Changed fuel filters, car won't start HELP!!!!

[rickjordan]

I just changed the fuel filters on my newly acquired W124 diesel. It's after I replaced the main filter and proceeded onto the inline, that I noticed that there was no manual hand pump tp prime the engine. I decided to crank her over anyways. The inline filter filled up and I did put some fuel in the main filter. The engine ran for only about 10 seconds and then stopped. I figured there was air in the line and that cranking her would push that through. At this point though I am afraid to kill my battery or kill the starter. Any help I can get would be appreciated. Fortunately this is our 3rd car, so I am not stranded, just frustrated.

[sixto]

I've heard that you should crank for as long as a minute though I've never done it that way.

I crack the outlet line at the main filter and crank until fuel seeps out (~ 5seconds). Then I crack all the injector lines and crank in 10 second bursts until fuel seeps out of each one, tightening those that show fuel. It hasn't taken more than 3 10 second cranks before there's fuel at every injector.

Sixto
91 300SE
87 300SDL
83 300SD

[Palangi]

I don't know much about the 6 cyl diesels, but seems like I have heard about an O ring associated with the main fuel filter. Not sure where it is. Maybe you have to transfer it from the old filter to the new one. Sorry I can't be more help.

[speedy300Dturbo]

Filling the filter fully with fuel fires up engine without failure!

[rickjordan]

Tomorrow I will remove the main filter and fill it completely, if it's not already. I didn't have any diesel on hand so I dumped what fuel there was from the old filter, into the new one. I know it didn't fill it completely, but I didn't have any other choice.

[lrg]

Speedy has it right. Fill the filter as full as you can and crank away. She'll eventually start. I've heard you can crank for a minute at a time without hurting the starter but I limit it to 30-40 seconds (allow it to cool a minute before trying again.) I try to change my 124 filter when the engine is still warm as it seems to catch easier and I don't need to glow so it leaves me extra juice for cranking.

[rickjordan]

I will definetly fill that filter up. You are right about the 1 minute of cranking. On most cars, the owner's manual says not to crank for more that 15 seconds. I was blown away by the fact that you can crank these startes for up to a minute without harm. Of course you have to have a fully charged battery.

[Rick Miley]

If you don't have any fuel on had, you can fill up the filter with diesel purge, 85+, diesel fuel catalyst, or similar product. They are mostly diesel fuel anyway.

[P.E.Haiges]

Rick,

Another reason not to change a filter before it is necessary. I say again, "If it ain't broke, don't fix it"

P E H

[Ken300D]

So far I've been sufficiently lucky to have changed the main fuel filters on both the 1987 and 1982 300Ds without any priming activity (either pump or loosen fuel lines) necessary. Really surprised me on the 1982 not to have to prime.

The tip for doing this on a warm car is a good idea.

A can of Diesel Purge is more than enough to fill the new filter. It is mostly diesel anyway. I'd use that or fresh diesel. For my part I'd rather just dump the fuel from the old filter. (You don't fill a new oil filter with the oil from the old, do you?) I get the new filter nearly in place (you might have to turn it sideways to do so) and then fill it.

I have a great respect for the PEH maintenance philosophy. But in the case of the main fuel filter I plan to replace it on the MB maintenance schedule whether clogged or not.

The 1982 just caught and ran. The 1987 caught and ran for five seconds, then missed and stopped. Another 5 seconds cranking and it ran from that point. Air bubble. If you did the pre-filter also, then you would have a larger air bubble to clear.

Ken300D

[rickjordan]

Well I got her started, and just about killed the battery doing it. I checked the fuel filter and it was full already. I crank it a few more time and nothing. I pulled the overflow line off the the number 1 injector and fuel came out. SO that told me that fuel was getting to #6 injector and working it's way back. I crank it again, a few times and she finally caught.
The reason I was changing the filter is because when ever I get a "new" car, I go through and change all fluids and filters, to establish a new baseline for future maintenance. Thanks again for all the tips.

The tip I got recently was to put the new filter in a jar of diesel and soak it full- this may be what is called "filling it" in previous posts- haven't done it yet so can't report on how well it works.

I put my fuel filters on dry, then crank it for 30-40 seconds and it starts right up. These are self-priming injection pumps.