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1987 300TD W124 sedan
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19 Posts
Discussion Starter #1
Ok fellas,

I can't find an OBD socket on this rig. Engine light is flashing and don't know if it's just a grounding issue in the dash or if it's really a code.

There is no consistent burn on the bulb to tell if it is screaming at me or telling me if there's a dilemma somewhere.

After all of my fuel line and some vacuum line fixes, I'm still getting getting gutless high rpm's before shift, unless I throttle shift. Seems to be getting worse every week or so. And yes, I've been spraying out my vacuum lines off the intake manifold weekly, to insure they aren't plugging up. They've been pretty clean since my first clean up. :surrender:

Thanks for any help.
 

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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17,367 Posts
OBD on a 1987??? Don't think so. OBD-1 started in the early 90s, followed by OBD-II with model year 1996. The generic store bought scanners only work with OBD-2.

The codes can be pulled using a $5 Radio Shack DIY code reader.

Do a search for full details.

Didn't think the diesels had a check engine light, only the gassers. Perhaps your cluster was swapped with a gasser version at some point, as the check engine light is located in the same spot as the pre-glow light.

A flashing pre-glow light would indicate bad glow plugs and/or glow plug relay. On my diesel, the pre-glow light started flashing right after putting in a new wire harness & glow plugs. Glow plug relay was OK after testing, but the OVP relay wasn't. New OVP relay cured it.

I'm also in Sun-D-Eggo. I could give you a help if you need it, just PM me.
 

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1987 300TD W124 sedan
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19 Posts
Discussion Starter #3
LOLOL!!!

Duh on the OBD! Sheesh, what a maroon I am.

The glow plug light is the glow plug light.

What the heck is the yellow lit circle with the dashed lines around it one the left side of the outside temp?? I have no owners manual and haven't seen one online in my searches except for sale, which isn't helping. Owners manuals are generally fluff legaleze and usually worthless.

Now a complete shop manual, in English, that would be good. I like paper manuals better than online so I an mark up notes in the columns. I had and '86 Nissan truck that had almost as much writing from me as factory tech stuff. LOLOL!! I ended up, endo-ing that thing. She wasn't much to look at after that! Gravel road, high speeds, blew front tire, took me over a burm, Magic Mountain got nuthin' on an airborne Nissan Hardbody!

I might take you up on the meet-n-greet. You can give my greasy girl a spin and see what you think. It's really a disappointment because I'm going backwards now. I was making progress for awhile. I think my mileage went backwards again, just no smoke to indicate whizzing injectors, no stumbled on throttle at all, filters and lines clean as a whistle- even emptied and cut open a fuel filter- clean! $&@#^&$%#!!!!

I'm unfamiliar with all the vacuum diaphragms this thing has, no specs to start with either so I don't know where to start in testing them.

I realize I'll never do 0-60 in 2.5 sec with this thing, but it's getting to be a nuisance at stop lights. I'd like to move on to fixing the sunroof and some aesthetics.

Thanks for the reply.
 

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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17,367 Posts
Drawing from my W123/W126 memories, you might want to check if there is a turbo boost vent line that goes from the turbo to a switchover valve to the injection pump.

This line is responsible for triggering the injection pump to go rich when turbo boost conditions are reached.

On the W123s, this line is notorious for getting clogged and will result in lackluster performance provided your turbo is still functional.

My diesel is non-turbo, so no signal line. When your OM603 is operating OK, you should be able to do 0-60s in the 12-13s. It was the quickest off-the-line among the W124 diesels.

Your mystery symbol is probably the brake pad wear indicator.

I can get you a PDF version of the owners manual and factory service manual. You might need it.
 

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1987 300TD W124 sedan
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19 Posts
Discussion Starter #7
444,

Awesome! THX!

I'll have to pull the wheels this weekend.

sbaert,
I don't know why I wouldn't have pulled the line to the turbo, but I haven't. I've pulled all the lines between the ALDA and two other vacuum switches that I have no idea what they do yet. I snapped two off they were so brittle, so I replaced them. I'm pretty sure the turbo is still working because after my initial line cleaning replacement, the car really took off. Since then it has slowly lost pace and why I've cleaned the lines and changed fuel filters so many times.

300E91,
I have that pdf set, it just seems to me it's a little weak. I'm more used to repair manuals that have tables of electrical values on sending units, torque tables and other more useful stuff. Maybe I just haven't run across them yet. The sunroof page is pretty good though. Before I go off and put a big hole in my roof in winter with rain possible....yeees, even in Socal.... I really want to get this engine running tops first.

You fellas have been great. I really appreciate your input.


