W210 Weird Starting Problem - PeachParts Mercedes-Benz Forum

208benz · #1 07-29-2014, 11:07 AM

99 E300D

When engine is cold it will start normal. A normal start is after pre glow, turn key, the engine starts in under 1 second.

When engine is warm it takes longer to start. Usually 3-4 seconds, and will sputter sometimes. This started happening about a year ago and has gotten worse.

I have replaced the tank filter, fuel filter, and pre-filter.

Has anyone seen this?

Thanks,

Mike Nemec

TMAllison · #2 07-29-2014, 11:21 AM

Check for air/bubbles in the fuel lines after its warmed up versus cold, if present, replace all orings.

GregMN · #3 07-29-2014, 12:21 PM

Quote:

Originally Posted by TMAllison

Check for air/bubbles in the fuel lines after its warmed up versus cold, if present, replace all orings.

X2

208benz · #4 07-29-2014, 10:34 PM

No air bubbles in the lines.
Have also parked the car on an uphill slope, starts normal when engine is cold.

jay_bob · #5 07-30-2014, 05:07 AM

Been there done that.

Note that the fuel supply system operates below atmospheric pressure. If there is a hole in the system somewhere you will not leak fuel, you will draw in air. The hole may not open up unless the system is warm.

If the 6 clear lines between the fuel components under the hood are original, replace them on principle. This will take care of replacing the o-rings everyone talks about as well. Except for the one connection to the body of the IP that needs sealing washers. The part numbers for the 6 lines and the washers can be found on EPC or search around, I think whunter did a thread on this.

While you have it apart, remove the fuel control valve from the side of the IP and replace the o-ring behind there.

I also found that I wasn't getting a good seal between the top of the pre-filter (the one that looks like it could go in a mini coffee maker, not the one that looks like an oil filter) and the housing. There was some contamination there preventing a good seal.

You can get to everything except the one connection on the back of the IP if you just remove the washer bottle. For that last connection you will have to pull the manifold.

Also consider replacing the rubber hoses between the two steel lines coming from the tank, and the fuel heater (supply) and filter housing (return). For this you will need replacement clamps and Oetiker (Clic-R) pliers. This too will require pulling the manifold.

Also make note of the fasteners on the fuel lines, the white bail is pushed forward to release the connector. When you push the bail forward you are pressing on two latches under the cap. These latches pull back the barbs inside the connector that grab a ridge inside the port.

After plugging the end of the new hose into the port, slide the bail back about a 1/2 inch, this engages the barbs. The bail should wiggle back and forth slighly when it is in the correct position. Tug on the connector after it is mated, to be sure it is properly seated.

208benz · #6 07-30-2014, 09:31 AM

I replaced all the clear plastic fuel lines, delivery valve seals, and glow plugs 120,000 miles ago. Not a bad job with the right tools. It looks like it is time to do it again.

I have never done anything with the injectors. Would a clogged injector cause my problem? The engine runs fine after it is started.

Thanks for all the advice.

Mike

jay_bob · #7 07-30-2014, 11:05 AM

120 k might be the end of life on the fuel lines. Are they still clear and flexible or dark brown and stiff?

Have you changed out the o-ring on the back side of the fuel control valve? If not I would try that next. You can do that in a few minutes and the manifold does not have to come off.

Drain the washer bottle and remove it.
Using a T25 or T30 (sorry can't remember at the moment) loosen the 2 screws on the device and pull straight back to the left side of the car.
Don't disconnect any of the hoses or the electrical connector, there is enough slack to move it. The risk of introducing leaks in the hose connector o-rings is high if you separate the hoses. There is a nipple on the back of the device with an o-ring. This feeds the fuel into your IP.
Renew the o-ring, and swipe a little clean fuel on it for lube. Carefully push the valve back into the IP. Don't use the screws to draw it in, be sure it is seated flush to the IP body before tightening the screws. Otherwise you might crack the housing of the valve or strip out the aluminum body of the IP.

See if that helps, if not there are a few other things to try.

208benz · #8 07-30-2014, 09:30 PM

jay_bob, Thanks for the feedback. I will give it a try and let everyone know the results. Its gonna be a while, the car still runs and I'm super busy with the kids home from school.

Mike

TMAllison · #9 07-30-2014, 09:37 PM

My Inj's at 311k were OEM. Both old cars. Ran clean fuels, never veggie and usually replaced filters before they were due just cause they are cheap and its so easy to do. There is an oring on the bolt attaching the canister fuel filter. Some folks over tighten it and crush or rip it.

Suspect you have a leak that only appears when something expands from heating up.

Pre-filter would be the first thing I would check and then the oring behind the SOV if there aren't any obvious fuel line bubbles. Del valves would be last on my list, there is pressure there so if they leak fuel is emitted.

Olivier · #10 07-31-2014, 04:46 AM

As above I would change the Oring in the SOV.