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  #1  
Old 11-15-2006, 07:09 AM
Coming back from burnout
 
Join Date: Jun 1999
Location: in the Pacific Northwest
Posts: 2,274
Poor mileage on my 85 300D--replace Injectors or IP?

I am having extremely poor mileage, somewhere around 16 to 18 mpg. This summer it was better at 21 mpg. I've heard that the standard for these vehicles is somewhere around 27 mpg which I once got even with a worn Injection Pump and a bad engine and stretched chain, but that was before I replaced engines. I know Brian is even getting 29 mpg on his 300SD.

On my new engine I am having "mileage" problems.

I'm pretty experienced with Diesels and I know all the leaky rubber line, ALDA, stretched chain & IP timing checks and I have done them. I have already replaced my chain and retimed the pump and replace all those leaky rubber hoses between the injectors.

Something is instinctively telling me to replace the Injectors or IP. I have a spare IP but having just gone through the exercise of pulling mine the last time when I changed the timing, I'm not thrilled about the huge Plumbing Job one has to do to switch it.

I know where a good set of injectors is. The trouble is they have been "exposed" for two months to the elements. Back in August, I found a heavily crashed damaged 300CD with 230K.I was tempted to even salvage the engine but I didnt have the time. I did however get the Injection Pump and a lot of auxilaries. Unfortunately I left the Injectors exposed because I took the lines.

Would there be any harm in using those injectors if I pulled them and if I blew them out? One thing I have never done is take apart an Injector

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  #2  
Old 11-15-2006, 07:41 AM
Shorebilly's Avatar
Marine Engineer (retired)
 
Join Date: Aug 2006
Location: West Virginia
Posts: 1,268
Interesting.....

G'mornin',

What color is your exhaust??
Have you done "the Purge"??

I would think with that large a difference in mileage, if it is fuel going thru the engine...you would be having nice black cloud following you around. Or you have a heavier load on the engine than you had before...drag in transmission, wheel bearing (but I doubt it would add enough load),......

Assuming that you are measuring fuel added to the tank vs odometer reading....is your odometer working, 100% of the time.....I got very eratic initial mileage readings, using my odometer......found that my odometer works about 90% of the time.....but on occasion, after reversing the car....my odometer quits for awhile, sometimes going to reverse again corrects it....and sometimes just a reset on the trip odometer does the trick.

Try measuring fuel vs a known distance......I will be driving to N'awlins for Turkey Day...1503 miles from here.....so if I stick to my known route a 15 mile difference for fuel stops and such....will be 1% of my distance and should calculate out with a 1% error factor by my way of thinking.....but a fillup and a 100 mile trip on the interstate, and another fillup.....should get you close to your actual mileage....

SB
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Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG
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  #3  
Old 11-15-2006, 07:46 AM
Shorebilly's Avatar
Marine Engineer (retired)
 
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Location: West Virginia
Posts: 1,268
Exclamation Re: Those injectors....

If you can get them cheap......get them, take them to a local Fuel Injection Shop.....have them go thru them, test and set them...then put them on your car....

If those injectors have been exposed they are probably unservicable...but maybe not trashed...yet....

SB

Note: didja ever get your coppers??
__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG
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  #4  
Old 11-15-2006, 07:55 AM
Coming back from burnout
 
Join Date: Jun 1999
Location: in the Pacific Northwest
Posts: 2,274
Odometer

I've heard all that stuff about odometer error, but I drove to NYC and back yesterday and used 16 gallons and normally on a highway run like that I could make it on probably 8 gallons or less. I don't think its the odometer. For awhile I believed my Tank Level indicator was acting funny, but that was not true either. yesterday's trip confirmed it definitely.

BTW my Mercedes is the exact same color as yours, Midnight Blue.

