Hey guys I am n00b who recently got a 1987 300D OM603 turbo. School me in OM603 performance. Is there anything I should do off the bat to pick up some power and/or mpg? My ultimate goal is mpg because this car will never be "fast" but some extra HP and TQ without major downsides is also a plus.

Is there any recommended reading on 603 performance?

Things like EGR removal, or messing with the boost, good ideas? bad ideas?

Where are the common places I should check to make sure my car is running right before I try to upgrade it?

Does the OM603 have ALDA? I have been reading about cleaning out the alda bolts on OM617 motors.

Sorry if it is a broad post, I've always been a diesel fan, but these W124s are the first ones I've owned.

Search: Overboost protection, ALDA, Switchover valve, Bowden Cable.

If the ALDA is adjusted properly, Bowden cable adjusted properly, switchover valve working & connected to the manifold correctly (not blocked by carbon), good air and fuel filters, it should be surprisingly quick (0-60 in around 9seconds & top speed around 125mph).

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Gone to the dark side

- Jeff

Some of GSXR's posts and Replys:
http://www.peachparts.com/shopforum/search.php?searchid=4798989

The "website":http://www.w124performance.com/images/

OnLine manual:
http://www.ps2cho.net/downloads/MB%20CD/W124/Index/602_603index.html

The "Advanced Search" button is Your Friend. (Archives)

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'84 300SD sold
124.128

I just recently bought the car, I actually haven't brought it up to Columbus where I live. It is still sitting down in cincinnati, I'll bring it up here soon, trying to make space up here for it.

Sitting in a box I've got a Mann air filter, power steering filter, spin on fuel filter, inline fuel filter, transmission filter/gasket/drainplug, oil and filter change.

I was going to do all that kind of tune up stuff first.

The car has moisture in the tank and the bottom of the fuel filler cap is rusty. The car idles rough but runs smooth. I have a feeling the tank is rusty and causing a low rpm miss. I have new injector tips and gaskets sitting in a box. I've had it near 120mph and it still gets 30mpg so it can't be running THAT poorly.

I have a gas tank out of a 1994 E320 petrol (along with the rest of the car), will that fit the diesel? The mounts all look the same, the filler looks the same, sending unit looks the same etc. If not I'll go old school with a tank cleaning and re-seal.

Sorry this is a performance/fixing my car thread. Mods feel free to move this back into general diesel if you like.

I'll probably just make this my "build" thread logging the maintenance and upgrades to my car.

Looking at the one link it looks like the euro 300d did not have EGR, should I look for one of those, or just block off my EGR?

I did not know the 300D had a catalyst. There is no emissions testing where I live, removing the cat would probably help the turbo spool up faster.

You're on the right track with filters and fluids.

If you're new to the '87 or the 124 in general, search "Trap-Ox" and be sure you don't still have one. Your rough idle could be the OVP relay if you have an ABS light and dead tachometer also, what's the idle RPM?

Easiest is to put a BB in the EGR vacuum line, disables it. Still there but does nothing.

Rusty fuel cap means that there was condensation, not necessarily a bad tank. Watch your fuel filters for a tank full or so, if you find that you can't develop full power after a half tank or so, you're plugging fuel filters. Use a good biocide in the fuel and a cleaner (Biobor and RedLine are my favorites) for a tank or two and see if it clears up, might need a couple of spare filters and if you're going on any trips, take a quart of cheap ATF to prime the fuel filter or you might run out of battery before priming the engine.

Next look into suspension bushings, common ones on the rear of your car are the "thrust arm" bushings, rear subframe bushings, and lower wheel carrier bushing (the one that connects the wheel carrier to the control arm in the rear). When some or all of these are bad you will get some squirrelly behavior especially when going on/off the accelerator.

Good luck and welcome to the 124 club.

__________________

Gone to the dark side

- Jeff

I do not have a trap oxidizer, the car has not had one for a very long time. The previous owner had it from 140k-175k and it didnt have one during his ownership, and the owner before him maintained it at a friends shop from about 100k to 140k, it never had a trap oxidizer. The owner before that gentleman was the original owner, so the trap oxidizer was removed in the first 100k miles.

In the past 30k miles the car has gotten a rebuilt transmission and a rebuilt turbo, R134 compressor and other related items and waterpump. Within the past 10k it has had front pads, calipers, and rotors. Bilstein HD shocks, new tires, new rear control arm bushings (squeaked like hell), the diff re-sealed along with new differential mounts. Within the past 1000 new radiator, new fan, fan clutch, new front wheel bearings and a few other things.

The tachometer does work, no CEL or ABS light. The idle seems about right but to be honest I haven't driven it in a while so I can't remember. The tach doesn't fluctuate by much, just the whole car shakes. Its not an obvious like 500rpm bouncing up and down.

I've put Diesel911 in a couple tanks to try to dry it out and it keeps coming back. I have a feeling there is a pinhole or something in the tank.

The car does shift very hard. It got slightly better with the new rear diff bushings but still pretty hard.

I'm sort of new to Mercedes, this is the first one titled in my name but my father has had a dozen or so and I take care of a friends collection.

