Another problem with the 603 1991 350SD.... - PeachParts Mercedes-Benz Forum

Blevinsax · #1 09-21-2006, 07:39 PM

Okay - another problem to add to the list of my 91 350SD...

Now the car is at my mechanic's shop and will not start. The glow plug light does NOT come on either. I went there myself and tried starting it - the starter turns, but the engine will not start - then white smoke comes from the exhaust. Does that sound like a familiar problem?

He is also having a hard time getting the serpentine belt tensioner to keep the belt tight. He said they installed a new tensioner and tightened it yesterday (when the car would still start) but it would turn over and then the belt would go loose again. Any suggestions?

Damn, this is driving me nuts - I just want the damn thing to run right so I can enjoy driving it instead of leaving it at the shop all the time! Crap!

Hatterasguy · #2 09-21-2006, 09:23 PM

Something doesn't sound right, you don't adjust the tensioner on these cars, they are self adjusting. What did he replace on the tensioner? The little shock? The spring? The arm? The bearing?

Secondly what are the symptoms, it just failed to start? Even without glow plugs it should still start, just with more cranking.

If the glow plugs died suddenly, then check the strip fuse. Its in the black box behind the drivers side headlight, they often fail. Actualy over the winter its not a bad idea to carry a spare.

Blevinsax · #3 09-21-2006, 09:26 PM

Quote:

Originally Posted by Hatterasguy

Something doesn't sound right, you don't adjust the tensioner on these cars, they are self adjusting. What did he replace on the tensioner? The little shock? The spring? The arm? The bearing?

Secondly what are the symptoms, it just failed to start? Even without glow plugs it should still start, just with more cranking.

If the glow plugs died suddenly, then check the strip fuse. Its in the black box behind the drivers side headlight, they often fail. Actualy over the winter its not a bad idea to carry a spare.

Yes, he replaced the shock - he mentioned that it seemed as though something is missing from the arrangement, though.

Yes, it simply failed to start. Cranked fine, but did not start no matter how long I cranked it - then white smoke was coming from the exhaust.

I'll make sure he checks that fuse tomorrow morning.

sixto · #4 09-21-2006, 09:26 PM

Have it towed to a shop with more experience with these cars. If Hattie is an ammateur/enthusiast and knows more than the tech at this shop, anything you're paying this shop is too much.

Sixto
93 300SD

Hatterasguy · #5 09-21-2006, 09:35 PM

Yeah really I havn't even seen the car and I can probably get you close to running.

Umm no offense to that guy but doesn't he have any manuals? I mean if one looks up the belt tensioner on the manual you get a nice little picture with other good stuff.

Without a picture I can't tell you whats wrong with the tensioner.

As for the failure to start I'm not sure. I cannot see how one of these cars simply wouldn't start if the starter was cranking. Glow plugs are important in the winter but as long as its above 50 you don't need them.

Its possible the vacuum shut off failed suddenly somehow. I'd put a tester on that and make sure it holds vacuum and works.

Other than that, internal IP failure? Never heard of that, they don't just fail suddenly.

Any fuel leaks?? Sudden filter clog??

Blevinsax · #6 09-21-2006, 09:42 PM

What would you make of the fine white smoke from the exhaust pipe while I was cranking it?

This mechanic is admittedly lacking in experience with MB, but I have used him for several years on other cars and he is honest and a good person. The reason I took it to him was that he is less than 1 mile from my house and I didn't want to drive the car squealing like mad all the way to my other (German) mechanic 11 miles away. I'm planning to have it towed there tomorrow morning, though.

I'm getting really sick of this crap!!

:fork_off:

I know I will get it all squared away eventually, though!

t walgamuth · #7 09-21-2006, 09:49 PM

it sounds as if the spring on the tensioner may be gone.

tom w

P.E.Haiges · #8 09-21-2006, 09:53 PM

Blevin,

The white smoke is atomized Diesel fuel. THis is normal if the engine cranks but doesn't fire. So U don't have a fuel system problem. Engine is getting fuel but blowing it out exhaust pipe because it isn't burning the fuel.

Check that the GP work, do search on "CABIN LIGHT".

P E H

Blevinsax · #9 09-21-2006, 09:59 PM

See next post.......

Blevinsax · #10 09-21-2006, 10:01 PM

Quote:

Originally Posted by t walgamuth

it sounds as if the spring on the tensioner may be gone.

tom w

That's what my mechanic said, too - looks like a spring is gone. Do those springs break and fly away or what? I drove the car for nearly 2 weeks after having the serpentine belt replaced, so could it have broken in that kind of time frame?

Quote:

Originally Posted by P.E.Haiges

Blevin,

The white smoke is atomized Diesel fuel. THis is normal if the engine cranks but doesn't fire. So U don't have a fuel system problem. Engine is getting fuel but blowing it out exhaust pipe because it isn't burning the fuel.

Check that the GP work, do search on "CABIN LIGHT".

P E H

I'm VERY glad to read that - I was worried about that smoke, but what you said does make sense. Thanks!

greasybenz · #11 09-21-2006, 10:45 PM

Your problem sounds just like the problem i had with my W124. The problem turned out to be the damn glow plug strip fuse that wont allow it to start. Some guys on here claim you can start a 603 in warmish weather without GP's, just more cranking but ive never been succesful at that.

My guess is that the GP relay stip fuse is burnt out. Common problem ive had it burn out on me twice, and this is why i keep a small peice of amplifier power cable in the truck to use it as a temporary fix to be able to start the car. And later on replace the fuse.

Do a search on the glow plug relay strip fuse, its probably the problem of why your car wont start.

Hatterasguy · #12 09-21-2006, 11:00 PM

At some point this weekend I'm going to perform a test. I'll yank the strip fuse and see if the SDL starts on a 40 degree morning.

I will eat crow if a 603 doesn't start without glow plugs at those temps.

On any new MB the strip fuse should be the second thing you change, right after you change the oil. They fail all the time!

greasybenz · #13 09-21-2006, 11:11 PM

Quote:

Originally Posted by Hatterasguy

I will eat crow if a 603 doesn't start without glow plugs at those temps.

Ill eat 2 crows and a cow if it starts. The second time my strip fuse burnt out i had slept over my dads house, early (around 5am) i get up to leave. My dad had the news on and the weather for san francisco showed 56F at present. Tried to start the car with the burnt fuse and it just wouldnt start, i cranked and cranked until the starter started smoking so i stopped and used the amplifier cable in place of the strip fuse to get the glow plugs working.

And then she started up with no fuss

sixto · #14 09-21-2006, 11:18 PM

Has anyone put a circuit breaker in place of the fuse?

You should do some forensics on the fuse. Did it break from age (typical failure mode) or did it blow. If it blew, you might want to test the glow plugs before sending another fuse down the drain.

Which brings up another point - don't just give the fuse a cursory look. Unscrew the fuse to see if it comes off in one piece or two pieces. These fuses can develop a hairline crack but look intact.

Sixto
93 300SD

greasybenz · #15 09-21-2006, 11:25 PM

Quote:

Originally Posted by sixto

Has anyone put a circuit breaker in place of the fuse?

You should do some forensics on the fuse. Did it break from age (typical failure mode) or did it blow. If it blew, you might want to test the glow plugs before sending another fuse down the drain.

Which brings up another point - don't just give the fuse a cursory look. Unscrew the fuse to see if it comes off in one piece or two pieces. These fuses can develop a hairline crack but look intact.

Sixto
93 300SD

Both times they burnt, it was a greenish black in the middle and broke apart in half when i pulled them out.