I used to work down in Louisiana up in Saint Francisville just after school. On weekends it was too quiet so I would head into Baton Rouge or even go to New Orleans. Now when you are 24 years old, New Orleans is definitely a very interesting city!
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  #5  
Old 11-15-2006, 07:56 AM
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Location: Rochester Hills, MI
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Your expectations are a little high. See the attached PDF.
Attached Files
File Type: pdf Find a Car.pdf (40.7 KB, 211 views)
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Adam Lumsden
(83) 300D
Vice-President of the MBCA International Stars Section
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  #6  
Old 11-15-2006, 08:24 AM
Coming back from burnout
 
Join Date: Jun 1999
Location: in the Pacific Northwest
Posts: 2,274
I'm not asking for Free Miles

Quote:
Originally Posted by rg2098 View Post
Your expectations are a little high. See the attached PDF.

I appreciate the info, but on the highway, a full tank would take me from New Jersey to Boston! My mileage is so creepy, I thought I had a Hole in my tank, which I don't
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  #7  
Old 11-15-2006, 09:24 AM
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Join Date: Jun 2004
Location: Southeast Wisconsin
Posts: 1,661
I average 21 to 22mpg from my 85 300D. I think only the e-bay 617 engines get 27mpg! Winterised diesel drops mine to 18-19. It sounds like normal milage to me. If you drive it like you stole it that is...
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1959 Gravely LI, 1963 Gravely L8, 1973 Gravely C12
1982 380SL
1978 450 SEL 6.9 euro restoration at 63% and climbing
1987 300 D
2005 CDI European Delivery
2006 CDI Handed down to daughter
2007 GL CDI. Wifes

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  #8  
Old 11-15-2006, 09:50 AM
Banned
 
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Firstly, the winter fuel has definitely arrived and both the SD and SDL just got severely whacked on mileage. The SD has dropped into the 26's and, last night, I put 10 gallons in the SDL and it got 25.5. The guage was moving down so fast that I was dumbfounded.

So, nobody here in the NE is going to get anwhere near 30 until next spring.

With regard to the IP, I'd seriously doubt that that's your issue unless you've got a horrible idle and one plunger on the IP is non-functional.

Injectors can be a contributor, but, if one injector is not firing correctly, the fuel economy might drop 5% or so. It's not going to be the major source of the problem........if.........in fact it is a single problem.

I'd be more inclined to suspect IP timing. This procedure is fraught with risk in terms of getting it where it needs to be without error. The engine will idle perfectly smooth and will drive OK, but a little sluggish, but the fuel economy will be terrible.

What's it feel like below 2000 rpm? Perky.........or a bit doggy?

The SD picks itself up and goes.........I rarely need more than 2000 rpm.........except for the 3-4 shift when accelerating up to 55-65 mph.
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  #9  
Old 11-15-2006, 09:56 AM
riethoven's Avatar
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Quote:
Originally Posted by Wodnek View Post
I average 21 to 22mpg from my 85 300D. I think only the e-bay 617 engines get 27mpg! Winterised diesel drops mine to 18-19. It sounds like normal milage to me. If you drive it like you stole it that is...
I think your mileage is lower than the average. I have a 1985 W123 Wagon and get 24 around town and 28 on the road. We took my wife's identical car to Florida and cruised at 80MPH most of the time and still got around 23 MPG. We also had a full compliment of luggage and five people in the car.
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1987 300TD x 3
2005 E320CDI
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  #10  
Old 11-15-2006, 10:06 AM
Coming back from burnout
 
Join Date: Jun 1999
Location: in the Pacific Northwest
Posts: 2,274
I've had these cars for quite some years...

Quote:
Originally Posted by riethoven View Post
I think your mileage is lower than the average. I have a 1985 W123 Wagon and get 24 around town and 28 on the road. We took my wife's identical car to Florida and cruised at 80MPH most of the time and still got around 23 MPG. We also had a full compliment of luggage and five people in the car.
They aren't super economical and they do consume some gas (diesel) but 22 to 25 mpg I could live with. I know mine is low based on the fact that I haven't changed my routes or trips much.
As I said a Full Tank easily took me to Boston a few years ago and would last me a week of commuting. I could live with even 20mpg. But at 15 to 16 mpg, something is definitely amiss.

I dont know why people dont suspect injectors. I had a bad Ip once and thats basically what it was, trash. The car went from a dog to a perky peppy driver after i changed the IP. The Shop that checked the bad one basically said the ALDA was non existent and 3 out of 5 injector barrels were shot and something else ( I forget) was non existent. Everyone else said " Adjust this and adjust that and you will be fine..."

