Need repair advice for my 87 300D
 

I purchased a nice 87 300D (150K) last year. I have driven it about 8k miles. Coming back from a trip in November I would have to turn the key serveral times for the glow plug lamp to iluminate before starting. This means one or more of the glow plugs needs replacement. Latter the engine started hammering really bad and it is hard to start and spews grey smoke. Now when I start the car the idiot lites do not illuminate. I think the injectors need rebuilding/replacement. I don't want to blindly replace parts. I have the factory manual.

What is the best way to go about diaganosing the problem in order to not waste a lot of money on needless repairs? Mercedes source sells diagnostic guides. Are these any good? Can I do the work my self? Can anyone recomend a good diesel mechanicl in the Los Angeles (Redondo Beach) area?

It sounds like you need to check a number of things!

I'll start with a few simple things.

If you haven't replaced both fuel filters in six months or so, do so! Add some boibore to your fuel (stops algae growth) Change air filter too! Make sure all six GP's glow. Ohms for each GP should be 03.0 to 08.0 but not 00.0.

Just curious, but does this engine still have the trap oxidizer?

Try this and report back.

BB

For the idiot lights not coming on check the fuses. Make sure none of the spots where the fuses make contact are corroding or look bad. Also, instead of repeatedly turning the key till the light comes on, just turn it to the right for 5 seconds or so, turn off, then turn back on and voila the light should come on. Or, even though the light doesn't come on with a bad GP, the rest of the plugs are still working so just wait awhile when the key is in the on position to start.

Thanks
David

Yes, you can leave the key on until the GP relay/timer clicks, about 30 seconds, listen and you can hear it click from under the hood!

Congratulations on the purchase, and welcome to MercedesShop! As has been said, easiest check is resistance of each plug. My ohmeter reads 1.2 ohms, look for either very high resistance (Open, Bad) or consistent readings between plugs. If they all check OK, have a look at the pins on the relay and the sockets on the plug for corrosion. My 86 SDL (same OM 603 engine) has some corrosion on #5 and #6 pin that sometimes results in a no-glow of those plugs even though they are OK. I'm going to have to clean them up better soon...

With all 6 plugs in working order, the OM603 engine is still known to hammer and smoke a bit on start-up. If one or two plugs are bad, it can really rock the house! :) Let's get the glow plugs squared away first, then there are other tests for the injectors.

As said, before, first check the fuses. While you are checking, go ahead and spin each fuse around a few times in the holder to break any corrosion. You will hear more about fuses, I bet...

Boy, have you come to the right place! :D Checking glow plugs, and replacing them, you can probably do if you have used hand tools before. Checking fuses, ditto.

Best Regards,
Jim

A few questions
 

Thanks for all the quick replys.

1. When I change the the large fuel filter on the 87 300D do I have to purge out the air? If so how do you do this?
2. I want to fill the large filter with a diesel fuel purge/additive. Are there particular brands you recomend. It is ok to us what pepboys carrys? Are there certain products to stay away from that could cause damage?
3. How do I remove the glow plugs to check their resistance? I have the factory manual but it is sometimes hard to navigate.
4. How long do glow plugs and injectors last. If one goes as a preventive measure should I replace the rest?

The OM603 IP is self-purging, be prepared to crank a bit. 30 seconds crank, let it rest a minute. Repeat...

I have no preference. LubroMoly Diesel Purge seems popular.

Good news, you don't have to remove them! Find the relay, under hood, left front fender. Unsnap the protective top, unplug the 6-wire connector, measure each plug to ground. :cool:

There is no set GP 'life' that I have found. Several of us, myself included, will tell you "If it ain't broke, don't fix it" so we recommend replacing only parts that have tested as "bad." I replaced #4 and #6 GP last Fall, there rest are still OK...

Injectors can be rebuilt, there is a debate on quality of parts. If they aren't obviously bad, I'd say leave them alone for the time being...

Best Regards,
Jim

More Glow Plug and Injector Questions
 

I measured an infinit resistance from the connector glow plug 3 to ground. This indicates either a bad cable or bad glow plug.

Question1: In order to replace the glow plug on an 87 300D does the intake manifold have to be removed? If I go to all the trouble to do this than I plan to replace all the glow plugs.

Question 2: Many posts here state to hold on to the injectors. Where can I find a reputable injector rebuilding source?

Check from socket to the end of GP #3 to be sure it is not a bad cable.
You may be able to replace #3 without removing the manifold. I did #4 & #6 in about 30-45 minutes, took my time, used a lot of different 1/4" socket extensions and held my mouth just right... :D
Sorry, can't help you with this one.

Best Regards,
Jim

Injector rebuilds
 

Go to the Robert Bosch Gmbh website to look for a service station near you.
The problem we are seeing with New and Rebuilds is/are substandard injector
"Pintles". Hang on to your O.E. injectors and the servicestation can rebuild
them for you,using your original "Pintles".

IF you actually need rebuilding!

Try the injection "Purge" first.(Lubro-Moly)

Do a search for the above,instructions included!

Could I have a tank of bad fuel?
 

I changed both fuel filters. I filled the large fuel filter with diesel injector cleaner. The car started fairly quickly. No smoke and very quiet. After a while it started hammering. After 3 min. the hamering sound level leveled off (very loud), but no smoke. My last tank of diesel I bought in Arizona at the Califorina border. Could it be that I have a bad tank of diesel fuel. I have about 3-4 gallons in the tank. Should I drain the tank? How do I do this? Or do I have another problem like bad injector(s)?

How do I turn crankshaft for ATF change
 

How do I turn the crankshaft in order to access the ATF drain plug of the transmission torgue converter. I am changing the ATF fluid and filter.

how can I post a new thread
 

I can't find the creat new post or thread button on my screen.

Where is it?

Go back to the title page for "diesel discussion" where all the threads are listed.

The button is on the left side, just below the title block.

also double check the glow plug fuse
 

Folks,

I had an intermittent problem starting my 87 a while back. No glow plug light or on for just a moment. The fuse for the glow plugs ( 80amp?) in the glow plug relay had a hairline crack. Cold it would conduct, warm it would separate, then no glowing. $1 later and a new fuse - it was fixed.

Hope it is simple and cheap for you.

Chuck