Starting after changing the fuel filters - PeachParts Mercedes-Benz Forum

sokoloff · #1 05-08-2020, 07:22 PM

I haven't changed the fuel filters in the E300D for four of five years, so as part of the service I'm doing, I changed them both today. I know that since there is no manual primer that it might take a bit for the car to fire up, but I am not able to start it at the moment. I can't remember if I had this much problem when I changed them in the past, but I don't think so. When I tried to start the car the first time, it immediately started and ran for maybe five seconds and then shut itself off. Since then I crank and crank and get no start. This last time it sounded like it wanted to start, but never did. I've got about three quarters of a tank of fresh fuel, so there should be no problem getting the fuel to the engine. I even tried jacking up the rear end to try to help gravity move the fuel forward. Nothing helped. I've got the car on a battery charger right now. I didn't want to drain the battery down too much.

The pre filter was definitely dirty, but the primary filer had nice, clean diesel in it. I used the appropriate rubber rings, checked for leaks, but cannot find the issue.

Any ideas or do I just need to keep at it and it will eventually fire up?

Diesel911 · #2 05-08-2020, 08:12 PM

I don't know if there is room for it on your Engine but it is common to fill spin on filters with clean diesel fuel before you install them. That helps shorten the time the Fuel gets into the Fuel injection pump.

Assuming you already got air into the Fuel Injection Hard Lined loosen the line nuts at the Injectors and when you crank that will allow the air to escape fast and easily and tighten the nuts when you see fuel coming out of them regularly.

If you have another vehicle use your jumper cables to connect the 2 batteries and keep the other vehicle running while you crank.

Some people have suggested raising the rear of the vehicle so the fuel from the tank is going down hill to the Fuel Supply/Lift Pump but that was not for your specific vehicle.

Chris W. · #3 05-08-2020, 08:37 PM

Make sure your prefilter O ring is the right one and not damaged. I don't know about the filter for your 99, but for the 606 on my 95, the prefilter came without the O ring and I did not realize it. I changed both filters, pre and main,pre-filled the main, went to start, it ran for a sec and died. Could not restart. Long story short, I had no O ring on the prefilter. You said you had it, but check it again.

sokoloff · #4 05-08-2020, 08:51 PM

Thanks for the replies guys.

I've got new O-rings on both filters, although I did initially forget about the one in the pre filter.

I forgot about filling the filter with diesel to make it start faster. Wasn't there another fluid that could have been used too? Can't remember exactly, but I thought it was something other than diesel? A mind is a terrible thing to waste.

Car is charging overnight. I'll give it another shot in the AM.

Diesel911 · #5 05-08-2020, 09:28 PM

Quote:

Originally Posted by sokoloff

Thanks for the replies guys.

I've got new O-rings on both filters, although I did initially forget about the one in the pre filter.

I forgot about filling the filter with diesel to make it start faster. Wasn't there another fluid that could have been used too? Can't remember exactly, but I thought it was something other than diesel? A mind is a terrible thing to waste.

Car is charging overnight. I'll give it another shot in the AM.

Some people have said they fill the filter with ATF. That is not me recommending that.
Better I think would be 2 stroke Engine Oil because it is at least formulated to burn. I have read of people using it as a fuel additive but not straight into the Fuel Filter.

You can get a gallon of Diesel for the cost of one quart of ATF or 2 Stroke Oil.

sokoloff · #6 05-09-2020, 03:27 PM

Well, finally something went right. The car finally started. Not sure if either of these things helped, but the fuel filler cap was off and the right front of the car happened to be jacked up. If either of those things helped, my guess was the car being jacked up let gravity send the fuel to the left side or maybe it finally just primed itself.

Thanks for all your suggestions.

OM617YOTA · #7 05-09-2020, 07:08 PM

Glad you got her going again.

Just an FYI, prefilling fuel filters is no longer recommended best practice. Better to let the priming system fill the filter, so that all the fuel that gets to the clean side of the filter was filtered fuel. Even "clean" diesel is still much dirtier than fuel that's gone through your fuel filters.

sokoloff · #8 05-09-2020, 11:08 PM

Thanks, but the next time I change the fuel filters I probably will have forgotten my experience. I did think that maybe I should have dumped the diesel fuel that was in the old filter into the new one.

OM617YOTA · #9 05-10-2020, 01:13 AM

Most definitely do NOT dump the fuel out of the old filter into the new one! You'd be dumping the contaminants your old filter had filtered out into the clean side of the new filter, to be washed straight into your IP!

sokoloff · #10 05-10-2020, 08:49 AM

Duly noted - thanks.

Diesel911 · #11 05-10-2020, 01:00 PM

Quote:

Originally Posted by OM617YOTA

Glad you got her going again.

Just an FYI, prefilling fuel filters is no longer recommended best practice. Better to let the priming system fill the filter, so that all the fuel that gets to the clean side of the filter was filtered fuel. Even "clean" diesel is still much dirtier than fuel that's gone through your fuel filters.

His engine does not have a priming system. All it has is an air bleed within the Fuel Pressure Relief Valve. However, if a gulp of air from the Fuel Filter makes it into the Fuel Injection Pump housing and that Air gets into the Fuel Injection Hard Lines you are going to put a lot of stress on your Starter and Battery trying to get the air out of it.

That is helped/reduced somewhat if you loosen the Fuel Injection Hard Line Nuts at the injectors and give the Air an escape route.

Filling the Fuel Filter has been around before I started being a Diesel Mechanic back in 1975. So it is a well known practice. If it did any damage the practice would have been stopped long ago.

But like anything else people not doing their job a making sure clean diesel fuel with no other contaminants like dirt get into the Filter while they are filling it and installing it are to blame.

Some Companies like CAT tell you not to pre-fill there filters unless you use there special funnel that has a filter element in it. Cats also usually have a hand primer. You stick the funnel inside of the Filter properly and fill the filter.

Additionally there is a lot of engines out there with no sort of manual primer.

The issue cries for the use of common sense.

I was also briefly a Wheeled Vehicle Mechanic in the US Army Reserve. The diesel trucks had 2 Fuel Filters that were 2 quarts each.
That is one gallon of Air that has to be removed if someone is lazy and installs new filters dry. And soldiers are lazy and yes the vehicle won't start for some times a battery killing long time.

Just for a story in the above case what you should do is change one filter fill the filter with clean diesel then start and run the Engine. Then you go to the other Filter and again fill it with clean diesel and start and run the engine. It can be messy but that is the least troublesome way to do it.
The same way with the Mercedes. Change the pre-filter first and start and run the engine and then do the spin-on filter and fill it if you can do that. If you have one use the hand primer even if you filled the filter and if the filter was installed dry use the hand primer until you think it is filled and then use the hand primer some more because that is easier then having to bleed the air out of the Hard LInes.