'98 E300 TC lockup?
 

OK, so I'm chasing more demons in this car, trying to learn what is working right and what's not... At 70 MPH, the engine's turning atout 2500 RPM. When I step on it gently, the RPM's run up at a rate higher than the speed increases leading me to believe that the TC isn't locked. I'm also getting somewhat poorer mileage than I'm expecting but that may be due to other problems. I'm just exploring all the options.

Any insight?

IIRC at 2500 rpm mine runs about 67 mph uphills and over 72 downhills. Have you checked your ATF level? Mine was over a quart low due to a leaky O-ring seal around the electrical plug connector and was experiencing similiar issues.

****** "MB Garage Only" cap on tranny dip stick... How do you get it off without breaking it?

Snap off the tab and order a new one from Phil for $2.00 or leave off the red tab. You need the dip stick from MB to check it also...

I'm not sure if you are aware of this - the dip stick for these transmissions is supposed to be "MB shop only" so you won't find one living underneath that cap. I bought one awhile back but it would be pretty easy to make one.

If I were you I'd be 100% certain that you do not have a fuel leak from some bad O-rings on/near the IP that would be the cause of your mileage issue. I get roughly 32-33 mpg on summer blend D2 (all highway @ ~75mph).

Thanks for the replies. Now that you mention it, I smell a hint of fuel odor under the hood. It may be nothing but as far as I'm concerned, the only odors under the hood should be some hot oil perhaps but no fuel.

I really need a manual for this car.

What are you expecting? How many miles? Have you run down the usual culprits? Air filter, fuel filters, leaks in the fuel hoses? Prechambers? Injectors?

You could put a dipstick down there but it won't help much. Why don't you go to a dealership and have them change the fluid? That might help some as far as seeing if the fluid is bad and the proper levels since they need to hook up SDS to the car to check fluid temp before they can make sure the levels are right.

I've only had the car about a week and a half so I'm still learning what the "usual suspects" are... :book: My new owner list of things to do includes: Running a Diesel purge, replacing the fuel filter and doing an oil and other fluid changes. I have one bad glow plug which is causing some poor performance in one cylinder. The injector may be carboned up and spraying poorly. I'd really like to get into that prechamber and inspect it's condition and the condition of the injector nozzle. I'm sure this is contributing to the poorer mileage. I'm kinda scared of the special tool list for injector and pre-chamber removal though... :eek:

BTW, the car has 136,000 miles and it's getting 24 MPG combo city/hwy and 29 on the hwy only.

Thanks!

IMO, it would be a total waste of time. See later.

I'd change all fluids. Go to MB for the trans fluid because you don't have SDS.

For this engine, I would be careful but take out ALL the GPs and change them. Don't forget the anti-seize. GP cannot cause poor performance since they are on only when the car starts up and a few mins after.

If you take out the prechamber, you should have the injectors in your hand. Take those down to a diesel shop and run a test. With that, you will KNOW for sure whether the injectors are working well with good pop off pressure and spray pattern or not. I took the injectors out and checked mine at 100K and got one bad injector. Power and smoothness came when that was cleaned. I would suggest doing it every 100K (just the injectors). I don't waste my time with DP (Diesel Purge or Double Penetration) because it is easier for me to check injectors once every 100K as opposed to fooling with the fuel lines and having them leak. Every time you mess with the lines, you might cause a leak.

Not sure what you should be getting but that sounds about right depending on your right foot. I get 33 cruising only at 85

The reason I think the glow plug is causing the poor performance is because some previous mechanic broke it off in the hole and it's been running without one for an unknown period of time. I figured this is carboning up the holes in the pre-chamber and the injector nozzle. It's just not as smooth as I think it should be.

That mileage was obtained on a long trip on flat ground driving VERY conservatively at 65-70 MPH.

It cannot cause poor performance since it just sits there. It might cause harder starting but such is life. I hope you got it for a song since there is that problem. You will need to take the head off to get it out, IMO. People have attempted to drill it out but I almost fawked up the head doing that so I will not advise that. Again, it has little to do with the smoothness other than in starting.

Sounds like you have lost a few mpg. BTW, I am assuming the tires are of the right size and right pressure? I load mine up to "max load" as far as tire pressures

Well, I guess I'll check out the injectors and inspect the pre-chambers. I'll have the injectors checked at a local Diesel shop too. Gonna have to fab up a long 22mm socket for the injectors. I'm too cheap to pony up the $53 for a factory one... :eek: It's probably similar to the one I made to get the military plugs out of the 'mog...

I don't think you can take the prechamber out with the plug still stuck in it. Is it $53? I bought one for way less than that. Cost you shipping back and forth if you want to borrow it. the problem is that you would have to find a thin socket that would be deep as well

Crap, that's right, I forgot about that...:mad: I'll look again into the tool thing. I have a lathe and mill in the shop and I can make some pretty good tools. If not, I can use the prototype shop here at work.

I appreciate the offer though!

Maybe I can at least inspect the prechamber with the GP still in there...:thinking: