BAD gas milage, what do i do?!
 

So for the past few months my car has been eating gas like none other...like 10m/g, thats kinda rediculous and kinda has a rough idle...So iv ben reading up and now know that the EGR valve can be responsable for both of those...I was wandering where that was, i looked but had no luck...Also what else could be causeing it? Here are the things iv had done in the last few months.

most recent
1. Oil Change (3weeks ago)

Tune up a few months ago

2. New Plugs
3. Air Filter
4. 02 Sensor
5. Fuel Filter
ETC...and what else they change, can't really think of anything else too important to the mileage.

Thanks in advance:D :D

hey did you try the r16 timing retard transistor removal?
also what helped my 92 300ce bump up in gas mileage to 16 m/g was using injector cleaners...i would suggest pro-gard Chevron with their cleaning additive...
i actually used duralube injector cleaner...but i'm switching to chevron cause my mbz service guy said that the techron is a good cleaner....
i bumped from 12-14 m/g to about 15-16 mpg....so i'm going to use the cleaner for three more tanks...
hope this helps...

Mushedroom,

can you be any more specific about this...
"hey did you try the r16 timing retard transistor removal? "
I have not heard of this before.

R-16 is a resistor, and only remove it if you're using high-octance fuel and want a little more poke. Otherwise, don't touch.. it won't affect fuel consumption.

Rather than using injector cleaner, why not just replace the injectors. The M103 engine injectors are easily accessible. Just a thought. I am a huge fan of preventive maintenance.....:D

That actually sounds like a good idea, here are the parts I think I need, tell me if im wrong:

1. Fuel Injector (C1000-13519) $24.78
2. Fuel Inj Holder O-Ring (C1031-14304) $0.30
3. Fuel Injector Holder (C1030-14296) $0.93
4. Fuel Injector Seal (C1010-14297) $1.26
THANK YOU FAST LANE!!!

I think this is all I would need, and if I needed 6, a total comes out to $163.62...Now if you ask me, that sounds very cheap for all new injectors. Please tell me if im wrong.

Thanks for all the info:D :D

Hey don't you think that if you bought a fuel injector, u'd get the seal and the ring??
Maybe... :rolleyes:
Just a thought:D

Have you check the fuel pressure with a fuel pressure gauge and see if your fuel pressure is too high?

If fuel pressure regulator is bad, it leads high fuel pressure, which sure causes very bad gas mileage.

Hope this helps.

Here's another idea to throw in... vacuum leaks. Last winter I was only getting around 16 mpg. I took it in to discover that there was a vacuum leak coming from the hose that hooks into the idle air control valve. Now I get around 24-25 mpg. Another symptom of vacuum leaks is rough idle. I can't guarantee that this is your problem, but don't overlook the obvious. By the way a properly running 300e should be getting around 20-25 mpg...

25mpg!! I wish!! I'd LOVE 20mpg, Thats highway right?

1. How do i go about checking the pressure?

2. Where should i start looking for leaks? I know u should spray some liquid just to see bubbles, IF you can't tell...More like where is the air control valve...

Sorry, im still pretty novice at the vacuum and fuel system. Never had any problems, until now:rolleyes:.

But hey, the more your car screws up, the more you learn:D

Thanks:D :D

Bad gas milage
 

Chris;
In the original post you stated the oxygen sensor was replaced,Did you check the fuel mixture after the sensor was installed? The Lambda meter should oscillate around 50/60 percent.
I don't think your 87 300e has an E.G.R. valve.
M.F.

Anyone know if there is a thread posted on how to do this?

"R-16 is a resistor, and only remove it if you're using high-octance fuel and want a little more poke. Otherwise, don't touch.. it won't affect fuel consumption"

Does it work for my 1990 190E 2.6? Where is teh resistor located and what is the general process for removng it,.does it noeed jumped or just removed?

Christopher

Christopher
Search for R16 or R-16 and there's more than you'll care to read

Chris17h, you can often hear a vacuum leak under the bonnet, so check it out. Should be, well, a sort of, vacuum leaky sound. Check all the pipes.

R

Actually that is a combination of city/highway. Highway is more like 26-27... Just out of curiosity how long have you owned the car? Has it always had bad fuel economy?

Yes, that one way to do it, just make sure that it is a non-flammable liquid...or else you might not have to worry about bad gas mileage ever again! :eek: A better way (I feel anyway) is to stick a piece of tubing in your ear and with the other end listen where the vacuum lines interconnect. You should hear a whooshing sound as you get close to the leak. The noise will get louder or softer depending if the end of the hose is getting nearer or farther from the source of the leak.

The idle control valve is located under the air cleaner assembly. To get access you must remove the three bolts holding the air cleaner assembly to the engine. There should be two 10mm bolts located near the cylinder head and on the opposite side there is a third located perpendicular to the ground. It's hidden so you'll have to look carefully. After that remove the vacuum hose on the top of the air cleaner and air intake and lift it off the engine. The idle air control valve is located in front of the distributor and looks like this:
http://img.eautopartscatalog.com/live/C403024259BOS.JPG

Mine wasn't acually split at the valve itself but underneath the manifold... Again this fixed it for me but your problem may be entirely different. You might want to get a tech to diagnose it for $50 rather than spend $500 in parts only to find out that you've replaced all the wrong parts. But if you're a die-hard do it yourselfer I'd start with the vacuum system and work our way up. Just a thought.

Regards,
David

Thanks David,

Yeah, even since i got the car from my dad it had not so good gas milage, but it's seeming to get worse. I put in a full tank then 3-4days later it needs more gas. Somewhat anoyying.

Hey i have an off topic question, does anyone know how-to use a Coolant Pressure Tester, i gotta find my coolant leak today, so im going out to AutoZone and renting a tool.

Thanks again