Figured it had to happen sooner or later...

It's about 35 degrees outside now...went out for a trip in the E300TD and no start.

The glow plug light cycles as it nomally does, but it just cranks and cranks and sputters a few times in between.

Of course the owners manual is of no help, as it doesn't show where any glow plug fuses are. However I think if a fuse were blown, I wouldn't be getting the glow plug light at all (as on my 240D...)...no?

I don't think one or two bad plugs would keep it from starting, and it has started fine up until this am, so no other indication that something was awry.

Any suggestions?

J.G.

Glow plugs....... replace 'em all. I replaced all mine one year ago, on my '99E300TD. They're too hard to get to, to not replace them all while you're tasking it.

Look at the clear fuel lines for air. You need fuel and heat to fire. You may have a problem with the fuel system, particularly if the tank is less than half full and you parked it nose-up. You can easily figure out whether it is fuel or GP related by eliminating one or the other. Either check the GP's with an ohm-meter or look to the fuel system for air.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

The fuel system can be leaking like crazy, and it will still start and run well. Even when on reserve tank....
Mine leaks about a cup of fuel a day under the hood, and runs/starts like a rocket..

OTOH, if one or more of the glow plugs are going out, it will act as JayGibbs describes....

You are incorrect. I didn't say it was leaking fuel, I said look for air in the fuel lines.

In fact, if there are leaks before the suction side of the lift pump it will lose its prime and cause exactly the condition he is describing...it's very common and there are a couple of o-rings which can cause this to happen. There will be no puddle of fuel under the car because none leaks out...it drains back to the tank and needs to be re-primed.

Cold weather can also make this worse, so don't be so quick to jump to any conclusions, Joe. It could also be caused by a sticking or failing shutoff valve.

It is important to figure out what causes it before throwing parts at it. Throwing parts at a problem is what dealers do...we try to use better diagnostic techniques here to narrow the problem down before reaching our conclusions.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

I didn't say it wasn't air in the fuel system, or any other problem. It could be any of a number at this point.

Glow plug(s) being the chief source of them. Especially at this time ef year, cold weather. It's easy enough to check, without throwing money and parts at it........

I think you may have it with the fuel suggestion...

It WAS parked nose up last night (for the first time in a long time) fuel tank is a little more than one quarter, and there is alot of air in the outboard fuel line at the top of the main fuel filter assy. Also in the line at the inboard lower backside of the filter assy.

I have smelled a faint raw diesel odor under the hood recently, though no "flood" like it was 13 months ago when the o-rings went. I told the dealer to replace ALL...they didn't and was told that mechanic said they "didn't all need replacing!" Bet it's one of the two lines they DIDN'T replace!

So now how do I prime the pump?...I don't see any type of external priming pump like my 240 had?

Thanks-

J.G.

I've started mine on only 2 glow plugs. Its not difficult to do, its a fairly good engine for that.

The glow plug fuses are inside the relay which is located on the right side of the engine bay, bolted to the bodywork, and look like this:

Attached Thumbnails

     

There's no external primer pump. You must (carefully!) use the starter motor when you need to prime the system. It would be nice to have one, as many people as there are who have experienced air leaks.

I haven't looked inside my relay, but I take it that those fuses are not designed to be replaced.

I believe that the relay is on the left side for US applications.

OK, you're onto it now with air in the fuel lines. Until you find the source of the air leak it will be harder to start when less than half full and parking nose-up will make it nearly impossible, as you have found.

I'd first suggest the o-ring on the prefilter be replaced as it is the #1 cause of these leaks. It's also the easiest to fix.

If you want to make it easier to start I would suggest moving the car so that it is not pointing up or adding more fuel to the tank. You may just kill your battery trying to prime it as it is if the leak is bad enough. If you add 5-10 gallons of fuel or move it so the nose is down you will be able to start it easily. Is either of those an option for you?

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

When you say I need to use the starter motor to prime, do you mean I just need to keep cranking until the air is purged?

J.G.

Yes, exactly...that is how these systems are primed, but as I wrote earlier you may not be able to prime it in its current state. You may have to move the car so the nose is either level or down or add more fuel (or both) to get it to start at this point.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

I've got a couple empty fuel cans...my son and I have pushed it so it is now level- or even a little nose down. I'll try to get about 10 gallons in and see what happens.

When you say the o-ring on the pre-filter, do you mean the line that comes out of the top/inboard side of the fillter assy and goes to the front injector? This ALSO happens to be one of the lines the dealer DIDN'T replace last year. I also see this line is a little moist/greasy looking at the top of the injector.

J.G.

I don't believe there is a primer pump on this car.

Have you checked the glow plugs? Electronics?

They should have replaced all fuel lines. I don't know why they wouldn't have..... Here again, it's cheaper to replace all of them like the glow plugs, while it's in for that type of fuel line service. I would have a serious talk with the service manager about this serious neglect of fuel line / O-ring replacement..