That being said, i will probably replace my Injectors and Pump and my mileage will even get worse , always seems to be my case. Later on I will find out my daughter is siphoning off diesel heck you can't stop a tinkerer from tinkering...I just want to do it correctly. I mean can't Injectors go South? They are fallible, too. (After all, I am also)
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  #11  
Old 11-15-2006, 04:11 PM
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Marine Engineer (retired)
 
Join Date: Aug 2006
Location: West Virginia
Posts: 1,268
Arrow Injectors, timing, and fuel mileage....

Howdy,

First my 300D is definately getting between 26 and 27 MPG......

I drove to town today, and this thread popped into my head.....began thinking about LATE timing......we really can't gather enough info with the instrumentation on our carz....on my ship's engines I would know each cylinder's cooling (jacket) water temp in and out, Exhaust Temp, nozzle (injector) cooling water temp in and out, piston cooling water temp in and out (yup we had water cooled pistons), fuel temp, and had an indicator cock that we could attach an instrument to and find out compression and firing pressures.....and pull an out of phase indicator card and see what the pressure was inside of the cylinder as it fired and moved thru it's stroke.....however I got to thinking, if the injection timing was a tad late, the fuel would be burning a bit further after TDC....and thus not create as much HP....so it would require more fuel to develop the same power......

A bum injector can/will do many things.....it all depends on what it's doing....it generally shows up as inefficiently burned fuel...black smoke....and sometimes as a loud knock....with these little diesels, I don't have a clue....if you really suspect the injectors...get the other set, have them tested and set.....then swap them with the originals.....and then have those tested if ya really wanna know......

If the car is running smoothly, I doubt it's your IP...unless it's out of time....or really trashed.....you can also take the IP to the Injection Shop and have it put on a calibration stand.....ask if you can watch.....it will tell you exactly how much fuel is pumped for each stroke.....actually 1000 strokes..and you divide it out......you will see the actual fuel pumped in 5 graduated cylinders.....and will instantly know if one or more are not working up to par......I have already written way too much....It would be difficult to explain hoe an injector's plunger's helix works within the barrel here.....

Sorry, I got carried away......but if you're interested I could recommend some books that you may possibly find at a library.....

SB
__________________

Diesels:
'85 300D, "Max, Blue Benz", 155K, 27.0 MPG
'84 190D 2.2, "Eva, Brown Benz", 142K, 40.2 MPG
'77 240D (parts car)
'67 Eicher ES 202 Tractor "Otto" (2cyl, Air Cooled, 30HP)
Gassers:
'94 Ford F-150, "Henry", 170K (300 Six) 17.5 MPG
'85 190E 2.3, 148K....Parts Car
'58 Dodge W300M Powerwagon (Flat Fenders) Less than 10 MPG
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  #12  
Old 11-15-2006, 05:12 PM
F18 F18 is offline
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Carrameow....how many miles do you think are on the "new engine" and the injectors? A couple hundred thousand miles on thoughs injectors is nothing unless the engine was totally neglected.
I would do a valve adjustment first.....I know you don't want to hear about adjusting anything but it does not cost anything just time. A simple Valve Adjustment can breath new life into an engine...can restore like new performance and economy if the engine is in good running order.
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FRED

Daily Driver: 98 E300TD 199K
Hobby Car: 69 Austin Mini
Past Diesels: 84 300SD, 312K
87 300SDL, 251K
94 Chev. K-1500 6.5Ltr.TD, 373K
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  #13  
Old 11-15-2006, 09:14 PM
Coming back from burnout
 
Join Date: Jun 1999
Location: in the Pacific Northwest
Posts: 2,274
adjustments

Quote:
Originally Posted by F18 View Post
Carrameow....how many miles do you think are on the "new engine" and the injectors? A couple hundred thousand miles on thoughs injectors is nothing unless the engine was totally neglected.
I would do a valve adjustment first.....I know you don't want to hear about adjusting anything but it does not cost anything just time. A simple Valve Adjustment can breath new life into an engine...can restore like new performance and economy if the engine is in good running order.
Yes, I did the valves also, the IP, the chain, and with EGG on my face I think I found the problem...a fuel system leak that didnt show readily because of the heavy rain we've been having in NJ the last week...I won't know for sure until tomorrow..
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  #14  
Old 11-15-2006, 10:41 PM
Registered User
 
