1970 Mercedes 280sel Fuel Problem - Page 2 - PeachParts Mercedes-Benz Forum

Arthur Dalton · #16 12-28-2006, 07:40 AM

There is no pump in the tank, only the main screen. Ther pump is housed in the cover you mentioned, but it sounds like someone has converted yours to an in-line pump.
What filters did you get??????

meltedpanda · #17 12-28-2006, 09:17 AM

sounds a little strange, my only advice is to make sure you disconnect battery and discharge any static electricity you may have before connecting and disconnecting lines and wires (where gas is involved)
We want you around to keep sharing

hoodun · #18 12-28-2006, 07:46 PM

so it looks like someone replaced the original fuel pump with a tiny aftermarket pump that i belive said 2.5-4psi. (i'll have to double check) is this the problem?

i bought an injector pump air filter and a regular big filter with the seal.

i put a wrench to the old cracked injector pump air filter and tourqed it only to break the entire housing.

it is the injector housing attached to the 6 fuel injectors housing. can you disconnect this piece from the section where the six lines are? it looks like two pieces. i may be garaging this car for a while until i can find a cheap injector unit.

below are the photos of the part i just destroyed. its the square looking part. you can see the 6 injector housing attached to it. in the close up photo, you can also see the missing filter (injector air filter) that is broken off. i was trying to remove and replace that part but...
anyone know where i can find this part? i live in san francisco so there has to be a 280sel in one of the junkyards. right?

hoodun · #19 12-29-2006, 02:23 AM

am i going crazy: http://www.aremco.com/a15.html

meltedpanda · #20 12-29-2006, 09:25 AM

If you mean that you might try this stuff - yup - you would be crazy
Fix it right or you will have many headaches down the road, literally

hoodun · #21 12-30-2006, 06:04 AM

has anyone ever done this or am i the only one. i cracked the aluminum right off while trying to attach the new air filter... i found the part but have not heard back about the price yet. i also found an original fuel pump. should i buy this? since the one i have is not the original type. is it possible that the small aftermarket inline pump could be causing my problems?

i agree that the glue wouldn't be a good idea. the whole thing must be a calling to pull apart and clean out the entire fuel system. any advice on this?

thanks

Arthur Dalton · #22 12-30-2006, 08:04 AM

Test the replacement pump they put in there [ although I suspect it does not have volume requirements of original] with a simple flow test.

The easiest way is to disconnect the fuel feedline at the engine filter canister. This has a ball/flare fitting that a clear hose will slip over. Put the other end of the test hose in a measure container and turn on the key. This will energize the pump and you are looking to fill 1 ltr of fuel into the container in 15 secs. It is best to have 1/2 tank of fuel when doing a flow test. After that test , you can also do a pressure test..looking for at least 13/14 psi..................
If these specs are cool, then that pump is sufficient and you then want to take the same test AFTER the filter canister. If that drops a large amount, you have a plugged canister filter. If these spec can not be obtained , then that pump is not cutting it. Going with the specs on the pump, it is probably a pump for carb engined system...not enough volume/pressure for a 108/MFI chassis.
None of these test should be done without looking at the tank screen on an old chassis..probably NEVER been checked. [ an easy tool for this hex plug is an inverted spark-plug socket.] The reason someone changed the pump in the first place may well be b/c they didn't check the tank screen !!!
Won't be the first one I've seen.......... The pump relies on gravity feed from the tank, so you can see where the screen has to be verified as clear.

I have the feeling you do not have a lot of wrench time , so you may want to gve this info to a mechanic to save yourself some problems , as you are working w/GAS !!!

hoodun · #23 12-30-2006, 05:16 PM

here is the exact fuel pump. can't believe it ran at all with this:

http://cgi.ebay.com/ebaymotors/2-5-4-psi-Electric-fuel-pump_W0QQitemZ230071663262QQihZ013QQcategoryZ33555QQcmdZViewItem
good news is that someone just quoted me $100 on an original used pump

i still have the fuel distribution problem since i cracked the housing to the fuel distributor. it looks like i can just replace the square part but it will find out once i pull it apart. i am being careful about not allowing too many fumes out. i clamped the hose from the fuel tank while pulling apart the distribution unit.
thanks again. yes i am a newbie. i work as a computer tech so i have the attention to detail...as long as i have your guys help.

meltedpanda · #24 12-30-2006, 05:31 PM

and you have disconnected battery and grounded vehicle

Arthur Dalton · #25 12-30-2006, 06:03 PM

Your photos are hard to make out , but if you referring to the can in the righthand photo, that is NOT the slide valve air filter..it is the barometric compensator...bad news , if that is the housing you have broken.

hoodun · #26 12-30-2006, 11:07 PM

yes that is the housing i broke. it snaped where the airfilter attaches. is the car now a parts car? i already started taking the part out and i am close to getting it off the car. i found a junkyard 280sel that i can get another unit from. is it best to take the whole fuel distribution unit or can i get away with just getting the square barometric box.
...or does anyone need any parts?

Gregg Bambo Jr. · #27 12-31-2006, 12:42 AM

here is a pic of the fuel pump used on an injected engine. Check out this thread for a pic an discussion on the tank fuel filter: Gas tank plug tool size?

Arthur Dalton · #28 12-31-2006, 06:26 AM

If you have broken the housing , you are best off with a new injection pump b/c the housing contains the linkage and govenor sections of the pump. These are calibrated to each pump and you will not be able to do that.
What is the pump # ? The last # after the R on the tag.

Arthur Dalton · #29 12-31-2006, 06:41 AM

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You keep telling me it is the air filter part you broke. But , the air filter does not mount to that housing..it mounts to the warmup thermo housing, which is easily changed
Tell me which part you are talking about. If it is the pump housing, then the barometric compensator is the part you torqued, not the air filter . So, WHICH is it ??????????????????????

http://www.sl113.org/forums/uploaded/ja17/20031023231515_injection%20left%20illus.%203.JPG

hoodun · #30 12-31-2006, 04:59 PM

i was trying to remove the air filter and the square box broke (barometric housing) the housing that the filter attaches to is fine. where that piece bolts in is cracked off. photos will be up soon.

and yes i put the battery in the trunk and discharged the positive terminal by connecting it to the ground. i am sure to ground myself when working on it. thanks for the needed concern.