1999 E300 Turbodiesel won't start all of a sudden. - PeachParts Mercedes-Benz Forum

dtf · #1 03-20-2004, 05:19 PM

My wife's car, the '99 Turbodiesel won't start. It stumbles and wants to start but doesn't fire up. I've just read that one problem could be air in the fuel lines. The car has 82,000 miles. Can anyone list the possible causes of the car not starting out of the blue like this? It has been well maintained and has been running great.

slowmoe · #2 03-20-2004, 06:12 PM

dtf,

There are several reasons why your car won't start.

1) Battery low on charge
2) Bad fuel - water, gas, gelled etc...
3) Low fuel
4) Air in the fuel
5) Fuel filters old and clogged or wrong kind
6) Glow plugs are bad
7) Glow plug relay is bad
8) Control module for fuel injection bad
9) Control module deactivated because of false "unauthorized start"

First, do you have any "check..." messages on the dash? these would likely give you a good place to start - if you can have the code read. AutoZones do this for free. MB charges $70.

Secondly, are the lights on your rear view mirror flashing alternately red and green? If so, this is a false "unauthorized start"

If there are no messages, I would start with the easiest/least expensive things first.

1) While the car is running look at the clear plastic fuel lines going into and out of the fuel filter assembly. If you can see any bubbles of air at all, the fuel lines and o-rings need to be replaced.

2)Have the battery checked - most Pepboys, AutoZones etc... will do this free.

3) Replace the fuel filters and add a fresh tank of diesel from a station with lots of diesel traffic - old diesel fuel is bad.

4) Pull off the intake manifold and check for current to the glow plugs - if no current then the GP relay, or fuel injection module is bad. If there is current then replace your GPs.

That is about it. If you have air, compression, charge, warm cylinders and fuel - less any electrical insanities - your diesel will start.

Please keep us updated as we are still in the process of learning about these cars on this board. Thanks

Gilly · #3 03-20-2004, 06:39 PM

Pull out the pre-filter and see if there is any fuel in the pre-filter chamber.

Gilly

TMAllison · #4 03-20-2004, 10:12 PM

Have been down this road myself with same car.

You do not state that the "check engine light" is on....or that there are any fuel leaks.

Make certain battery voltage and glow plugs are operating properly.

Assuming no CE, the culprit ought to be air in the plactic fuel lines. You should be able to see it if present with a strong flashlight while a friend cranks the engine.

With good battery and glow plugs it should start after priming pump for 30-40 seconds and continuing to crank a couple seconds after you think it caught.

Once running it should keep running if air is the problem as pump is efficient at removing air from system.

Malfunctioning shutoff solenoid can cause same problem but ought to activate CE on dash.

Gilly points out to check the pre-filter, it has an o ring that is often not replaced during service as it has it own part number and assumption of many is it comes as an assembly. It doesnt.

ohcaptainron · #5 03-20-2004, 11:26 PM

Lots of KEY malfunctions, check key battery or use another key.

coachgeo · #6 03-21-2004, 01:08 AM

siphon a good sample of the fuel out of the tank and look and smell of it closely. Maybe gas went in the fuel tank instead of diesel.

Gilly · #7 03-21-2004, 07:49 AM

It could be a bad key, but the battery in the key has no effect on the DAS system, the battery is only used for the remote lock/unlock features.

The o-ring on the prefilter, if it was forgotten, the engine would only run for a few minutes, so I doubt it was forgotten (unless this is really a shop owner posting the problem). But if the filters weren't replaced on schedule, the o-ring can degrade to the point where air is now being sucked in. Another possible problem if the prefilter chamber is dry is a problem with the fuel shut-off valve (seen that a few times) or maybe the fuel gauge is defective and it's out of fuel. Seen this before too, not on this particular model though. Had a car towed from a shop in Milwaukee to where I worked because it was out of fuel, this was a gasser though. They wanted to replace the fuel distributor!!!

Gilly

trapeze · #8 03-21-2004, 09:16 AM

I just had the same issue with my 99 e300. All the warning lights were good. It sounded like it wanted to start, but stumbled. I was advised by MB to floor it, and then hold the key on for extended time, like 30-45 sec. After 10 or 15 attempts, it started hard and rough, then smoothed out. Turned it off, then started it again, worked fine.

The next day, after sitting all night, I had the same issues. At the advice of fellow posters here, I looked at the clear fuel lines around the fuel pump, filter, fuel shut off valve and found several of these lines had no fuel in them. It showed no indication of a fuel leak.

I had it towed in, (because I am still under starmark).

MB found the fuel shutoff valve was leaking air into the system. They replaced it, all is well now.

The air leaking into the system allowed the fuel to drain down into the tank. Essentially I had to prime the fuel system each morning, in order to get it started.

coachgeo · #9 03-21-2004, 09:49 AM

Get a 30 dollar 12v faucet Purlater fuel pump (the lowest psi one) frome cheapo auto parts and mount it in the fuel line way back by the tank. Temporary mount is fine. Put it on a switch. turn pump on. Look for leaks. If the probelm is an air leak you will now have a fuel leak so inspect closely. The fuel leaking will be because now fuel is "pushed" thru all the lines infront of the 12v pump instead of sucked. When fuel is sucked air is sucked into cracks etc.)

The faucet Purlator should not over pressure the fuel system.

Fire up the car. If it runs now keep looking for a leak. Of course be fire preventitive and look close for fuel leaks onto hot spots and have a fire extingisher ready.

If you do not see a leak and car still wont start then you have something blocking fuel delivery and/or have bad fuel?

dtf · #10 03-22-2004, 09:41 AM

Thanks for all the replies. I am going to check it tonight after work. There is no check engine light so I am thinking with the rest of that it is air in the lines problem. I'll upadte when I know more.

P.E.Haiges · #11 03-22-2004, 10:17 AM

My God, all the things that could affect a no start condition on the newer MB Diesels. No wonder they aren't as reliable as my old 300SD. I don't want any part of the newer ones.

Someone should tell the MB engineers about KISS: "Keep It Simple Stupid".

P E H

BootieNH · #12 03-22-2004, 04:06 PM

dtf, check out my very similar thread on this topic. Same car, just about identical miles. After many headaches and dropping too much coin at two separate dealerships, it appears I finally found somebody who is diligent and pursued the problem as if they owned the car - something all too rare at dealerships. Can't say for sure in your case, but air in the fuel lines was my problem, and is problematic with this car apparently. He replaced O-rings and lines that were allowing air into the system when the car sits overnight. Picking it up tomorrow - have been without it for 1 month now. Unbelievable. But the one good thing after all this (besides all the wonderful advice on this forum), is that I seem to have discovered a highly respectable honest mechanic, who will now get my business from this point forward.

whunter · #13 03-22-2004, 04:11 PM

Hello BootieNH
Please share, others need help too.
Have a great day.

BootieNH · #14 03-23-2004, 10:18 AM

<< please share >>.
I'll assume you're referring to sharing the name of the mechanic. Gladly. Jason Carter - his business is named "Carter's European Auto" and he is located in Greenland, NH. If you're referring to sharing my problem experience, search this forum for my username and you'll get all the gory details.

whunter · #15 03-23-2004, 11:32 AM

I was asking for mechanic and shop name.