240D manual mpg - Page 2 - PeachParts Mercedes-Benz Forum

gdav · #16 09-09-2008, 05:00 PM

i have been getting high 20's mainly highway driving to work, i have a 240d 4spd manual. I make sure my tires are inflated properly and I took out all the extra stuff out of my trunk to get that.

barry123400 · #17 09-09-2008, 05:21 PM

If your injectors have never been checked out to your knowledge maybe its about time. Also to check chain stretch and set pump timing is a requirement as well to maximise power anyways with a 240d. As I have stated many times before you want all the power that engine can deliver.

Plus check the valve clearances every 15k makes sense. Also a compression check might not be a bad ideal to make sure the engine has some sembalance of balanced firing. Although a lot of 240ds owners used to report milage of about 24 in many cases and you are using the air conditioner almost continually. You will never know otherwise if the milage can be higher until you do what is fundementally a good tune up.

pj67coll · #18 09-09-2008, 06:12 PM

When I had my 240D with 267K on a rebuilt motor I got between 28 and 32 mpg mixed city/freeway commuting. No A/C but windows open all the time which might have had some drag effect on the freeway. Mileage varied mostly by season with winterized diesel. You don't need to look at the spedo to know when to uphift a manual, you just go by feel.

- Peter.

zeke · #19 10-01-2008, 01:50 PM

Ok, in response to pawoSD question from the future
http://www.peachparts.com/shopforum/showpost.php?p=1980668&postcount=7

I adjusted the valves in June (about 1000 miles ago). The engine has between 250-300k miles on it.
I have no information on the state of the injectors. I bought the car in Sept. 2007 and I have never serviced them.

Engine has minimal blowby (compared to vids I have seen posted here), is really clean, and runs great.

Recently it started to "miss" a bit when cold, but this goes away when it warms up. Also it smokes just a bit - this smoke smells like unburnt fuel to me, with maybe a touch of motor oil in it.

I had thought that this behavior was due to a bad batch of biodiesel I bought last month, because that is when it started missing when cold, the smoke increased and the smell of it changed. I will be filling it up with petroD today, so I can see if this behavior changes.

Still, none of this has influenced the mpg - still sitting at or just below 20.

pawoSD · #20 10-01-2008, 03:01 PM

Missing could be injector issues...popping at the wrong pressure/unbalanced etc.....you might want to consider getting new nozzles or having a shop re-do them....it helped my car quite a lot when I did that. (I just swapped in new Bosio nozzles myself)

zeke · #21 10-01-2008, 03:38 PM

right on, that's the validation I was looking for.
Though I must say she still runs great, even cold, but especially once she gets to operating temp.
I don't find her slow or sluggish at all.

Should I check the timing chain stretch and IP timing anyway?

curtludwig · #22 10-01-2008, 04:10 PM

Hammie, my '83 240D used to average about 28mpg on my 90 mile a day highway commute. They definately get better mpg on the highway.
Always keeping the engine low in the rpm range will result in it carboning up which is bad for it. Theres a balance to be attained here. Probably if you do some good highway driving and get the engine good and hot you won't have anything to worry about.

Weepy fuel lines are fuel getting lost as is not getting all the way to operating temp...

Stevo · #23 10-01-2008, 04:21 PM

Could "bad" injectors really cause that bad a mileage?

I dont keep track that much but my mileage did improve after I got new nozzles from Sean Watts, NOT that much tho.

zeke · #24 10-01-2008, 04:32 PM

Quote:

Originally Posted by Stevo

Could "bad" injectors really cause that bad a mileage?

I dont keep track that much but my mileage did improve after I got new nozzles from Sean Watts, NOT that much tho.

Well, my engine definately gets up to operating temp every day I drive. I don't see any weepy lines and they are all dry to the touch, but the return lines might be due for replacement.

But I guess my question is what my plan of attack should be.....

Until today, I was thinking:
1. Check chain stretch and correct if needed
2. Check IP timing
3. new nozzles

But, based on what I have come up with today, maybe I should
1. new nozzles
2. check chain
3. check IP timing.

any thoughts?

Stevo · #25 10-01-2008, 04:53 PM

Quote:

Originally Posted by zeke

Well, my engine definately gets up to operating temp every day I drive. I don't see any weepy lines and they are all dry to the touch, but the return lines might be due for replacement.

But I guess my question is what my plan of attack should be.....

Until today, I was thinking:
1. Check chain stretch and correct if needed
2. Check IP timing
3. new nozzles

But, based on what I have come up with today, maybe I should
1. new nozzles
2. check chain
3. check IP timing.

any thoughts?

I'm not suggesting you run out and get new nozzles, I would do the 'free' stuff first, you want too know your chain stretch anyway and then check timing.

I really dont know if bad injectors "could" affect MPG that much, maybe so, someone that knows might chime in.

zeke · #26 10-01-2008, 05:19 PM

Thanks Steve, it's not just from this thread, but also from several others I have been reading.

Seems like I am overdue for the new nozzles anyway.