I've also got a 1992 300D 2.5Turbo. The steering and front end feels much lighter on the '92 than on the '87. Should they drive as differently as they do? The '92 is very nice around town, very easy to steer. The '87 isn't *hard* to drive but definitely takes a little more muscle around town. However the '87 really "lays" in the road at highway speeds and is a fabulous highway car. The '92 is down on power but I think thats a fueling issue, or at worst a turbo (202,000 miles), but the '92 is another thread for another time. The '87 kind of drags off line the line from a dead stop but has a lot of power up in the rpms (hoping my tune up will help it a bit down low), the '92 jumps off the line and then looses all of its oomph at higher rpms. I understand the '92 is the 5cyl 602 motor so it could just be different feeling motors. I've never driven any other w124 diesels than these.

The '87 has heavier steering than the later cars.

The soft launch is probably due to a defective or out-of-adjustment ALDA, and thus not enough fuel for a good launch.

__________________

Gone to the dark side

- Jeff

It kind of drags away from the line, but when you get into the boost it pulls like a freight train.

Can you point me towards a good ALDA adjustment how to?

The car also shifts pretty hard, if you let off the throttle slightly before the shift, it shifts even harder. Is this an out of adjustment bowman cable? If so... point me towards a good how to?

If you use the seach feature for ALDA or bowman you get about 10,000 results of posts mentioning one or the other.

The ALDA has a metal seal/cap which must be destroyed to remove. Under that cap is an adjustment, slotted-screw type, with a lock-nut (10mm?). Loosen the lock-nut and CCW the adjustment ~1-1/2 turns is about what most have found works, ... the official FSM adjustment method is based on minimal visible smoke at takeoff.

Very difficult to adjust with the intake plenum on, I've done it twice, this time I think I'll just order the gaskets and R&R the intake.

Test the vacuum/pressure line to it first, if it doesn't hold pressure, it is toast. Some remove the whole thing, but as it is part of your overboost protection, others say don't. I've been happy with adjusting mine.

__________________

Gone to the dark side

- Jeff

Okay, I'll have to look at the ALDA. My friend thinks his mechanic has played with it in the past on this car.

Well I went home this weekend and picked up the car, so now it lives with me for good! It's got some obvious problems that need addressed. I kicked off my ownership with a new battery, died in the mall parking lot, but now I shouldn't have to worry about it for a few years.

-Idles very rough, tach doesn't bounce but it shakes the car. If you look at the motor while its running it seems to vibrate a lot more than the 1992, but with the motor off, the motor doesn't have excessive play in the mounts.

-Shifts like a dump truck, I prefer this to slipping but it still needs to be fixed.

-Reallllllllyyyyy slllllooooooowwwwww off the line, but it does pull well under boost.

-ABS light is now on, after I replaced the battery yesterday.

-It is taking 2-3 starts to get it going when it is cold. It'll start then die, my friend thinks a glowplug or two may be going bad, any way to test them?

Threads are worthless without pics, so here are some pics, if you see anything out of place, call my attention to it.

This is the injector closest to the firewall

This is what all the others look like


Injection pump looks a bit moist, no where near the worst I've ever seen, I am not super concerned about it right now, should I be?


Some oily build up around the PCV elbow, what are peoples thoughts on venting the PCV with a breather?


Now heres the bad part, the fuel tank.




It needs to be sealed, or replaced. I have a tank out of a 1994 E320 petrol, is that the same? It looks the same, it is the same size, the mounts are the same, the filler is the same etc. Can it be made to work on a diesel? If not I'll get the KBS coatings kit and seal this one.

Looks like the gas tank is gunked out from using WVO waste vegetable oil.

I've known the car for the past 40k miles and it hasn't had WVO in it. My friends mechanic has know it since 90-100k miles and for those 35k miles from 100 to 135 it NEVER had WVO in it.

It was owned by a little old lady initially, around 100k miles it got hit when she was pulling out of her driveway, and totalled out. My friends mechanic, bought it, sold it to a new gentleman and continued to maintained it. When the transmission blew up around 135k miles the owner decided he didn't want to fix it and sold it to my friend, via the mechanic. My friend has owned it since then. And in the 3 days I've had the title, I haven't put WVO in it. We've known the car for probably 10 years know and as far as I know it never had WVO in it.

So maybe the lady who owned it before put WVO in it, though I highly doubt it. It was maintained by the dealer up to 100k miles.

Regardless, I don't plan on putting WVO in it and would like to fix it.

A couple tanks of diesel911 didn't stop the water, so I'm thinking its got a pinhole in it.

So, will the E320 tank fit?

I dont know about the tank, some one on here should. On that injector line it looks to me the return lines need to be replaced. After that I would have the motor steamed off to see what if any leaks you have and go from there.

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86 300SDL. 250,xxx on #14 Head. One eye always on temp gauge.. Cruising towards 300K

Is that the braided rubber line? I was on ebay and they only seem sell it in like 2 meter lengths, any way to buy less?

Did an oil change today, along with changing the power steering filter, and the air filter.

The car is noticeably faster on the highway now and my gf says it idles a hair smoother, the air filter was pretty narsty.


Power steering fluid didn't look too bad, I just drained the reservoir, changed the filter, and topped it off
IMG]http://i149.photobucket.com/albums/s50/CincinnatiFiero/300D/DSCN5111.jpg[/IMG]


And heres the car, if anyone can tell me what is wrong with the plate I'll mail you a cookie.