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Location: Nova Scotia, Canada.
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I was and still am tempted to pass this one up. Seems to be something you know about the car that is not mentioned. It may be in your subconcious with lots of experience. Or it may not exist at all. At a twenty five percent or more decline from normal average fuel milage there should be a clue. Have you really made sure car is not dumping fuel at speed. Might not hurt to bring engine up to mid speed in your driveway for a minute and have a careful look for any fuel drips on the ground. It might not leak at idle. Disable the egr valve and make sure it is closed up as well. Probably done already. Number one element on any older pump is the most likely to be off if any element is. The result of too much aggression or not using common sense for timing attempts in the distant past for example. Does car feel normally peppy compared to other examples you have driven? Idle better, average or worse than other 617 engines you are familar with? No I do not disagree with your thought it might be the injectors or pump either. Or an amalgamation of many sub standard things. As for the injectors that have been out in the weather for a couple of months I just do not know. Oil would have been still in them and any water introduced by rainfall may have kind of homoginized with the existing oil. They might not be bad. If you can get them at a favorable price (nothing or near to it) why not give them a try. Nothing to loose but a little time and I can see no harm really. I suspect the approach you want to take is to narrow it down or find the problem by elimination. How does this engine start at cooler temperatures? This might provide the biggest clue or eliminate some things as well. For example an engine with severly retarded timing will be much harder starting I believe compared with cars of almost equal compression. In cases where I just do not know or have any pretty obvious prime suspects. Ocasionally a good tuneup sometimes reveals the problem or reduces the possibilities to more managable proportions. Make sure your return line to the tank is not obstructed as well.
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  #15  
Old 11-16-2006, 01:00 AM
Registered User
 
Join Date: Oct 2006
Location: Philadelphia
Posts: 81
Quote:
Originally Posted by Brian Carlton View Post
Firstly, the winter fuel has definitely arrived and both the SD and SDL just got severely whacked on mileage. The SD has dropped into the 26's and, last night, I put 10 gallons in the SDL and it got 25.5. The guage was moving down so fast that I was dumbfounded.

So, nobody here in the NE is going to get anwhere near 30 until next spring.

With regard to the IP, I'd seriously doubt that that's your issue unless you've got a horrible idle and one plunger on the IP is non-functional.

Injectors can be a contributor, but, if one injector is not firing correctly, the fuel economy might drop 5% or so. It's not going to be the major source of the problem........if.........in fact it is a single problem.

I'd be more inclined to suspect IP timing. This procedure is fraught with risk in terms of getting it where it needs to be without error. The engine will idle perfectly smooth and will drive OK, but a little sluggish, but the fuel economy will be terrible.

What's it feel like below 2000 rpm? Perky.........or a bit doggy?

The SD picks itself up and goes.........I rarely need more than 2000 rpm.........except for the 3-4 shift when accelerating up to 55-65 mph.
This is such an interesting discussion I can relate to, concerning my newly acquired 300SDS. The economy seems really really bad, and has taken that winterdiesel plunge, and then some! By the odometer, I am getting 15.9 MPG in mixed driving. The best correction scenario might yield 18 MPG, by adjusting for odometer error! Bear in mind this is a stick-shift variant, which one would think should help the economy. The engine seems to run well but makes excessive black smoke; no car tailing me will dare to get close. The RPMs are unusable below 2000 RPM in any gear above first. Well, I can go a lttle below 2000 in second too.

So what engine ailments am I facing? Injectors? Injection timing? Valve timing? Timing chain stretch? Alda? (What is the Alda?) The five cylinder turbodiesel is all new to my experience. As a newby, any insights will be appreciated. Thanks in advance!

Garth

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2001 E320 4MATIC WAGON desert silver/tan, 169K
1986 300SDL black on black, 240K

1984 300 SDS (stick-shift) 209K.....now reborn as a 1983 300SD (stick-shift facsimile of the former 84) 274K

1982 240D (sold!) 264K
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