can't start 1987 300D Turbo - PeachParts Mercedes-Benz Forum

arnoneh · #1 03-15-2008, 03:21 PM

Got a problem starting my '87 300D Turbo sedan this AM. My wife said she was driving with the reserve fuel light on for a while last night so I thought she just ran out of diesel but this AM, after dumping 5 gal in, it still won't start.

Good battery power, the starter seems to be audibly worked strong, the glow plug light turns off in the usual amount of time, but I just can't get it to crank over.

I'm wondering if it is the fuel pump? Or maybe a clogged fuel filter....I'll replace the fuel filters next but how do I troubleshoot the fuel pump?

Other ideas? Can't think of whatelse it might be, although I'll probably check the glow plugs as well.

Thanks -Harv

kerry · #2 03-15-2008, 04:09 PM

I don't believe there is a primer pump on your engine. Once those engines lose prime, it takes a lot of cranking to reestablish it. I'd continue to crank it in 20-30 second bursts to try to get it primed.

Brian Carlton · #3 03-15-2008, 04:12 PM

Crack the injector lines at the injectors and crank it with your foot on the floor.

See if you get fuel leaking all over the head.

Report back.

arnoneh · #4 03-15-2008, 04:12 PM

THanks for the response. I've cranked it quite a bit but still not able to start it. I'm trying to figure out now if it is the fuel pump..... thanks

kerry · #5 03-15-2008, 04:18 PM

Not likely it is the fuel pump. More likely you have lost prime.

arnoneh · #6 03-15-2008, 04:49 PM

OK, I cracked the injector lines and I see that there is fuel at the injector but when I crank the starter over with my foot to the floor, it does not seem to be pushing out fuel.

Not that I want it to be the fuel pump....but doesn't that tell me it is not pumping fuel? Maybe a clogged fuel filter??

THanks -Harv

kerry · #7 03-15-2008, 04:53 PM

Could be air in the injection pump. Could also be a plugged fuel filter or a bad pump but since the description from your wife seems to point to running out of fuel, the most likely cause is air in the system.

Brian Carlton · #8 03-15-2008, 05:03 PM

Quote:

Originally Posted by arnoneh

OK, I cracked the injector lines and I see that there is fuel at the injector but when I crank the starter over with my foot to the floor, it does not seem to be pushing out fuel.

Not that I want it to be the fuel pump....but doesn't that tell me it is not pumping fuel? Maybe a clogged fuel filter??

THanks -Harv

Fuel filters generally clog slowly.........they usually don't prevent a start the next morning.

Disconnect the line from the fuel pump to the secondary fuel filter and put it in a small container. Crank the engine for 15 seconds and observe how much fuel you have in the container. You should have about two ounces or so. If you have minimal fuel..........the pump is suspect.

If you have decent fuel, I'd reconnect the line and see if you can get it running on WD-40.

Get a helper to crank it and continuously spray WD40 directly into the intake. Removal of the crossover tube would assist greatly with this. Keep spraying even when the engine starts.........because it will be running on the WD for at least 15 seconds. Then, stop the WD and see if it will run on it's own.

bluebird · #9 03-15-2008, 04:12 PM

If it ran out of diesel then you pulled air into the lines, pump, injector lines. Getting all the air out is a real pita. You may need to open the injector lines at the injectors to bleed all the air out. Once you have the nuts on the injector loosened then you need to crank the engine over until you see fuel oozing out the lines then you need to tighten the nuts again and then try starting again with your foot on the throttle pedal to the floor, once it starts keep the revs up above 1500 to ensure that it stays running. Been there done that no fun at all. Unfortunately for you I don't believe the 603 6 cylinder engine has a manual primer pump as the 617 5 cylinder engine does. Good luck on this challenge.

babymog · #10 03-16-2008, 02:22 PM

Yes they can, read the owner's manual, I think it's something like 25 or 35mph and slip it into 2nd.

However, the transmission is old enough to vote and drink, it is a stress that some have not handled well, better off with a jump/charge if at all possible. If you do burn up the transmission, keep me in mind, I might be interested in the car ;~)

a2t · #11 03-16-2008, 11:50 PM

I learned this lesson the hard way too (the running out of diesel lesson).

From now on, 1/4 tank means 0/4. They should of recalibrated those things from factory.

Guess Im cheap, esp at $4/gal.

Oh yeah, it took mine 2 sets of jumper cables going from tow truck (which towed me to diesel station). 1 set on the rigs humongus battery, and 1 on his portable. Tow truck driver kept saying somethings wrong, I said keeeeeeeeeeeeeeeeeeeeeeeep crankin. Eventually she sputtered back to her usual 500 rpm clatter of and idle.

Ive found the best way is to loosen 1st injector rubber line till you see fuel spilling. Then reattach that and move to #2 and so on. By 3 or 4 it usually starts.

For fun, try replacing main fuel filter with it dry and crank.

I did that when I 1st bought it, took a solid 30 min, multiple dead batterys till it lit off. Diesels dont like air in lines, I know that now (and so do you!)

babymog · #12 03-17-2008, 11:20 AM

I replaced the filters in my '87, took about 3min total cranking to run smooth (no prime).

My low-fuel light doesn't come on until the needle is right on the refill/empty mark, then it takes about 12gallons.

Diesel Dan · #13 03-17-2008, 01:05 PM

You might be able to avoid all this battery-killing cranking by hooking up a mityvac to the appropriate fuel line and suck the fuel through the system manually. My fuel system is all re-plumbed for my WVO system, so it's hard to tell you which line you should use, but the line just before the injection pump would at least pull the fuel to that point. Maybe the return line coming out of that banjo fitting on the secondary filter would suck it all the way through? Maybe someone else could chime in here...

arnoneh · #14 03-17-2008, 11:12 PM

Well, I did get it started after several rounds on the battery. However, I noticed some fuel bubbling around the base of the injector closest to the back. I've never taken the injectors out so I don't know what the deal is here: do I need a new seal for it? Or do I just need to tighten it up? Or something worse?

Anyway, this PM I ran down to the store in the car ('87 300D turbo) and parked in an awkward hilly spot where the front end of the car was higher than the back. When I got back to the car 15 min later I couldn't start it...it basically had the same symptom as if it were out of fuel but the gauge read half a tank.....anyway, I rolled it back onto the flat and it started right up. Does that make sense to anyone??

Thanks -Harv

dave1980_300sd · #15 03-17-2008, 11:30 PM

that sounds like bad delivery valve seals. it would make sense with everything else you've described so far. I had the exact same problem with my 190 (parking on an uphill slope, etc.) and new delivery valve seals (and crush washers) was the cure.

hope that helps,

dave