remember for parts that pertain to the cooling system.

carman850
 

Let's say I replace the fuel pressure regulator, how will I know if my 02 sensor is functioning properly?