76 240D, fuel contamination problems
76 240D, fuel contamination problems
So, I have a 1976 240D, I believe it is the OM616 engine and has a four speed. I've owned it for abut two years now, and until recently it always ran like a top.
I let it sit for about three months, and couldn't get it started after. So I took it to an independent Mercedes mechanic. He found the fuel filter to be extremely clogged, in fact the worst he had ever seen. So he replaced it, and the car ran like a champ. But, after shut down, it would not restart.
He replaced the injectors, ran again, but would not restart. When troubleshooting, he found the fuel filter again clogged beyond belief. Our current hypothesis is that someone put something in the tank.
After cleaning the tank, filters, and fuel lines, he has no fuel pressure coming out of the injector pump, even when running off of a separate fuel cell.
Any suggestions for what is next? I am thinking, clean out the tank again, clean all fuel lines, replace all filters, and try a fuel purge and let it soak for a bit. Can't find a replacement injector pump, and cheapest rebuild service is over a grand.
Any advice would be greatly appreciated. Thank you!
First post!
So, I have a 1976 240D, I believe it is the OM616 engine and has a four speed. I've owned it for abut two years now, and until recently it always ran like a top.
I let it sit for about three months, and couldn't get it started after. So I took it to an independent Mercedes mechanic. He found the fuel filter to be extremely clogged, in fact the worst he had ever seen. So he replaced it, and the car ran like a champ. But, after shut down, it would not restart.
He replaced the injectors, ran again, but would not restart. When troubleshooting, he found the fuel filter again clogged beyond belief. Our current hypothesis is that someone put something in the tank.
After cleaning the tank, filters, and fuel lines, he has no fuel pressure coming out of the injector pump, even when running off of a separate fuel cell.
Any suggestions for what is next? I am thinking, clean out the tank again, clean all fuel lines, replace all filters, and try a fuel purge and let it soak for a bit. Can't find a replacement injector pump, and cheapest rebuild service is over a grand.
Any advice would be greatly appreciated. Thank you!
https://www.google.com/search?q=300d+tan...86&dpr=0.9
Sometimes we flip flop the supply/return lines to help clear it with out removing. Or you could remove it and have a look at it.
However, if the pump can't make pressure even off a jug then maybe that's not the problem. Maybe the seals inside the 'lift pump' are blown out.
https://www.google.com/search?q=mercedes...86&dpr=0.9
You can sit there pumping on that thing by hand and see if you can get any fuel to go through the spin on filter. Also can crank the starter to achieve the same goal.
Ought to be arrows on the fuel filter housing pointing the flow direction. If you open the connection after the filter and pump by hand or with the starter. Then, fuel ought to flow through a new clean filter sooner or later. If not, I would bet on a broken lift pump.
Also, prefill the filter with diesel from a jug before beginning this procedure.
That lift pump only cost like $150 brand new and takes about 20 min to swap on. I wouldn't worry about $1000 IP rebuild. Even someone here would sell you an IP far cheaper. But changing that out takes considerably more hassle.
Nice body, tons of ridiculous mechanical issues - 300d turbo 82' /motor 85'
There is also a screen in the bottom of the tank.
https://www.google.com/search?q=300d+tan...86&dpr=0.9
Sometimes we flip flop the supply/return lines to help clear it with out removing. Or you could remove it and have a look at it.
However, if the pump can't make pressure even off a jug then maybe that's not the problem. Maybe the seals inside the 'lift pump' are blown out.
https://www.google.com/search?q=mercedes...86&dpr=0.9
You can sit there pumping on that thing by hand and see if you can get any fuel to go through the spin on filter. Also can crank the starter to achieve the same goal.
Ought to be arrows on the fuel filter housing pointing the flow direction. If you open the connection after the filter and pump by hand or with the starter. Then, fuel ought to flow through a new clean filter sooner or later. If not, I would bet on a broken lift pump.
Also, prefill the filter with diesel from a jug before beginning this procedure.
That lift pump only cost like $150 brand new and takes about 20 min to swap on. I wouldn't worry about $1000 IP rebuild. Even someone here would sell you an IP far cheaper. But changing that out takes considerably more hassle.
