Injection Pump Lubrication? - PeachParts Mercedes-Benz Forum

#1 08-09-2003, 07:20 PM

Hey guys, working on the diesel, and during the search for the primer hand pump, I saw a red cap on the IP labeled OEL ... german for oil. I popped it off and saw a bone dry resevoir. Is the IP lubricated by its own oil supply ... and if so, would running dry cause a serious failure leading to smoking problems?

Thanks, Cassidy

psfred · #2 08-09-2003, 08:06 PM

Yes and yes.

Fill it up with 10W30 oil. It has an overflow pip e on the engine side, so if you put in too much, it will just pour out on the ground.

I don't expect a worn-out IP to give you smoke though, usually it will either fail to give good speed control or it won't start.

Are you still smoking?

Peter

coachgeo · #3 08-09-2003, 11:13 PM

what kinda car Cazzzidy?

P.E.Haiges · #4 08-10-2003, 10:47 AM

Cazzzidy,

Happened to me. Dry IP sump wore out the bearing in rear end of the IP and it didn't pump as much oil to rear cylinders. Can't remember if it caused engine to smoke. I had to get the pump rebuilt.

Newer IP are lubricated by oil from engine pressurized oiling system so this can't happen any more to the newer DIesels. This new IP oiling system started with the 5 cylinder engines.

P E H

#5 08-11-2003, 03:41 AM

Wow, good info guys, thanks.

Yeah, my rear cylinders are the culprit. Number 4 isnt firing and everything checks out (timing, compression, valves, injectors, etc) except for the IP. I think that #4 cylinders IP injection mechanisms are malfunctioning.

I think it is really silly to use an independant oil supply for the IP considering it uses regural weight motor oil. I never knew it even had an oil supply untill I saw a red cap down there... mabye the previous owner didnt either??

Well, I am this close (pinches air) to ordering a rebuilt IP. I just need to perform a height squirt and volume of fuel test. Damnit... $600 pissed away on a $2000 car ... for one part! At least I take refuge in the thought that it has new paint and a rebuilt motor (head AND block.)

P.E.Haiges · #6 08-11-2003, 08:18 AM

Cazzzidy,

Instead of ordering a rebuilt injection pump, you might get an estimate of having yours repaired. It might only need to be fixed on one cylinder and that would cost much less than a rebuilt one.

There should be a Diesel injection shop in your area that can test your pump and repair it. Last one I had done was a Roosa Master/Standyne and cost about $340. They originally quoted $375 but there were some parts that were OK and its an honest shop.

One advantage of a pump with its own oil supply is that you have clean oil in it, not that black oil from the engine.

P E H

autozen · #7 08-11-2003, 11:56 AM

Nothing wrong with self oiling pumps in countries where people respect and service their cars unlike the U.S where most people drive them into the ground and then try to sell by advertising they need a little TLC. People out there believe there is an oil God. When there engine freezes up and they see no oil on the dipstick, they immediately dump in 5 quarts hoping this offering will appease the oil Gods. The oil gods are manevelant, and they never answer. Anyway, PEH has a good point about fresh oil which is changed at every "E" service. The proper method is to back out or remove the bolt at the left rer of the pump and put a TIN drain pan under it. The oil is thinned by diesel that has slipped into the bottom of the pump. The draining oil sound pitch on the metal pan will change as the diesel is all floated out and pure oil starts to flow. Stop putting in new oil, let the excess oil drain a minute, close off the drain. The drain is not on the bottom of the pump like an oil pan, but is set up like the fill hole on a differential or stick trans. Remember to have the car level.

Peter

#8 08-11-2003, 05:45 PM

Yes, it is really a shame americans take such poor care of their cars. This diesel I have been maintaining very well for the 3 months I had it ... I simply never knew it had an IP oil supply. My mechanic didnt check it when he did a PPI (Post Purchase Inspection :p )on it either.

I added some oil to the pump and did a squirt test on it.

I removed all the lines and turned over the motor many times. The diesel fuel would not squirt into the air like I was told it would do. Instead, fuel would simply pool up in the nipples where the line connects ... sometimes squirting out a little bit (mabye an inch). It hardly looked like 1400PSI to me. Is this normal?

Cassidy

JimSmith · #9 08-11-2003, 06:12 PM

Cazzzidy,

The 1400 psi or more is only developed if there is an injector, which is really like a relief valve in a typical fluid sytem, to contain the fuel until it reaches the pressure set point of the injector. If there is nothing to make the pump work against, then the fuel from a single stroke, which is really not much fuel (do a simple calculation assuming 4000 rpm and getting 30 mpg at 60 mph and you will see what I mean) is all that comes out. With no flow restriction to speak of the fuel will kind of fall out the opening. If the engine is cranked really fast you might get a little trajectory but otherwise it is not likely.

The injection pump is a variable displacement, positive displacement type of pump. It will not generate any more pressure than it needs to in order to push that fixed volume out of its cavity. It is the nozzle in the injector that makes the pump generate that pressure to move the fluid. I hope this helps, Jim

coachgeo · #10 08-11-2003, 07:42 PM

cazzidy.... is this about the IP on your 220D?

psfred · #11 08-11-2003, 09:45 PM

Cazzidy:

You only get pressure with the pressure valve installed and an injector connected, as noted above.

DO NOT "test" the nozzles by attaching them to the injection lines in the open air! The fuel is atomized at high enough pressure that a supersonic shock wave follows the fuel in the prechamber, and this is quite enough pressure to inject the entire charge right through your skin. You will also be making a nice explosive mixture -- use a tester to check the nozzles, you have a hand pump there to control the injection and no spark source!

Peter

coachgeo · #12 08-11-2003, 09:58 PM

Read that as

BOOOM

OOPPPS.