Just bought a '98 E300 TD. Questions inside
 

Hello everybody. I'm back into the Mercedes fold, for now. I just piked up a '98 E300 with the OM606 turbo. I'm doing maintenance on it tomorrow and want to investigate a few things while I'm there. I'm doing all of the fuel lines, oil & coolant chain (trans fluid has already been done, I replaced the speed sensor plate not long ago - bought this from a colleague, so it's not a complete stranger to me), fuel filters, rear window regulators...

Does anybody have a diagram or p/n's for all of the PCV stuff on top of the engine? It's all oily, so I assume it leaks. if it's all cheap enough I'll just buy it all new.

I want to delete the EGR. Does the ECU use the MAF for anything besides EGR? Is there a tuner that can turn of the codes for EGR?

Diesel purge. 1 can or 2? Hooked up the way I've seen in some videos putting 2 hoses into the bottle, is that cleaning the injection pump too, or just the injectors? Is there anything I should be concerned with in the tank?

Tuning/software. Who are the recommended tuners around here? Not going for big HP, but a few more ponies and a few mpg gains would be nice (and getting rid of the pesky emissions equipment, of course).

EGR Delete here

I have done it, no codes, works perfectly

Thats a long read, thanks. I'll look into it, but if it can be done in the ECU with a flash I'd rather just do that.

Look at the diagram on the page EDBSO linked to. No need to read the whole thread. It's literally one diode and one resistor. Doesn't get much easier than that. Installed it a few months ago myself, and disconnected vacuum from the EGR valve so it will never open. No codes set. :)

While you're in there replacing the plastic fuel lines, swap the o-rings out for viton. I bought mine from fryer power, a nice complete kit: Viton for Mercedes Engines at FRYERPOWER HOME

For ECU tuning, you need someone who will replace the soldered on chips, with a pair of sockets. I know Jeff at Rocketchip has the equipment and expertise to perform this correctly. I've used him a number of times for VW TDI's, very satisfied, I'll be going back to him with my E300. He can dial the EGR duty cycle down to zero too, if you prefer this approach over the diode-and-resistor solution.

As for the PCV, it's only a few parts on our turbos. 65, 68, 71, 74 in the diagram. Thankfully unlike the internet of pipes and junctions like the normally aspirated 606 had.

Attachment 143027

I understand what the resistor/diode mod is, but as stated - if there's an ECU flash option, I'd prefer to do that instead.

Thanks for the link. I'll investigate these orings.


Oh, thats for the pic in the edit. Where do I find p/n's for those? I can't find them in my Worldpac Speeddial anywhere.

The fuel line that goes from the motor side of the shut off valve to the fuel filter is secured by a banjo bolt. There is a small lime colored o ring at the end of the banjo bolt. Buy one of those when you get your fuel line. Mine broke when I removed the banjo bolt, and I had to make a special trip to the dealer to buy a new one. When you change the fuel lines, put a new o ring on the connection between the shut off valve and the injection pump. That o ring causes lots of problems.

Check your shut off valve for cracks. You can do that by wiping it off and inspecting it and then trying, as best you can, to fill it with diesel fuel.

While you've got the intake manifold off, you should consider changing the glow plugs. The added cost is about $90 for the glow plugs and $50 for the reamer. There is a Pelican wiki paper on changing glow plugs and several instructive threads in this forum. Read the threads, because you can run into big trouble if you break a glow plug trying to remove it.

Also, the temperature gauge sender unit is under the intake manifold. If your temperature gauge is acting up, you may want to change it.

I should have mentioned that I have owned a '98 e 300 for more than ten years. It has been my only car during that period. I've enjoyed driving it and really like the car. I hope you have a similar experience.

A): A can of diesel purge is enough and plenty. It cleans the injectors and the pump.

B): Tuning the car doesn't gain any MPG. There's a member on here who chiptuned his '98 E300 who noticed more torque off the line, but didn't increase the MPG.

C): An EGR delete will resolve gunk in the intake. There's a thread on here about it.

D): Check all the fuel lines for leaks especially around the top of the pump around the delivery valves.

Do I need to pull the intake to get to all of the plastic fuel lines? If so, then ya I'll definitely just do the glowplugs while I'm there. I'm very familiar with how to do them. Had one break off in a friends and it took a long drill bit and a slide hammer moving the entire car to get it out.

Thinking of the intake manifold....the entire drivers side of the engine and intake piping is covered with oil & nastyness. I presume this is coming from the EGR or some other way out of the intake? I assume this is common, so maybe somebody can point me in the right direction there?

Yes intake must come off to replace the plastic fuel lines. And FWIW the fryerpower viton kit includes the two o-rings ESchwab mentioned. You will need to source your own copper crush washers though, two of them, for the banjo fitting.

I would also heed his advice re: the cylinder head temp sensor. It's inexpensive, but you have to remove the intake to access it, so might as well replace it preemptively while youre in there.

Yes this is common, there's a large o-ring that sits between the EGR valve and the piping. When the o-ring fails, it makes a mess as you describe. Replace the o-ring while you have the intake off. p/n 606-997-06-45

For me that would be a whole lot of stuff to do in one sitting. What I mean is if you have any problem after work is done, was is something I did and where to start looking. I know it's nice to do a bunch of stuff at once but could be harder to diagnose any problems after the work.

Here are instructions on removing the intake manifold and the glow plugs. I found them very helpful -- especially the intake manifold.

PeachPartsWiki: LightMan's Step by Step Glowplug change

Make sure your battery is fully charged before you take the fuel lines off. You have to crank the starter for a minute or more to get the fuel back into the lines. Do that in 20 second intervals, with 10 minutes or so between each interval, to prevent the starter from overheating.

Fill the canister fuel filter with diesel fuel just before you put it in place. That cuts down on cranking time. Also put diesel in the tube where you will insert the pre-filter. Don't forget the o ring for the pre-filter.

Remove the screen wash bottle and you can change all the o rings on the plastic fuel pipes and remove the stop solenoid quite easily.

you did things the hard way for no reason. everyone around here will tell you penetrating oil and a ratchet and hope for the best. the way that has a 100% guarantee is using an impact gun between 30-40 psi with a fully heated up engine and they will come out (all 6) within 45 minutes. i've done it 3 times and walked a member through the process who vouches for my technique.

I'm a mechanic by trade and own a small shop, but overly anal about my own cars. Tearing the engine down and reassembling is not a problem. I'm just looking to arm myself with as much info as possible before I get started :)