Nice body, tons of ridiculous mechanical issues - 300d turbo 82' /motor 85'
(do a search for "dieselpest", I don´t know the english word, direct translation would be "diesel black death")
which is a bacteria infection of a small amount of water in your diesel tank.
Typically occurs when vehicles are sitting for a longer period of time through changing temperatures / water condensation in your diesel tank.
The bacteria lives in the water and eats your precious diesel. The product is the muddy stuff you describe.
If so, clean the injectors, injection pump, lift pump with a mixture of 50% fully synthetic engine oil and 50% Gasoline, fuel lines, tank, and so on with pure gasoline.
You will need a chemical fuel additive like "Grotamar" or "Liqui Moly boat biocide" to add to the diesel tank after cleaning, otherwise the bacteria will not die.
Gruß
Volker
I almost want to bet you got the "dieselpest"
(do a search for "dieselpest", I don´t know the english word, direct translation would be "diesel black death")
which is a bacteria infection of a small amount of water in your diesel tank.
Typically occurs when vehicles are sitting for a longer period of time through changing temperatures / water condensation in your diesel tank.
The bacteria lives in the water and eats your precious diesel. The product is the muddy stuff you describe.
If so, clean the injectors, injection pump, lift pump with a mixture of 50% fully synthetic engine oil and 50% Gasoline, fuel lines, tank, and so on with pure gasoline.
You will need a chemical fuel additive like "Grotamar" or "Liqui Moly boat biocide" to add to the diesel tank after cleaning, otherwise the bacteria will not die.
Gruß
Volker
priming the IP?
if not,before the IP recall/rebuilt you can try to take
lift pump and DV's from IP,hard lines and soak those in pure gasoline
for a day or two...new fuel filters,separate fuel cell and try again
p.s did he air purged hard lines while changing injectors?
good luck
ChO
.
500SEC euro gen II powered by OM617a stolen from 84 300SD .... with 280se transmission now
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after second fuel filter change did you hear hissing while
priming the IP?
if not,before the IP recall/rebuilt you can try to take
lift pump and DV's from IP,hard lines and soak those in pure gasoline
for a day or two...new fuel filters,separate fuel cell and try again
p.s did he air purged hard lines while changing injectors?
good luck
ChO
.
500SEC euro gen II powered by OM617a stolen from 84 300SD .... with 280se transmission now
----------------------------------------------------------
.
I'm going to try to attach a photo of the IP. My mechanic is not familiar with this particular IP, I was wondering if any of you guys had one like it or know any background? Just in case I have to replace it.
Thanks,
John
We are going to try cleaning everything as you guys have suggested, and also purge the IP and rebuild the injectors. Definitely going to run biocide through the fuel system as well. I'll keep you posted on the results.
I'm going to try to attach a photo of the IP. My mechanic is not familiar with this particular IP, I was wondering if any of you guys had one like it or know any background? Just in case I have to replace it.
Thanks,
John
that kind of IP uses separate oil ....via red plug
also vacuum of governor has to be checked IIRC...
you might wanna find a bit older mechanic
/
500SEC euro gen II powered by OM617a stolen from 84 300SD .... with 280se transmission now
----------------------------------------------------------
.
.
that kind of IP uses separate oil ....via red plug
also vacuum of governor has to be checked IIRC...
you might wanna find a bit older mechanic
/
500SEC euro gen II powered by OM617a stolen from 84 300SD .... with 280se transmission now
----------------------------------------------------------
.
Suctioning was made more effective by parking in such a way that one corner of the tank was much lower than the rest. That moved the water and remaining crud to the low point and facilitated sucking it out. Some 1/4" hose taped to some stiff wire made for a good suction wand.
Some of what was suctioned out:
The tank strainer:
As pointed out above, you have something living in your fuel tank. First kill it with biocide, then remove the tank sender and inspect. The bugs live on water and diesel. Since you probably want diesel in the tank, then you absolutely need to remove all the water. Otherwise your tank will just get re-infected from the next filler nozzle. I had to suction the tank numerous times before I got all the dead material out.
Suctioning was made more effective by parking in such a way that one corner of the tank was much lower than the rest. That moved the water and remaining crud to the low point and facilitated sucking it out. Some 1/4" hose taped to some stiff wire made for a good suction wand.
Some of what was suctioned out:
The tank strainer:
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