Brake pad sensors..... sheeeesh, what? The squeal of the metal tattle tales not good enuff for the Germans? ;)
 

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1991 300E
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601 Posts
300E91,
I have that pdf set, it just seems to me it's a little weak. I'm more used to repair manuals that have tables of electrical values on sending units, torque tables and other more useful stuff. Maybe I just haven't run across them yet. The sunroof page is pretty good though. Before I go off and put a big hole in my roof in winter with rain possible....yeees, even in Socal.... I really want to get this engine running tops first.
Look at the ETM subsection for everything on electrical components. It can be especially unwieldy, but cbc atl has done a great job breaking it into digestible pieces: Anyone hosting Supplement 14?

Torque values are included in every procedure. There are tables galore.

Some user-written how-tos are better illustrated with color photos and such. Some of them are linked on the "Misc" page of the manual link I gave you and the host of that site has others at http://w124-zone.com, as well as what you'll find on this forum and elsewhere on the web. Nonetheless, the factory service manual is the standard reference.
 

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1987 300TD W124 sedan
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19 Posts
Discussion Starter #9
Thanx 300E91,

I guess I'll have to look at more stuff then.

The vacuum/turbo diagram will be my next read.

Thanx again everyone, I really appreciate the insight.
 

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'88 300TDT Euro Wagon, 2010 Smart ForTwo, '94 Saab 900S Convertible (classic)
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18 Posts
I just replaced my vacuum pump, which solved a bunch of problems on my '88 TDT - I bought the pump from e bay. Also, you might want to check mercedessource dot com for comprehensive info on the 603 engines and practical upgrades to get them running as intended. Buenos Dias!
 

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Cruise Control
'87 300TD/'90 300D/'94 Quattro/'89 Vanagon TDI/'01 EV Weekender VR6
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52,233 Posts
The stock emissions system from 1987 is now 23 years old, which means all the vacuum transducers and solenoids are prone to failure at any time. Attached is a sketch of the minimum of vacuum-related items needed to operate an OM602*/OM603 engine. You can safely bypass/eliminate the overboost protection solenoid, the blue flying saucer (BFS) and all the EGR vacuum transducers (located under the air filter box).












*OM602 -- this applies only to those engines that have already converted from a vacuum signal to a pressure signal wastegate actuator.
 

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1987 300TD W124 sedan
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19 Posts
Discussion Starter #12
Wow! That's great.

y blue flying saucer is located on the drivers side fender, I noticed in your photo it wasn't there.

You wouldn't happen to have a photo of the exact device your speaking of so I don't yank a vital part in this vehicle lightening I'm going to do?

Also, how do I know whether or not it is a vacuum v pressurized waste gate... besides pulling off the air line, assuming it is pressurized/vacuumized at idle.

I really hate being ignorant about my vehicles. The control systems are new to me and my time has been more limited the last two months since I bought the car, so learning has been way slower than I'd like.

Last question, does pulling the EGR and capping the cigar pipe harm any systems? I was going to do this a month or so ago, but time and a warning from a good diesel mechanic advised against this.... his reasoning didn't click with me, which lowered my opinion a little with him. I'd like to get rid of a soot source being injected straight into the air box, not to mention pulling a ponie or two by keeping the air as cold as I can. Eventually I'd like to put in a frost inject system. The thing with upgrading anything is, it should run right before twinking with it, so one can tell if it was an installation problem or a failure of something else.

Thanks again for the great gouge!
 

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Cruise Control
'87 300TD/'90 300D/'94 Quattro/'89 Vanagon TDI/'01 EV Weekender VR6
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52,233 Posts
You have an OM603, so my little caveat doesn't apply to you. The pic is of my '90 300D which has an OM602 and originally had a vacuum wastegate.

You can safely pull these:



Here's a pic of the EGR removed and the holes capped:



Here's a box of "extras" I removed from the 602 -- the BFS is right there in the middle:



I'm not sure what the cigar pipe is, but eliminating the vacuum signal to the EGR or deleting the EGR completely has no negative impact on any other engine functions.

The original pic I posted really has all the vacuum requirements for your car completely covered. You simply need a source for the ignition switch fuel shut-off, the transmission modulator and the climate control; that's it. One of these days I'll draft up a bare bones vacuum diagram.
 

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1987 300TD W124 sedan
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19 Posts
Discussion Starter #14
Perfect!!

I saw your EGR and cigar pipe cap awhile ago. The cigar pipe is the pipe that your end cap is attached to.

There are two systems for the 87, one is a pot or canister which had problems, the other is the cigar pipe that never had problems. You have the cigar pipe. It's fat in the middle and skinny on the ends...looks like a cigar, especially when it's all rusty brown.

Thanks again. You "spare parts" package helps out a lot. I'll be sure to have a few caps to plug the newly vacant vacuum line ports, at least until I reach in my pocket to buy an appropriately branched rubber tree to fit in their places.

Thanks again Zeitgeist
 

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Cruise Control
'87 300TD/'90 300D/'94 Quattro/'89 Vanagon TDI/'01 EV Weekender VR6
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52,233 Posts
Oh, you're referring to the trap oxidizer and its replacement log.
 
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