Poor fuel economy

[cavaliers16]

I've searched around a bit about this problem, but each case is slightly different. As I've heard, the 300D gets around 25 mpg city and 30+ mpg highway. Mine gets 15-17 mpg city, 21 highway.
So, things I've checked:
-Filters, screens
-ALDA
What's next? Should I check the timing chain stretch (it has never been replaced)? Should I have the injectors pop tested? I can live with low mileage but it has been getting progressively worse. The PO two owners ago (owned the car for 8 years) kept a log of mileage that I found in the glovebox. He was averaging 29 mpg at the beginning of his ownership. At the end it was averaging just 25. I'm inclined to think timing chain but that will be expensive to fix- one of the many problems with the low income high school job .

BTW- it burns no oil

[BenzDieselTuner]

try running some Diesel Purge through the system, and then start always adding Powerservice Cetan booster to every fillup...this should help some....

[FamilyGuy]

Check your diesel return lines and see if they are moist / wet after a drive. It is a $12 fix if they are leaking

[cavaliers16]

Originally Posted by FamilyGuy

Check your diesel return lines and see if they are moist / wet after a drive. It is a $12 fix if they are leaking

Again, thanks for the reply, but no such luck. I replaced all the rubber lines in the car when I outfitted it with the veg system. The steel lines on the bottom of the car are corroded, but (AFAIK) they do not leak.

Fuel leak. If you are not blowing out alot of black smoke, that's most likely the problem.

[cavaliers16]

Originally Posted by ForcedInduction

Fuel leak. If you are not blowing out alot of black smoke, that's most likely the problem.

It blows a little smoke, but it is more gray in color. It usually smoke on startup for about 5 minutes then the smoke goes away. Could my odometer just be messed up? Just this afternoon I looked at the fuel gauge and trip meter- fuel gauge nearly empty and the trip meter was at 301.1 miles .

[cavaliers16]

I was just thinking about EGR- my car doesn't have it, right? I'm thinking that's 85 and on (?)...

[BenzDieselTuner]

i go about 400 miles every tankful.......but then im using fancy amsoil fluids and have an intake/exhaust and stuff, plus i run on used veggie oil......

[cavaliers16]

I have actually already done that, thanks for the reply though.
I am using the Powerservice stuff every tank. I ran just about half a container of diesel purge through the sucker about a month ago with no noticeable effects.

[t walgamuth]

Originally Posted by cavaliers16

I've searched around a bit about this problem, but each case is slightly different. As I've heard, the 300D gets around 25 mpg city and 30+ mpg highway. Mine gets 15-17 mpg city, 21 highway.
So, things I've checked:
-Filters, screens
-ALDA
What's next? Should I check the timing chain stretch (it has never been replaced)? Should I have the injectors pop tested? I can live with low mileage but it has been getting progressively worse. The PO two owners ago (owned the car for 8 years) kept a log of mileage that I found in the glovebox. He was averaging 29 mpg at the beginning of his ownership. At the end it was averaging just 25. I'm inclined to think timing chain but that will be expensive to fix- one of the many problems with the low income high school job .

BTW- it burns no oil

i never saw how fast you are driving. if you drive very fast, this might be about right.

brian is getting 29 but he drives very slow. for me driving 75 on the highway i usually would get 22 or 23. if you are driving faster 21 may not be too bad. also what tires are you running? if you have very large ones and arent correcting mathematically you may actually be getting 24.

so speed is a question and as noted above checking your odo against the mile markers. i always also check my speedo against the mile markers too. sixty mph will take you one minute to go one mile.

tom w

[cavaliers16]

Around town: 25-40 mph
Highway: 55-65 mph

I'm going to try building a pop tester for the injectors- we'll see what happens.

[t walgamuth]

if it is running really well, then i would suspect the odo.

what about your tire sizes?

tom w

[cavaliers16]

Tires are stock size: 195-70/R14
It has good low end power and great high end power. I usually don't drive on the highway but when I do it is very smooth at 65 mph. I'll have to check the odometer against the Volvo's odometer.

[cavaliers16]

Ok, rechecked the ALDA- it is fine. I took the valve cover off- the valves need adjusting bad. There is tons of room on the exhaust valve on #1, and the rest are incredibly tight. I don't know how to test the timing chain stretch though.
For the odometer, I checked the trip meter (what I've been using to calculate mileage) against my dad's Jetta. My odometer marked out exactly 4.0 miles, his marked out 3.8. This is not helping my cause- it means that I am getting fewer miles/ gallon than I originally thought. His is a "new" car (a 97). I'm going to build an injector pop tester this week and do a valve adjustment next weekend.

I have one quick question on the valve adjustment: When I tried to do it today with flat wrenches (it didn't work) I couldn't rotate the engine. I know it has to be turned clockwise, but it wouldn't turn. If I turned the power steering pump bolt or the engine bolt it met heavy resistance. If I put a lot of leverage in it the whole engine moved. I needed to turn the timing chain sprocket bolt about 1/8 in. to get the engine to turn again. Every time I turned the timing chain sprocket 1/8 in, it would stop (same resistance). Then I would turn the power steering pump bolt and the camshaft turned maybe 1/10 turn until it stopped, when I would turn the sprocket again. Repeat several (hundred) times. Why is this happening? The car is in neutral.